JP2012065396A - Electrically-driven work machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrically-driven work machine equipped with an electric drive device capable of improving convenience at the time when charging a power storage element with electric power from an external power source such as a commercial power system, and simplifying a circuit configuration than before.SOLUTION: An electrically-driven work machine 100 is equipped with an electric drive device 10 containing a plurality of inverters 11,... for respectively driving a plurality of motors M,... with the same DC voltage supplied from a power storage element BT. The electrically-driven work machine 100 is equipped with first opening/closing means SWa which allows electrical conduction or shielding between a first leg group G1 and a connection leg group Gn. The electrically-driven work machine 100 further includes first connection terminals T1 and T2 for connecting a first inductor L1 between the middle point of leg LG1 of the first leg group G1 and the middle point of leg LG6 of the second leg group G2, as well as second connection terminals T3 and T4 for connecting an external power supply PW by way of a second inductor L2 between the middle point of leg LG7 of a third leg group G3 and the middle point of leg LG12 of a fourth leg group G4.

Description

  The present invention relates to an electric work machine including an electric drive device that charges a power storage element such as a storage battery with electric power from an external power source such as a commercial power system and drives a motor by the power storage element.

  As a conventional electric drive device that charges a power storage element such as a storage battery with power from an external power source such as a commercial power system and drives the motor with the power storage element, a configuration described in Patent Document 1 is disclosed.

  FIG. 24 shows a circuit diagram described in Patent Document 1 for charging a storage battery from a commercial power system.

  In the circuit configuration shown in FIG. 24, a rectifying module A2 is provided in parallel with an inverter A1 connected to a motor M1 connected to an AC 100V commercial power source. In the rectifying module A2, two sets (A21a, A21b), (A22a, A22b) in which two diodes are arranged in series are arranged in parallel, and these diodes (A21a, A21b), (A22a, A22b) are arranged in parallel. Thus, the capacitor A3 is provided. Between each of the diodes (A21a, A21b), (A22a, A22b) arranged in series, a ground side charger A4 connected to an AC200V commercial power supply is connected via a port A5 for inductive connection. A switch A6 is provided on one of the wires connecting A5 and the rectifying module A2. When charging with the 100V commercial power source, the storage battery A0 is charged with the switch A6 opened. On the other hand, when charging with the 200V commercial power source, the storage battery A0 is closed with the switch A6 closed. Is charged.

  In other words, the circuit configuration shown in FIG. 24 is configured as separate paths for the AC 100V commercial power system and the AC 200V commercial power system.

JP 2000-354331 A

  However, in such a conventional electric drive device, an AC 100V commercial power system that outputs a commercial power system voltage such as 100V or 120V and an AC 200V commercial power system that outputs a commercial power system voltage such as 200V, 230V, or 240V are used. Since they are separate paths, convenience in charging the storage element with power from an external power source is not good. Moreover, in order to induce a voltage in the inductance of the port A5 in the ground side charger A4, the current flowing through the inductance of the paddle A7 is converted into a high frequency switching frequency by the switching circuit A41. It is necessary to provide a transformer and a step-up DC-DC converter constituted by the switching circuit A41, and the circuit configuration becomes complicated accordingly.

  Therefore, the present invention includes an electric drive device that can improve the convenience when charging a power storage element with electric power from an external power source such as a commercial power system, and can simplify the circuit configuration as compared with the prior art. An object is to provide an electric working machine.

  The present invention relates to a bidirectional buck-boost DC-DC converter and a rectifier that replace an existing inverter (a motor driving inverter that is not used when charging a storage element) provided in an electric working machine when charging the storage element. It is completed based on the knowledge of the present inventor that it is diverted.

  That is, in order to solve the above-described problems, the present invention provides an electric work including an electric drive device having a plurality of inverters that are supplied with the same DC voltage from power storage elements such as a storage battery and a capacitor and respectively drive a plurality of motors. Wherein the electric drive unit is configured to divide each leg included in the plurality of inverters into four leg groups each having one or more legs. Electrically connecting between the first leg group in which the power storage element is connected to both ends and the connection leg group including the second leg group and the fourth leg group in which both ends are connected to each other. And a first opening / closing means for blocking, wherein a first inductor is connected between a midpoint of at least one leg of the first leg group and a midpoint of at least one leg of the second leg group. A commercial power system or the like via a second inductor between one connection terminal and a midpoint of at least one leg of the third leg group and a midpoint of at least one leg of the fourth leg group. Provided is an electric working machine having a second connection terminal connected to an external power source.

  In the present invention, when the power storage element is charged with electric power from the external power source, the first opening / closing means electrically disconnects (opens) the first leg group and the connection leg group. Thus, the plurality of existing inverters can be used as a bidirectional buck-boost DC-DC converter and a rectifier.

  That is, the first opening / closing means electrically cuts off between the first leg group and the connection leg group, and the middle point of at least one leg of the first leg group and the second leg group A bidirectional buck-boost type DC-DC converter may be configured by the first and second leg groups and the first inductor by connecting the first inductor between at least one leg midpoint. In addition, a rectifier can be configured by the third and fourth leg groups. And connecting between the midpoint of at least one leg of the third leg group and the midpoint of at least one leg of the fourth leg group via the second inductor, respectively. Thus, the power supplied from the external power source through the rectifier constituted by the third and fourth leg groups and the second inductor is constituted by the first and second leg groups and the first inductor. The electric storage element can be charged by controlling the bidirectional buck-boost type DC-DC converter.

  As described above, according to the present invention, in the electric drive device, the plurality of existing inverters are electrically disconnected between the first leg group and the connection leg group by the first opening / closing means. Can be used as a bidirectional buck-boost DC-DC converter and a rectifier, so that the external power supply path is the same without providing separate paths for the AC100V commercial power system and the AC200V commercial power system. It is possible to correspond to a plurality of commercial power system voltages on the route, and thereby it is possible to improve convenience when charging the power storage element from the external power source. In addition, it is not necessary to separately provide a circuit for the bidirectional step-up / step-down DC-DC converter and the rectifier. Furthermore, as in the configuration described in Patent Document 1, a transformer or a step-up DC-DC converter is used for high-frequency conversion. There is no need to provide it, and the circuit configuration can be simplified accordingly.

  In the present invention, the first inductor is operated between the middle point of at least one leg of the first leg group and the middle point of at least one leg of the second leg group. And the connection of the second inductor and the external power source between the midpoint of at least one leg of the third leg group and the midpoint of at least one leg of the fourth leg group. Although it may be performed artificially by a user's manual operation, it is preferable to perform it automatically. That is, the electric drive device electrically cuts off the connection between the first leg group and the connection leg group by the first opening / closing means when charging the power storage element with electric power from the external power source, The first inductor is connected between the midpoint of at least one leg of the first leg group and the midpoint of at least one leg of the second leg group, and at least of the third leg group. It is preferable to connect the midpoint of one leg and the midpoint of at least one leg of the fourth leg group to the external power supply via the second inductor.

  In this specific matter, when the power storage element is charged with power from the external power supply, the operation of the first opening / closing means, the connection of the first inductor, and the connection of the second inductor and the external power supply are automatically performed. It can be performed, and the operability by the user can be improved accordingly.

  In the present invention, the electric drive device can be exemplified by a mode in which the second inductor between the third leg group and the fourth leg group constitutes a part of the autotransformer.

  In this particular matter, the rated voltage of the inverter in the third and fourth leg groups is set to the voltage of the external power supply by using the autotransformer that shares a part of the winding between the primary side and the secondary side. Thus, even when the rated voltage of the inverter in the third and fourth leg groups does not correspond to the voltage of the external power supply, the power from the external power supply can be supplied.

  In the present invention, the electric drive device can be exemplified by an aspect in which the second inductor between the third leg group and the fourth leg group constitutes a part of a compound winding transformer.

  In this specific matter, the rated voltage of the inverter in the third and fourth leg groups corresponds to the voltage of the external power supply by using the multi-winding transformer that is physically insulated on the primary side and the secondary side. In addition, safety can be improved.

  In the present invention, in the electric drive device, the number of legs included in the first leg group and the number of legs included in the second leg group are two or more and the same number. A mode in which two or more first inductors are respectively connected between a midpoint of two or more legs and a midpoint of two or more legs in the second leg group can be exemplified.

  In this specific matter, since two or more first inductors are respectively connected between the midpoints of two or more legs in the first and second leg groups, the power capacity for charging the charging element is accordingly increased. Can be increased.

  In the present invention, in the electric drive device, the number of legs included in the first leg group and the number of legs included in the second leg group are 3, and the plurality of motors are included in the first leg group. Any one of the first motors is connected as the first inductor, and one of the remaining motors is connected to the second leg group as the first inductor, and the first leg group is connected. And a second opening / closing means for electrically conducting and blocking between the middle points of the field windings of the first motor connected to the first motor and the second motor connected to the second leg group. It can be illustrated.

  In this specific matter, when the power storage element is charged with electric power from the external power source, the second opening / closing means is connected to the first motor group and the second leg group connected to the first leg group. Further, by conducting between the middle points of the field windings with the second motor, the existing first and second motors can be used as the first inductor, and the cost can be reduced accordingly.

  In the present invention, the second opening / closing means may be artificially operated by a user's manual operation, but it is preferable to automatically operate the second opening / closing means. That is, when the electric drive device charges the power storage element with electric power from the external power source, the second opening / closing means uses the second opening / closing means between the middle points of the field windings of the first motor and the second motor. It is preferable to be configured to be electrically connected.

  In this specific matter, when the power storage element is charged with electric power from the external power source, the second opening / closing means can be automatically operated, and the operability for the user can be improved accordingly.

  In the present invention, in the electric drive device, the number of legs included in the third leg group and the number of legs included in the fourth leg group are two or more and the same number. A mode in which the other end sides of two or more second inductors each having one end connected to the external power source is connected to the midpoint of two or more legs in the leg group, respectively.

  In this specific matter, since the other end side of the second inductor is connected to the middle point of two or more legs in the third and fourth leg groups, the power capacity for charging the charging element is increased accordingly. Can be increased.

  In the present invention, in the electric drive device, the number of legs included in the third leg group and the number of legs included in the fourth leg group are 3, and the plurality of motors are included in the third leg group. Any one of the third motors is connected as the second inductor, and any one of the remaining four motors is connected to the fourth leg group as the second inductor, and the third leg group is connected. A mode in which a middle point between field windings of the third motor connected to the fourth motor and the fourth motor connected to the fourth leg group is connected to the external power source can be exemplified.

  In this specific matter, between the midpoints of the field windings of the third motor connected to the third leg group and the fourth motor connected to the fourth leg group is connected to the external power source. Therefore, the existing third and fourth motors can be used as the second inductor, and the cost can be reduced accordingly.

  In the present invention, at least one of the plurality of motors has a first field winding that is wound from the field winding for rotating the motor so as to constitute a part of the autotransformer. A first additional winding motor is used, and the electric drive device can be exemplified by a configuration in which the first additional winding motor is connected as the single-turn transformer.

  In this specific matter, even when the rated voltage of the inverter in the third and fourth leg groups does not correspond to the voltage of the external power supply, the power from the external power supply can be supplied, and the existing first One additional winding motor can be used as the autotransformer in which a part of the winding is shared between the primary side and the secondary side, and the cost can be reduced accordingly.

  In the present invention, at least one of the plurality of motors has a second field winding wound with the field winding for motor rotation so as to form a part of a multi-turn transformer. It can be a winding motor, and the electric drive device can be exemplified by a configuration in which the second additional winding motor is connected as the compound winding transformer.

  In this specific matter, even when the rated voltage of the inverter in the third and fourth leg groups does not correspond to the voltage of the external power supply, the power from the external power supply can be supplied, and the existing first Two additional winding motors can be used as the above-described double-winding transformer that is physically insulated between the primary side and the secondary side, so that the cost can be reduced and the safety can be improved. .

  By the way, when charging the power storage element with electric power from the external power source (particularly a single phase system), a bidirectional buck-boost type DC-DC converter constituted by the first and second leg groups and the first inductor is used. It is preferable that the current flowing to the external power supply side is a sine wave current in phase with the voltage waveform of the external power supply. However, the capacitance of the DC-side capacitor as viewed from the second, third, and fourth leg groups connected to the external power source is large (for example, greater than about 20 μF, or greater than about 30 μF, or even about 100 μF). If the DC side capacitor is used as a boundary, the external power supply side and the bidirectional buck-boost DC-DC converter side are electrically separated. Then, the current that flows to the external power source side of the bidirectional buck-boost DC-DC converter cannot be controlled by the bidirectional buck-boost DC-DC converter. For this reason, the current flowing to the external power supply side of the bidirectional buck-boost type DC-DC converter cannot be a current having a waveform in phase with the waveform of the current flowing to the external power supply.

  In this regard, in the present invention, the bidirectional buck-boost DC-DC converter constituted by the first and second leg groups and the first inductor is connected to the external power supply side of the bidirectional buck-boost DC-DC converter. The capacitance of the DC-side capacitor as viewed from the second, third, and fourth leg groups is small enough to control the flowing current (for example, 100 μF or less, more preferably 30 μF or less, more preferably 20 μF or less). In other words, the electric drive device has a capacitance of 100 μF of the DC-side capacitor as viewed from the second leg group, the third leg group, and the fourth leg group connected to the external power source. It is preferable that the configuration is as follows.

And the said electric drive device can be made into the following aspect (a) and aspect (b). That is,
In the aspect (a), the electric drive device operates as a rectifier that does not switch the third leg group and the fourth leg group connected to the external power source, and further controls the current flowing to the external power source side. The first leg group or the second leg group is provided.

  In the aspect (b), the electric drive device switches the third leg group and the fourth leg group connected to the external power source to operate as a synchronous rectifier, and further controls the current flowing to the external power source side. In the first leg group or the second leg group.

  In the aspects (a) and (b) having such a configuration, the bidirectional buck-boost type DC-DC converter is configured by the bidirectional buck-boost type DC-DC converter constituted by the first and second leg groups and the first inductor. -The current flowing to the external power supply side of the DC converter can be controlled, whereby the current flowing to the external power supply side of the bidirectional buck-boost type DC-DC converter is sine in phase with the voltage waveform of the external power supply. It can be a wave current.

  Moreover, in the aspect (a), since the third leg group and the fourth leg group connected to the external power supply are operated as a rectifier that does not switch, high-frequency switching of the third leg group and the fourth leg group is suspended. Since this can reduce switching loss, power conversion efficiency can be improved accordingly.

  In the aspect (b), although the third leg group and the fourth leg group connected to the external power source are switched, the third leg group and the fourth leg group are operated in particular as the synchronous rectifier is operated. Is a rectifier that does not switch the third leg group and the fourth leg group when the switching element is a reverse conducting semiconductor element (specifically, MOSFET or the like) that exhibits linear voltage-current characteristics when the switching element is turned on In other words, the power conversion efficiency can be improved as compared with the case of operating as a semiconductor element such as a diode that exhibits nonlinear voltage-current characteristics.

  In the present invention, the human-side operation of the DC-side capacitors as viewed from the second leg group, the third leg group, and the fourth leg group connected to the external power source is 100 μF or less. However, it is preferable to configure automatically. That is, when the electric drive device charges the power storage element with electric power from the external power source, the DC is viewed from the second leg group, the third leg group, and the fourth leg group connected to the external power source. It is preferable that the capacitance of the side capacitor is 100 μF or less.

  In this specific matter, when the power storage element is charged with power from the external power supply, the capacitance of the DC-side capacitor automatically viewed from the second leg group, the third leg group, and the fourth leg group. Can be made 100 μF or less, and the operability by the user can be improved accordingly.

  In the present invention, the electric drive device accumulates pulsating power that may be generated when charging the power storage element in the first inductor connected between the first leg group and the second leg group. The aspect made into the structure can be illustrated.

  In this specific matter, both the storage element and the DC-side capacitor with respect to the first inductor by a bidirectional buck-boost DC-DC converter constituted by the first and second leg groups and the first inductor. An operation mode that is not electrically connected to the first inductance (that is, an operation mode in which an internal short circuit is caused with respect to the first inductance) can be realized, and therefore, the bidirectional buck-boost DC-DC converter is connected to the external power supply side. In addition to controlling the flowing current, the current supplied to the power storage element can be made constant, whereby the frequency corresponding to the frequency of the external power supply to the power storage element (for example, the frequency of a single-phase system). Corresponding low frequency) pulsating current does not flow, and a constant current can easily flow, so that the power storage element can be charged efficiently. Can, moreover it is possible to prevent the temperature rise of power storage elements, which makes it possible to prevent the reduction of the service life of the power storage element.

  In the present invention, the electric drive device is configured such that a solar cell is connected to an excess leg among the legs included in the plurality of inverters, and the power storage element can be charged with electric power from the solar cell. Can be illustrated.

  In this specific matter, the surplus leg to which the solar cell is connected can be used for charging the power storage element with the power from the solar cell, thereby effectively utilizing the surplus leg. be able to.

  In the present invention, the electric drive device may be configured to switch a plurality of legs in the first and second leg groups so that the phases of the plurality of phases of power are shifted. In addition, when the design allows a relatively small power capacity (for example, about one third of the rated power of the inverter), the electric drive device includes a plurality of electric power units in the first and second leg groups. Only one of the legs may be switched.

  In this specific matter, it is possible to reduce the high-frequency ripple flowing into the electrolytic capacitor provided on the power storage element side, thereby extending the life of the electrolytic capacitor, and the physical properties of the filter provided on the power storage element side. The size (size) can be reduced. In addition, when only one of the plurality of legs in the first and second leg groups is switched, the switching loss can be reduced as compared with the case of switching each leg, so that the power conversion efficiency is improved accordingly. be able to.

  In the present invention, the electric drive device may be configured to switch a plurality of legs in the third and fourth leg groups so that the phases of the plurality of phases of power are shifted. In addition, when the design allows a relatively small power capacity (for example, about one third of the rated power of the inverter), the electric drive device includes a plurality of the third and fourth leg groups. Only one of the legs may be switched.

  According to this specific matter, it is possible to reduce the high-frequency ripple flowing into the electrolytic capacitor provided on the external power supply side, thereby extending the life of the electrolytic capacitor, and to physically connect the filter provided on the external power supply side. The size (size) can be reduced. In addition, when only one of the plurality of legs in the third and fourth leg groups is switched, the switching loss can be reduced as compared with the case where each leg is switched, so that the power conversion efficiency is improved accordingly. be able to.

  As described above, according to the present invention, in the electric drive device, the first opening / closing means electrically cuts off (opens) the first leg group and the connection leg group, so that the existing The plurality of inverters can be used as a bidirectional buck-boost type DC-DC converter and a rectifier. Therefore, separate paths are provided for the AC 100 V system commercial power system and the AC 200 V system commercial power system as the external power source path. Without any problem, it is possible to correspond to a plurality of single-phase commercial power system voltages through the same path, and thus it is possible to improve convenience when charging the power storage element from the external power source. In addition, it is not necessary to separately provide a circuit for the bidirectional step-up / step-down DC-DC converter and the rectifier. Furthermore, as in the configuration described in Patent Document 1, a transformer or a step-up DC-DC converter is used for high-frequency conversion. There is no need to provide it, and the circuit configuration can be simplified accordingly.

1 is a circuit diagram showing a schematic configuration of an electric working machine according to an embodiment of the present invention in a single line diagram. It is a circuit diagram which shows schematic structure in the power running mode of 1st Embodiment in the electric working machine shown in FIG. It is a circuit diagram which shows schematic structure in the regeneration (charging) mode of 1st Embodiment in the electric working machine shown in FIG. It is a schematic block diagram which shows each switching element provided in each leg with one figure. It is a circuit diagram which shows schematic structure in the regeneration (charging) mode of 2nd Embodiment in the electrically-driven working machine shown in FIG. It is a circuit diagram which shows schematic structure in the regeneration (charge) mode of 3rd Embodiment in the electrically-driven working machine shown in FIG. It is a circuit diagram which shows schematic structure in the regeneration (charge) mode of 4th Embodiment in the electrically-driven working machine shown in FIG. It is a circuit diagram which shows schematic structure in the regeneration (charge) mode of 5th Embodiment in the electrically-driven working machine shown in FIG. It is a circuit diagram which shows schematic structure in the regeneration (charge) mode of 6th Embodiment in the electrically-driven working machine shown in FIG. 1 with a double-line diagram. It is a circuit diagram which shows schematic structure in the regeneration (charge) mode of 7th Embodiment in the electrically-driven working machine shown in FIG. It is a circuit diagram which shows roughly the winding state of the 3rd and 4th motor provided in the electric drive device of 8th Embodiment in the electric working machine shown in FIG. It is a circuit diagram which shows roughly the winding state of the 3rd and 4th motor provided in the electric drive device of 9th Embodiment in the electric working machine shown in FIG. It is a circuit diagram which shows schematic structure in the regeneration (charge) mode of 10th Embodiment in the electrically-driven working machine shown in FIG. 1 with a double track diagram. In the electric drive device according to the present embodiment, when the storage battery is charged with power from the grid, the schematic configuration of the bidirectional buck-boost DC-DC converter configured by the first and second leg groups and the first inductor FIG. It is explanatory drawing for demonstrating the operation example made to operate | move by the power running mode in the DC-DC converter shown in FIG. FIG. 15 is an explanatory diagram for describing an operation example in which the DC-DC converter illustrated in FIG. 14 is operated in a regeneration (charging) mode. FIG. 15 is a graph showing an example of specific operation waveforms when the DC-DC converter shown in FIG. 14 is operated in a regeneration (charging) mode. It is a graph for demonstrating an example of pulsation reduction operation | movement. It is a graph for demonstrating the other example of pulsation reduction operation | movement. It is explanatory drawing for demonstrating the advantage at the time of operating the switching element of a 3rd leg group and a 4th leg group as a synchronous rectifier, Comprising: (a) is a schematic diagram showing a switching element in an OFF state, (B) is a graph showing the current-voltage characteristics of the switching element in the off state, (c) is a schematic diagram showing the switching element in the on state, and (d) is a switching in the on state. It is a graph which shows the current-voltage characteristic (solid line) of an element compared with the current-voltage characteristic (broken line) of an OFF state. It is a circuit diagram which shows the state by which the solar cell is connected to the surplus leg in the electric drive device of 1st Embodiment. Only the three switching elements of the lower arm in a certain leg group in the case where it is configured to realize switching control of three-phase power as in the circuit configurations shown in the fourth and fifth embodiments and the sixth and seventh embodiments. It is a graph when it switches at the same timing, (a) is a graph which shows the time change of the switching timing of a switching element, (b) is the time change of the electric current which flows into a 1st and 2nd inductor. (C) is a graph which shows the time change of the electric current which flows into a switching element when switching a switching element, (d) is the electric current supplied to a storage battery when switching a switching element 5 is a graph showing a temporal change in current flowing through the DC-side capacitor on the system side. Only the three switching elements of the lower arm in a certain leg group in the case where it is configured to realize switching control of three-phase power as in the circuit configurations shown in the fourth and fifth embodiments and the sixth and seventh embodiments. FIG. 6 is a graph when switching is performed at different timings, where (a) is a graph showing a temporal change in switching timing of the switching element, and (b) is a temporal change in current flowing through the first and second inductors. It is a graph which shows a change, (c) is a graph which shows the time change of the electric current which flows into a switching element when switching a switching element, (d) is supplied to the storage battery when switching a switching element. It is a graph which shows the time change of the electric current and the electric current which flows into the DC side capacitor of a system side. It is a circuit diagram given in patent documents 1 which charge a storage battery from a commercial power system.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The following embodiments are examples embodying the present invention, and are not of a nature that limits the technical scope of the present invention.

  FIG. 1 is a circuit diagram showing a schematic configuration of an electric working machine 100 according to an embodiment of the present invention in a single line diagram. FIG. 2 is a circuit diagram showing a schematic configuration of the electric working machine 100 shown in FIG. 1 in the power running mode of the first embodiment in a double-line diagram. FIG. 3 is a circuit diagram showing a schematic configuration of the electric working machine 100 shown in FIG. 1 in the regeneration (charging) mode of the first embodiment in a double-line diagram. In FIG. 3, the control device 20 and the like are not shown. The same applies to FIGS. 5 to 10, 13 and 21 described later.

  FIG. 4 is a schematic configuration diagram showing the switching elements sw1 to sw24 provided in the legs LG1 to LG12 in one view. In FIG. 4, the switching elements sw <b> 1 to sw <b> 24 are all of the same type, and are therefore shown as one figure.

  An electric work machine 100 shown in FIG. 1 includes an electric drive device 10 to which electric power is supplied from a storage battery BT (an example of an electric storage element), and a plurality (four in this case) of motors M driven by the electric drive device 10. The storage battery BT is charged with power from a single-phase commercial power system (an example of an external power source, hereinafter simply referred to as a system) PW. In addition, when there are a plurality of storage batteries BT, the plurality of storage batteries BT can be connected in series and / or in parallel. Further, the storage battery BT may be a capacitor.

  The electric drive device 10 includes a plurality (four in this case) of motor drive inverters 11 that respectively drive a plurality of motors M,..., And a plurality (here, four) capacitors C,. Cc, Cd). As the motor M, a DC brushless motor or an induction (induction) motor can be used.

  Each of the motor drive inverters 11 includes a plurality of (here, 12) legs LG1 to LG12. An example of a leg is one in which two reverse conducting semiconductor elements are connected in series. As a reverse conduction type semiconductor element, a semiconductor element in which diodes are connected in parallel with the direction in which a current can flow can be reversed with respect to a semiconductor switch such as an IGBT (Insulated Gate Bipolar Transistor) or a GTO (Gate Turn-Off thyristor). Examples of semiconductor elements such as MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) in which parasitic diodes (or body diodes) exist in the structure of the semiconductor include, for example, reverse conducting IGBT elements, reverse conducting Type MOSFET element and reverse conduction type GTO element.

  In the present embodiment, each of the plurality of legs LG1 to LG12 includes two switching elements (sw1, sw2), (sw3, sw4), (sw5, sw6), (sw7, sw8), (sw9, sw10), (Sw11, sw12), (sw13, sw14), (sw15, sw16), (sw17, sw18), (sw19, sw20), (sw21, sw22), (sw23, sw24) are connected in series. In this case, the switching elements sw1 to sw24 are semiconductor elements (see FIG. 4) in which diodes D are connected in parallel with the direction in which a current can be passed to the semiconductor switch S such as IGBT or GTO reversed. Or a MOSFET reverse conducting semiconductor element.

  Here, the plurality of capacitors C,... (Ca, Cb, Cc, Cd) are electrolytic capacitors of several hundreds μF (for example, 400 μF to 800 μF) or more, and are respectively connected to the plurality of legs LG1 to LG12. One is connected in parallel for each of a plurality (three in this case) of legs.

  The electric drive device 10 includes a first opening / closing relay SWa that functions as first opening / closing means.

  The first open / close relay SWa includes one or more (here, three) legs (LG1 to LG3) and (LG4 to LG6) of the individual legs LG1 to LG12 included in the plurality of motor drive inverters 11,. , (LG7 to LG9), (LG10 to LG12), the first leg group G1 in which the storage battery BT is connected to both ends among the first to fourth leg groups G1 to G4 divided into four leg groups. In addition, the second leg group G2 to the fourth leg group G4 each having both ends connected to each other are electrically connected to and disconnected from the connection leg group Gn. The first open / close relay SWa is a relay switch that turns on / off current between the first leg group G1 and the connection leg group Gn. Specifically, the legs LG1 to LG3 of the first leg group G1 and the legs LG4 to LG12 of the connection leg group Gn are connected in parallel to each other, and the upper arm of the leg LG1 of the first leg group G1 (switching element sw1 ) Side and the positive electrode side of the storage battery BT are connected, and the lower arm (switching element sw2) side of the leg LG1 and the negative electrode side of the storage battery BT are connected.

  The first open / close relay SWa is provided on either the positive electrode side or the negative electrode side between the leg LG3 of the first leg group G1 and the leg LG4 of the second leg group G2. Here, in the first open / close relay SWa, the connection terminal Ta1 is connected to the upper arm (switching element sw5) side of the leg LG3 of the first leg group G1, and the connection terminal Ta2 is connected to the leg LG4 of the second leg group G2. It is connected to the upper arm (switching element sw7) side. The lower arm (switching element sw6) side of the leg LG3 of the first leg group G1 and the lower arm (switching element sw8) side of the leg LG4 of the second leg group G2 are connected to each other.

  Here, the upper arm refers to the arm from which current flows into the first to fourth leg groups G1 to G4, and the lower arm refers to the arm from which current flows from the first to fourth leg groups G1 to G4. Say.

  In addition, the electric drive device 10 includes at least one of the first inductor L1, the second inductor L2, the midpoint of at least one leg (here, the leg LG1) of the first leg group G1, and the second leg group G. First connection terminals T1, T2 for connecting the first inductor L1 between the middle points of the two legs (the same number as the legs of the first leg group G1) (here, the leg LG6), and the third leg group G3 Between the midpoint of at least one leg (here leg LG7) and the midpoint of at least one leg (the same number of legs of the third leg group G3) of the fourth leg group G4 (here leg LG12) It has 2nd connection terminal T3, T4 connected to the system | strain PW via the 2nd inductor L2.

[First Embodiment]
The electric drive device 10 (10a) of the first embodiment includes first to fourth switching relays SW1 to SW4 that function as switching means.

  The first switching relay SW1 is connected to one end of the first inductor L1 with respect to the first connection terminal T1 (common terminal) connected to the midpoint of at least one leg (here, the leg LG1) in the first leg group G1. It is a change-over switch that switches between the first connection terminal T2 connected to the side and the connection terminal Tm connected to any phase of the motor M connected to the first leg group G1. The midpoints of the remaining legs of the first leg group G1 (here, the legs LG2 and LG3) and the remaining phases of the motor M connected to the first leg group G1 are connected to each other.

  The second switching relay SW2 is connected to the first inductor L1 in addition to the first connection terminal T1 (common terminal) connected to the midpoint of at least one leg (here, the leg LG6) in the second leg group G2. It is a changeover switch that switches between the first connection terminal T2 connected to the end side and the connection terminal Tm connected to any phase of the motor M connected to the second leg group G2. The midpoints of the remaining legs of the second leg group G1 (here, legs LG4 and LG5) and the remaining phases of the motor M connected to the second leg group G2 are connected to each other.

  The third switching relay SW3 has one end of the second inductor L2 with respect to the second connection terminal T3 (common terminal) connected to the midpoint of at least one leg (here, the leg LG7) in the third leg group G3. It is a change-over switch that switches between the second connection terminal T4 connected to the side and the connection terminal Tm connected to any phase of the motor M connected to the third leg group G3. The midpoints of the remaining legs of the third leg group G3 (here, legs LG8 and LG9) and the remaining phases of the motor M connected to the third leg group G3 are connected to each other, and the second inductor The other end side of L2 and one side of the system PW are connected in series via a connection terminal Ta.

  The fourth switching relay SW4 is on the other side of the system PW with respect to the second connection terminal T3 (common terminal) connected to the midpoint of at least one leg (here, the leg LG12) in the fourth leg group G4. It is a changeover switch that switches between the connected second connection terminal T4 and the connection terminal Tm connected to any phase of the motor M connected to the fourth leg group G4. The midpoints of the remaining legs of the fourth leg group G4 (here, the legs LG10 and LG11) and the remaining phases of the motor M connected to the fourth leg group G4 are connected to each other.

  In the electric working machine 100 described above, in the electric drive device 10 (10a), when the storage battery BT is charged with the electric power from the system PW, the first leg group G1 and the connection leg group Gn are connected by the first opening / closing relay SWa. Between the first and second leg groups G1, G2 by switching the first and second switching relays SW1, SW2 to the first inductor L1 side. A bidirectional buck-boost DC-DC converter can be configured by LG6 and the first inductor L1. Thereby, the some existing inverter 11, ... can be diverted as a bidirectional buck-boost type DC-DC converter. Further, by switching the third and fourth switching relays SW3 and SW4 to the system PW side, a diode bridge rectifier can be configured by the legs LG7 and LG12 of the third and fourth leg groups G3 and G4. Thereby, the some existing inverter 11, ... can be diverted as a rectifier.

  The first and second powers are supplied from the system PW connected to the connection terminals Ta and Tb via the rectifier constituted by the third and fourth leg groups G3 and G4 and the second inductor L2. The storage battery BT can be charged by controlling the bidirectional buck-boost DC-DC converter constituted by the leg groups G1, G2 and the first inductor L1.

  When each motor M,... Is driven by electric power from the rechargeable battery BT, the first opening / closing relay SWa electrically conducts (closes) the first leg group G1 and the connection leg group Gn, Further, the first to fourth switching relays SW1 to SW4 are switched to the motors M,... And connected to the legs G1, G6 to connect the motors M,. Can be used as

  As described above, according to the electric working machine 100, in the electric drive device 10 (10a), the existing plurality of inverters 11,... Since the step-up operation, the step-down operation and the step-up / step-down operation can be performed by the pressure type DC-DC converter, the AC 100 V system commercial power system and the AC 200 V system commercial power system are not provided with separate paths as the system PW path. It is possible to correspond to a plurality of single-phase commercial power system voltages on the same path, and thereby it is possible to improve convenience when charging the storage battery BT from the system PW. In addition, it is not necessary to separately provide a circuit for the bidirectional step-up / step-down DC-DC converter and the rectifier. Furthermore, as in the configuration described in Patent Document 1, a transformer or a step-up DC-DC converter is used for high-frequency conversion. There is no need to provide it, and the circuit configuration can be simplified accordingly.

  The electric drive device 10 (10a) shown in FIGS. 2 and 3 automatically operates the first opening / closing relay SWa and the first to fourth switching relays SW1 to SW4.

  As shown in FIG. 2, the electric drive device 10 (10 a) further includes a control device 20. The control device 20 includes a processing unit 21 such as a CPU (Central Processing Unit) and a storage unit 22. The storage unit 22 includes a storage memory such as a ROM (Read Only Memory) or a RAM (Random Access Memory), and stores various control programs, necessary functions and tables, and various data.

  When the control device 20 detects a non-charged state in which the storage battery BT is not charged with the electric power from the system PW, the control device 20 turns on the first open / close relay SWa and turns the first to fourth switching relays SW1 to SW4 on the motors M,. It is set as the structure switched to the side. On the other hand, when the control device 20 detects a charging state in which the storage battery BT is charged with the electric power from the system PW, the control device 20 turns off the first open / close relay SWa and sets the first and second switching relays SW1 and SW2 to the first inductor. It is set as the structure which switches to the L1 side and switches 3rd and 4th switching relay SW3, SW4 to the system | strain PW side.

  Specifically, the control device 20 includes connection detection means for detecting that the system PW is connected. This connection detection means may be detected by a sensor that detects that the system PW is connected, or may be detected by a sensor that detects the voltage of the system PW. Thereby, the control apparatus 20 can recognize a non-charging state or a charging state.

  In the electric drive device 10 (10a) having such a configuration, the first opening / closing relay SWa and the first to fourth switching relays SW1 to SW4 are automatically operated when the storage battery BT is charged with electric power from the system PW. It is possible to improve the operability by the user.

  The first open / close relay SWa and the first to fourth switching relays SW1 to SW4 are operated by automatic operation by the connection detection unit, but are used instead of or in addition to the automatic operation by the connection detection unit. A non-charged state and a charged state may be artificially switched by a human operation.

[Second Embodiment]
By the way, when the rated voltage of the inverter 11 in the third and fourth leg groups G3 and G4 does not correspond to the voltage of the system PW, the power from the system PW cannot be supplied.

  From this point of view, in the electric drive device 10 (10b) of the second embodiment, the second inductor L2 between the third leg group G3 and the fourth leg group G4 divides a part of the winding from the primary side to the secondary side. And a part of the auto-transformer TR1 (see FIG. 5 described later) shared with each other.

  FIG. 5 is a circuit diagram showing a schematic configuration in a regeneration (charging) mode of the second embodiment in the electric working machine 100 shown in FIG. In addition, in the electric drive device 10 (10b) of the second embodiment shown in FIG. 5, the same elements as those of the electric drive device 10 (10a) of the first embodiment shown in FIGS. Description is omitted. Further, in the power running mode, in the case of the regeneration (charge) mode, the operation states of the changeover switches SW1 to SW4 are merely reversed. Therefore, in FIG. 5, the operations of the changeover switches SW1 to SW4 in the power running mode are performed. The state is not shown. The same applies to FIGS. 6 to 10, 13 and 21 described later.

  The electric drive device 10 (10b) of the second embodiment is an example when the rated voltage of the inverter 11 in the third and fourth leg groups G3 and G4 is smaller than the voltage of the system PW, as shown in FIG. In the autotransformer TR1, the side with the larger number of turns is connected to the system PW, and the side with the smaller number of turns is connected to the midpoint of the leg LG7 of the third leg group G3 and the midpoint of the leg LG12 of the fourth leg group G4. It is like that.

  By doing so, the rated voltage of the inverter 11 in the third and fourth leg groups G3 and G4 can be made to correspond to the voltage of the system PW, whereby the inverter 11 in the third and fourth leg groups G3 and G4 Even when the rated voltage is smaller than the voltage of the system PW, the power from the system PW can be supplied.

  When the rated voltage of the inverter 11 in the third and fourth leg groups G3 and G4 is higher than the voltage of the system PW, the side with the larger number of turns is set to the leg LG7 of the third leg group G3 in the autotransformer TR1. And the middle point of the leg LG12 of the fourth leg group G4, and the side with the smaller number of turns may be connected to the system PW.

[Third Embodiment]
FIG. 6 is a circuit diagram showing a schematic configuration in a regeneration (charging) mode of the third embodiment in the electric working machine 100 shown in FIG.

  From the viewpoint that the electrical drive device 10 (10c) of the third embodiment is preferably physically insulated on the primary side and the secondary side of the transformer for safety reasons such as leakage, FIG. As shown, the second inductor L2 between the third leg group G3 and the fourth leg group G4 constitutes a part of the multi-turn transformer TR2, and the multi-turn transformer TR2 It is connected to the system PW, and the side with the smaller number of turns is connected to the midpoint of the leg LG7 of the third leg group G3 and the midpoint of the leg LG12 of the fourth leg group G4.

  Thus, the rated voltage of the inverter 11 in the third and fourth leg groups G3 and G4 is changed to the voltage of the system PW by using the compound winding transformer TR2 that is physically insulated between the primary side and the secondary side. In addition, the safety can be improved.

  Also in the third embodiment, similarly to the second embodiment, when the rated voltage of the inverter 11 in the third and fourth leg groups G3 and G4 is larger than the voltage of the system PW, the compound transformer TR2 In this case, the side with the larger number of turns is connected to the midpoint of the leg LG7 of the third leg group G3 and the midpoint of the leg LG12 of the fourth leg group G4, and the side with the smaller number of turns is connected to the system PW. Good.

[Fourth Embodiment]
FIG. 7 is a circuit diagram showing a schematic configuration in a regeneration (charging) mode of the fourth embodiment in the electric working machine 100 shown in FIG. The configuration of the fourth embodiment on the system PW side is the same as the configuration of the third embodiment shown in FIG.

  As shown in FIG. 7, in the electric drive device 10 (10d) of the fourth embodiment, the number of legs included in the first leg group G1 and the number of legs included in the second leg group G2 are two or more ( 3 here) and the same number, and the midpoint of two or more (here three) legs LG1 to LG3 in the first leg group G1 and two or more (here three) in the second leg group G2. Two or more (three in this case) first inductors L1 (L1a, L1b, L1c) are connected to the midpoints of the legs LG4 to LG6, respectively.

  Specifically, the electric drive device 10 (10d) of the fourth embodiment is different from the electric drive device 10 (10c) of the third embodiment shown in FIG. 6 in that the first inductor L1 is replaced with three first inductors L1 ( L1a, L1b, L1c), and fifth to eighth switching relays SW5 to SW8 are added.

  Specifically, the first, fifth and sixth switching relays SW1, SW5, SW6 are respectively connected to the first connection terminals T1, T1, T1 connected to the midpoints of the legs LG1, LG2, LG3 of the first leg group G1. The first connection terminals T2, T2, T2 connected to one end of the first inductor L1 (L1a, L1b, L1c) with respect to T1 (common terminal), and the motor M connected to the first leg group G1 It is a changeover switch that switches connection terminals Tm, Tm, Tm connected to each phase.

  The second, seventh and eighth switching relays SW2, SW7, SW8 are respectively connected to the first connection terminals T1, T1, T1 connected to the midpoints of the legs LG5, LG4, LG3 of the second leg group G2. (Common terminal), the first connection terminals T2, T2, T2 connected to the other end of the first inductor L1 (L1a, L1b, L1c) and the motor M connected to the second leg group G2 It is a changeover switch that switches connection terminals Tm, Tm, Tm connected to each phase.

  In the electric drive device 10 (10d) of the fourth embodiment, the first inductor is arranged between the midpoints of the legs (LG1, LG2, LG3), (LG6, LG5, LG4) in the first and second leg groups G1, G2. Since L1 (L1a, L1b, L1c) is connected, the power capacity for charging the rechargeable battery BT can be increased accordingly.

  The electric drive device 10 (10d) of the fourth embodiment automatically operates the first opening / closing relay SWa and the first to eighth switching relays SW1 to SW8.

  Specifically, the control device 20 is configured to turn on the first open / close relay SWa and switch the first to eighth switching relays SW1 to SW8 to the motors M,... ing. On the other hand, when detecting the state of charge, the control device 20 turns off the first open / close relay SWa, and switches the first, second, and fifth to eighth switching relays SW1, SW2, SW5 to SW8 to the first inductor L1. It is set as the structure which switches to the (L1a, L1b, L1c) side, and switches 3rd and 4th switching relay SW3, SW4 to the system | strain PW side.

  In the electric drive device 10 (10d) having such a configuration, the first open / close relay SWa and the first to eighth switching relays SW1 to SW8 are automatically operated when the storage battery BT is charged with the electric power from the system PW. It is possible to improve the operability by the user.

  The first open / close relay SWa and the first to eighth switching relays SW1 to SW8 are operated by an automatic operation by the connection detection unit, but are used instead of or in addition to the automatic operation by the connection detection unit. A non-charged state and a charged state may be artificially switched by a human operation.

[Fifth Embodiment]
FIG. 8 is a circuit diagram showing a schematic configuration in a regeneration (charging) mode of the fifth embodiment in the electric working machine 100 shown in FIG. The configuration on the system PW side of the fifth embodiment is the same as the configuration of the third embodiment shown in FIG.

  As shown in FIG. 8, in the electric drive device 10 (10e) of the fifth embodiment, the number of legs included in the first leg group G1 and the number of legs included in the second leg group G2 are three. The field winding of any one of the plurality of motors M,... Is connected to the first leg group G1 as a first inductor L1 (L1a, L1b, L1c), and the second leg The field winding of any one of the remaining motors M,... Among the remaining motors M,... Is connected to the group G2 as a first inductor L1 (L1a, L1b, L1c).

  The electric drive device 10 (10e) includes a second opening / closing relay SWe that acts as second opening / closing means.

  The second open / close relay SWe includes a field winding (first inductor) between the first motor M (Ma) connected to the first leg group G1 and the second motor M (Mb) connected to the second leg group G2. The middle points of L1 (L1a, L1b, L1c) are electrically connected and disconnected. The second open / close relay SWe includes the middle point of the field winding of the first motor M (Ma) and the field winding of the second motor M (Mb) (first inductor L1 (L1a, L1b, L1c)). It is a relay switch that turns on and off current between points.

  Specifically, the electric drive device 10 (10e) of the fifth embodiment is similar to the three first inductors L1 (L1a, L1b, L1c) in the electric drive device 10 (10d) of the fourth embodiment shown in FIG. ), The three field windings of the existing first and second motors M (Ma, Mb) are respectively used, and the first, second and fifth to eighth switching relays SW1, SW2 are used. , SW5 to SW8 are removed, and a second opening / closing relay SWe is added. Although three field windings are used in each motor M here, one, two, or four or more field windings may be used depending on the configuration of the motor M.

  Specifically, the midpoint of each leg LG1, LG2, LG3 of the first leg group G1 and the three field windings (first inductor L1 (L1a, L1b, L1c)) in the first motor M (Ma). One end side is connected to each other, and the other end sides of the three field windings (first inductors L1 (L1a, L1b, L1c)) in the first motor M (Ma) are connected to each other. The midpoint of each leg LG6, LG5, LG4 of the second leg group G2, and one end side of the three field windings (first inductor L1 (L1a, L1b, L1c)) in the second motor M (Mb) Are connected, and the other end sides of the three field windings (first inductors L1 (L1a, L1b, L1c)) in the second motor M (Mb) are connected to each other.

  In the second open / close relay SWe, one first connection terminal T1 is connected to the other end of the three field windings (first inductors L1 (L1a, L1b, L1c)) in the first motor M (Ma). The other first connection terminal T2 of the three field windings (first inductors L1 (L1a, L1b, L1c)) in the second motor M (Mb) is connected to a connection point (midpoint) connected to each other. The other end side is connected to a connection point (middle point) connecting each other.

  In the electric drive device 10 (10e) of the fifth embodiment, when the storage battery BT is charged with electric power from the system PW, the first motor M (connected to the first leg group G1 by the second opening / closing relay SWe By conducting (closing) the middle point of the field winding (first inductor L1 (L1a, L1b, L1c)) between Ma) and the second motor M (Mb) connected to the second leg group G2 The existing first and second motors M (Ma, Mb) can be used as the first inductor L1 (L1a, L1b, L1c), and the cost can be reduced accordingly.

  In the electric drive device 10 (10e) of the fifth embodiment, the configuration in which the first and second open / close relays SWa and SWe and the third and fourth switching relays SW3 and SW4 are automatically operated is the same as that of the fourth embodiment. The configuration is the same.

[Sixth Embodiment]
FIG. 9 is a circuit diagram showing a schematic configuration in a regeneration (charging) mode of the sixth embodiment in the electric working machine 100 shown in FIG. The configuration on the first inductor L1 side of the sixth embodiment is the same as the configuration of the first embodiment shown in FIG.

  As shown in FIG. 9, in the electric drive device 10 (10f) of the sixth embodiment, the number of legs included in the third leg group G3 and the number of legs included in the fourth leg group G4 are two or more ( 3 here) and the same number, and 2 or more (here, one end side is connected to the middle point of 2 or more (here 3) legs in the third and fourth leg groups G3 and G4, respectively) Then, the other ends of the three second inductors L2 are connected to each other.

  Specifically, the electric drive device 10 (10f) of the sixth embodiment is different from the electric drive device 10 (10a) of the first embodiment shown in FIG. 3 in that the second inductor L2 is replaced with six second inductors L2 ( L2a, L2b, L2c, L2a, L2b, L2c), and the ninth to twelfth switching relays SW9 to SW12 are added.

  Specifically, the third, ninth, and tenth switching relays SW3, SW9, SW10 are respectively connected to the second connection terminals T3, T3, which are connected to the midpoints of the legs LG7, LG8, LG9 of the third leg group G3. The motor M connected to the second connection terminals T4, T4, T4 connected to the other end side of the second inductor L2 (L2a, L2b, L2c) and the third leg group G3 with respect to T3 (common terminal). The changeover switch for switching the connection terminals Tm, Tm, and Tm connected to each phase.

  Further, the fourth, eleventh and twelfth switching relays SW4, SW11, SW12 are respectively connected to the second connection terminals T3, T3, T3 connected to the midpoints of the legs LG12, LG11, LG10 of the fourth leg group G4. (Common terminal), the second connection terminals T4, T4, T4 connected to the other end of the second inductor L2 (L2a, L2b, L2c) and the motor M connected to the fourth leg group G4 It is a changeover switch that switches connection terminals Tm, Tm, Tm connected to each phase.

  Further, one end side of the second inductor L2 (L2a, L2b, L2c) connected to the third leg group G3 is connected to one side of the system PW via the connection terminal Ta, and is connected to the fourth leg group G3. One end side of the second inductor L2 (L2a, L2b, L2c) is connected to the other side of the system PW via a connection terminal Tb.

  In the electric drive device 10 (10f) of the sixth embodiment, the second inductor L2 is arranged at the midpoint between the legs (LG7, LG8, LG9) and (LG12, LG11, LG10) in the third and fourth leg groups G3, G4. Since the other ends of (L2a, L2b, L2c) and L2 (L2a, L2b, L2c) are connected, the power capacity for charging the rechargeable battery BT can be increased accordingly.

  The electric drive device 10 (10f) of the sixth embodiment automatically operates the first open / close relay SWa, the first to fourth and ninth to twelfth switching relays SW1 to SW4, SW9 to SW12. ing.

  Specifically, when detecting the non-charge state, the control device 20 turns on the first opening / closing relay SWa, and switches the first to fourth and ninth to twelfth switching relays SW1 to SW4 and SW9 to SW12. It is set as the structure switched to the motor M and ... side. On the other hand, when detecting the charging state, the control device 20 turns off the first open / close relay SWa, switches the first and second switching relays SW1 and SW2 to the first inductor L1 side, and performs the third, fourth and The ninth to twelfth switching relays SW3, SW4, SW9 to SW12 are switched to the system PW side.

  In the electric drive device 10 (10f) having such a configuration, when the storage battery BT is charged with electric power from the system PW, the first open / close relay SWa, the first to fourth, and the ninth to twelfth switching relays SW1 to SW4. , SW9 to SW12 can be automatically operated, and the operability by the user can be improved accordingly.

  The first open / close relay SWa and the first to fourth and ninth to twelfth switching relays SW1 to SW4 and SW9 to SW12 operate automatically by the connection detection means, but the automatic operation by the connection detection means. Instead of or in addition, the non-charged state and the charged state may be artificially switched by a user's manual operation.

[Seventh Embodiment]
FIG. 10 is a circuit diagram showing a schematic configuration in a regeneration (charging) mode of the seventh embodiment in the electric working machine 100 shown in FIG. The configuration of the seventh embodiment on the first inductor L1 side is the same as the configuration of the sixth embodiment shown in FIG.

  In the electric drive device 10 (10g) of the seventh embodiment, as shown in FIG. 10, the number of legs included in the third leg group G3 and the number of legs included in the fourth leg group G4 are set to 3. , The field winding of any one of the plurality of motors M,... Is connected as the second inductor L2 (L2a, L2b, L2c) to the third leg group G3, and the fourth leg The field winding of any one of the remaining motors M,... Of the fourth motor M (Md) is connected to the group G4 as a second inductor L2 (L2a, L2b, L2c).

  A field winding (second inductor L2 (L2a, L2b) between the third motor M (Mc) connected to the third leg group G3 and the fourth motor M (Md) connected to the fourth leg group G4. , L2c)) is connected to the system PW via the second connection terminals T3 and T4.

  Specifically, the electric drive device 10 (10g) of the seventh embodiment is similar to the six second inductors L2 (L2a, L2b, L2c) in the electric drive device 10 (10f) of the sixth embodiment shown in FIG. , L2a, L2b, L2c), the three field windings of the existing third and fourth motors M (Mc, Md) are used respectively. 12 switching relays SW3, SW4, SW9 to SW12 are removed. Although three field windings are used in each motor M here, one, two, or four or more field windings may be used depending on the configuration of the motor M.

  Specifically, the midpoint of each leg LG7, LG8, LG9 of the third leg group G3 and three field windings (second inductors L2 (L2a, L2b, L2c)) in the third motor M (Mc). One end side is connected to each other, and the other end sides of the three field windings (second inductors L2 (L2a, L2b, L2c)) in the third motor M (Mc) are connected to each other. The midpoint of each leg LG12, LG11, LG10 of the fourth leg group G4, and one end side of three field windings (second inductors L2 (L2a, L2b, L2c)) in the fourth motor M (Md) Are connected, and the other end sides of the three field windings (second inductors L2 (L2a, L2b, L2c)) in the fourth motor M (Md) are connected to each other.

  In the system PW, one side is a connection point (middle point) where the other end sides of the three field windings (second inductors L2 (L2a, L2b, L2c)) in the third motor M (Mc) are connected to each other. Are connected to each other via one second connection terminal T3, and the other side is connected to the other end of the three field windings (second inductors L2 (L2a, L2b, L2c)) of the fourth motor M (Md). It is connected to the connected connection point (middle point) via the other second connection terminal T4.

  In the electric drive device 10 (10g) of the seventh embodiment, the third motor M (Mc) connected to the third leg group G3 and the fourth motor M (Md) connected to the fourth leg group G4. Since the middle point of the field winding (second inductor L2 (L2a, L2b, L2c)) is connected to the system PW, the existing third and fourth motors M (Mc, Md) are connected to the second inductor L2 ( L2a, L2b, L2c, Lda, L2b, and L2c), and the cost can be reduced accordingly.

[Eighth Embodiment]
FIG. 11 schematically shows the winding state of the third and fourth motors M (Mc1, Md1) provided in the electric drive device 10 (10h) of the eighth embodiment in the electric working machine 100 shown in FIG. It is a circuit diagram. In FIG. 11, the third motor M (Mc1) and the fourth motor M (Md1) have the same configuration and are therefore shown in one figure.

  As shown in FIG. 11, the third and fourth motors M (Mc1, Md1) of the eighth embodiment are extended from the motor rotating field winding Wm (Wma, Wmb, Wmc) and are wound by a single transformer TR1. The first additional winding motor has a first field winding W1 (W1a, W1b, W1c) wound so as to constitute a part of the first winding. That is, the motor rotation field winding Wm (Wma, Wmb, Wmc) and the first field winding W2 (W1a, W1b, W1c) are wound in series.

  Specifically, the electric drive device 10 (10h) of the eighth embodiment is similar to the existing third and fourth motors M (Mc, Mc) in the electric drive device 10 (10g) of the seventh embodiment shown in FIG. Md) is a first additional winding motor M (Mc1, Md1) that is connected as a single-winding transformer TR1 that shares a part of the winding between the primary side and the secondary side.

  Specifically, in the first additional winding motor M (Mc1, Md1), the connection lines between the motor rotating field winding Wm (Wma) and the first field winding W1 (W1a) are third and The connection line between the motor winding field winding Wm (Wmb) and the first field winding W1 (W1b) is connected to the middle point of the legs LG7, LG12 of the four leg group G3, G4. A connection line between the motor winding field winding Wm (Wmc) and the first field winding W1 (W1c) is connected to the midpoint of the legs LG8, LG11 of the fourth leg group G3, G4. And connected to the midpoint of the legs LG9, LG10 of the fourth leg group G3, G4. Further, the first field winding W1 (W1a, W1b, W1c) is connected to the three connection terminals Tc, Td, Te, respectively, and the motor rotation field winding Wm (Wma, Wmb, Wmc) is connected. It is connected to the terminal Tf.

  The first field winding W1 (W1a, W1b, W1c) constitutes a second inductor L2 (L2a, L2b, L2c).

  In the electric drive device 10 (10h) of the eighth embodiment, even when the rated voltage of the inverter 11 in the third and fourth leg groups G3 and G4 does not correspond to the voltage of the system PW, the electric power from the system PW is generated. In addition, the existing first additional winding motor M (Mc1, Md1) can be used as a single-winding transformer TR1 in which a part of the winding is shared between the primary side and the secondary side. Therefore, cost reduction can be realized.

  In the eighth embodiment, for example, when the connection terminal Tc and the connection terminal Td are connected to the system PW, the connection can be made to correspond to a single-phase two-wire 200V power system and connected to the connection terminal Te. When the terminal Tf is connected to the system PW, it can correspond to a single-phase two-wire 100V power system, and the connection terminal Tc, the connection terminal Td, and the connection terminal Te are connected to the system PW. Can correspond to a three-phase three-wire 200V power system. Further, when the connection terminal Tc, the connection terminal Td, the connection terminal Te, and the connection terminal Tf are connected to the system PW, it is possible to correspond to a three-phase four-wire 200V power system. The same applies to the ninth embodiment described later.

[Ninth Embodiment]
FIG. 12 schematically shows the winding state of the third and fourth motors M (Mc2, Md2) provided in the electric drive device 10 (10i) of the ninth embodiment in the electric working machine 100 shown in FIG. It is a circuit diagram. In FIG. 11, the third motor M (Mc2) and the fourth motor M (Md2) have the same configuration, and thus are shown in one figure.

  As shown in FIG. 12, the third and fourth motors M (Mc2, Md2) of the ninth embodiment are part of the compound winding transformer TR2 together with the motor winding field winding Wm (Wma, Wmb, Wmc). The second additional winding motor having the second field winding W2 (W2a, W2b, W2c) wound so as to constitute That is, the motor rotation field winding Wm (Wma, Wmb, Wmc) and the motor rotation field winding Wm (Wma, Wmb, Wmc) are electrically insulated from each other. (W2a, W2b, W2c) are wound close to each other.

  Specifically, the electric drive device 10 (10i) of the ninth embodiment is similar to the existing third and fourth motors M (Mc, Mc) in the electric drive device 10 (10g) of the seventh embodiment shown in FIG. Md) is a second additional winding motor M (Mc2, Md2) configured as a compound transformer TR2 that is electrically insulated from the primary side and the secondary side.

  Specifically, in the second additional winding motor M (Mc2, Md2), one end of the motor rotation field winding Wm (Wma) is at the midpoint of the legs LG7, LG12 of the third and fourth leg groups G3, G4. One end of the motor rotation field winding Wm (Wmb) is connected to the midpoint of the legs LG8, LG11 of the third and fourth leg groups G3, G4, and the motor rotation field winding Wm (Wmc) Are connected to the midpoints of the legs LG9, LG10 of the third and fourth leg groups G3, G4, and the other ends of the motor rotation field windings Wm (Wma, Wmb, Wmc) are connected to each other. Yes. Further, one end side of the second field winding W2 (W2a, W2b, W2c) is connected to the three connection terminals Tc, Td, Te, respectively, and the second field winding W2 (W2a, W2b, W2c) The other end side is connected to the connection terminal Tf.

  The second field winding W2 (W2a, W2b, W2c) constitutes a second inductor L2 (L2a, L2b, L2c).

  In the electric drive device 10 (10i) of the ninth embodiment, even when the rated voltage of the inverter 11 in the third and fourth leg groups G3 and G4 does not correspond to the voltage of the system PW, the electric power from the system PW is generated. In addition, the existing second additional winding motor M (Mc2, Md2) can be diverted as a double-winding transformer TR2 that is electrically insulated from the primary side and the secondary side. Cost reduction can be realized and safety can be improved.

[Tenth embodiment]
By the way, when charging the storage battery BT with the electric power from the single-phase system PW, the bidirectional buck-boost DC-DC converter 12 configured by the first and second leg groups G1, G2 and the first inductor L1 (FIG. 13). It is preferable that the current Idc flowing on the system PW side of the reference (P) is a sine wave current in phase with the voltage waveform of the system PW. However, the inverters 11, 11, and 11 are respectively provided together with the second leg group G2 constituting the system PW side of the bidirectional buck-boost DC-DC converter 12 and the third and fourth leg groups G3 and G4 connected to the system PW. Capacitances (total of DC-side capacitors Cb, Cc, Cd in this case) of several hundreds μF or more are obtained by synthesizing constituent capacitors Cb, Cc, Cd (hereinafter referred to as DC-side capacitors Cb, Cc, Cd). ) Since it is large, the DC side capacitors Cb, Cc, and Cd are the boundaries, and the system PW side and the bidirectional buck-boost DC-DC converter 12 side are electrically separated. Then, since the current Idc flowing to the system PW side cannot be controlled by the bidirectional buck-boost type DC-DC converter 12, it is difficult to make the current Idc a sine wave current in phase with the voltage waveform of the system PW.

  FIG. 13 is a circuit diagram showing a schematic configuration in a regeneration (charging) mode of the tenth embodiment in the electric working machine 100 shown in FIG.

  In this regard, as shown in FIG. 13, the electric drive device 10 (10j) of the tenth embodiment is a bidirectional step-up / step-down DC− configured by the first and second leg groups G1, G2 and the first inductor L1. The combined capacitance of the DC side capacitors Cb, Cc, Cd is such that the current Idc flowing to the system PW side of the bidirectional buck-boost type DC-DC converter 12 can be controlled by the DC converter 12. The configuration is 100 μF or less. Such a configuration can be applied to any of the circuit configurations of the first to ninth embodiments, but here, the circuit configuration of the first embodiment will be described as an example.

  Specifically, in the electric drive device 10 (10j) of the tenth embodiment, two open / close relays SWb, SWc, and SWd are added to the electric drive device 10 (10a) of the first embodiment shown in FIG. It is supposed to be.

  Specifically, the open / close relays SWb, SWc, SWd are electrically connected and disconnected between the second, third, and fourth leg groups G2, G3, G4 and the DC-side capacitors Cb, Cc, Cd, respectively. It is supposed to be. Here, the open / close relays SWb, SWc, SWd are respectively between the positive side of the DC side capacitors Cb, Cc, Cd and the positive side of the second, third, and fourth leg groups G2, G3, G4. It is connected.

  And in the electric drive device 10 (10j), when charging the storage battery BT with the electric power from the system PW, the second, third and fourth leg groups G2, G3, G4 by the open / close relays SWb, SWc, SWd. And the DC side capacitors Cb, Cc, Cd are electrically disconnected (opened) to control the current Idc flowing in the system PW side of the bidirectional buck-boost DC-DC converter 12 in the first leg group. This is performed by G1 or the second leg group G2.

  Further, the electric drive device 10 (10j) automatically operates the open / close relays SWb, SWc, SWd.

  The control device 20 is configured to turn on the open / close relays SWb, SWc, SWd when a non-charge state is detected. On the other hand, the control device 20 is configured to turn off the open / close relays SWb, SWc, SWd when detecting the state of charge.

  In the electric drive device 10 (10j) having such a configuration, when the storage battery BT is charged with electric power from the system PW, the open / close relays SWb, SWc, SWd can be automatically operated, and the operation by the user accordingly. Can be improved.

  Note that the open / close relays SWb, SWc, SWd are operated by automatic operation by the connection detection means, but in an uncharged state instead of or in addition to the automatic operation by the connection detection means by a user's manual operation. And the state of charge may be artificially switched.

  Thus, in the electric drive device 10 (10j) of the tenth embodiment, when the storage battery BT is charged with the electric power from the system PW, the DC-side capacitors Cb, Cc, and Cd are combined (total). Since the capacitance is 100 μF or less, the bidirectional buck-boost DC-DC converter 12 can control the current Idc flowing to the system PW side of the bidirectional buck-boost DC-DC converter 12. Thus, the current Idc can be made a sine wave current in phase with the sine waveform of the current Iac flowing through the system PW.

  Incidentally, the bidirectional buck-boost DC-DC converter 12 includes the first inductor L1 as an energy storage element that stores energy. For example, the storage battery BT and the DC-side capacitor Cb, When the operation mode that is not electrically connected to both Cc and Cd cannot be realized, the bidirectional buck-boost DC-DC converter 12 causes the bidirectional buck-boost DC-DC converter 12 to connect to the system PW side. Even if the current Idc flowing through the storage battery BT can be controlled, the current Ibat supplied to the storage battery BT cannot be controlled, so that a pulsating current having a frequency corresponding to the frequency of the system PW flows through the storage battery BT. If it does so, the heat_generation | fever of the internal resistance (not shown) in the storage battery BT will show the tendency to become large, and not only cannot charge the storage battery BT efficiently, but it will cause the lifetime reduction of the storage battery BT.

  For example, if the frequency of the system PW is θ, the effective values of the voltage and current on the system PW side are Vdc and Idc, and the voltage of the storage battery BT is Vbat, the pulsating current flowing in the storage battery BT is (Vdc × Idc−Vdc × Idc × cos (2 × 2πθ)) / Vbat.

  In order to reduce this pulsating current, it can be considered that a filter for reducing the pulsating current is provided instead of a filter for smoothing the on / off waveform at the switching frequency. Since the frequency is twice as low as the frequency θ of the system PW (for example, 60 Hz) (for example, 2θ = 120 Hz), the physical size is such that it cannot be used in a recent apparatus configuration that requires downsizing. (Size) and cannot be used in practice.

  In this regard, the first to ninth embodiments are configured to realize an operation mode in which the first inductor L1 is not electrically connected to both the storage battery BT and the DC-side capacitors Cb, Cc, Cd. .

  That is, the electric drive device 10 (10a to 10i) of the first to ninth embodiments generates the pulsating power that can be generated when charging the storage battery BT between the first leg group G1 and the second leg group G2. It accumulates in the first inductor L1 connected to.

(Control of current flowing to the system side by the first leg group or the second leg group)
FIG. 14 shows both of the first and second leg groups G1, G2 and the first inductor L1 when the storage battery BT is charged with power from the system PW in the electric drive device 10 according to the present embodiment. 2 is a circuit diagram showing a schematic configuration of a step-up / down type DC-DC converter 12. FIG. In FIG. 14, the reference numerals of the semiconductor switches constituting the switching elements sw1, sw2, sw11, sw12 are S1, S2, S3, S4, and the reference numerals of the diodes constituting the switching elements sw1, sw2, sw11, sw12 are D1, D2, D3, and D4. In the following description, the switching elements sw1, sw2, sw11, and sw12 are referred to as first to fourth switching elements sw1, sw2, sw11, and sw12, respectively.

  A bidirectional buck-boost DC-DC converter (hereinafter simply referred to as a DC-DC converter) 12 shown in FIG. 14 performs control of the current Idc flowing to the system PW side and control of the current Ibat supplied to the storage battery BT. It can be done independently. Thereby, the control apparatus 20 can control the electric current Ibat supplied to the storage battery BT, controlling the electric current Idc which flows into the system | strain PW side.

  That is, the first switching element sw1 includes the first semiconductor switch S1 and the first diode D1. The first semiconductor switch S1 is a semiconductor device capable of controlling current on / off only in one direction. The first diode D1 is connected in parallel to the first semiconductor switch S1 so that the current can flow in a direction opposite to the direction in which the first semiconductor switch S1 can control on and off of the current.

  The second switching element sw2 includes a second semiconductor switch S2 and a second diode D2. The second semiconductor switch S2 is a semiconductor device that can control current on / off only in one direction. The second diode D2 is connected in parallel to the second semiconductor switch S2 so that the current can flow in a direction opposite to the direction in which the second semiconductor switch S2 can control on and off of the current.

  The third switching element sw11 includes a third semiconductor switch S3 and a third diode D3. The third semiconductor switch S3 is a semiconductor device that can control current on / off only in one direction. The third diode D3 is connected in parallel to the third semiconductor switch S3 so that the current can flow in a direction opposite to the direction in which the third semiconductor switch S3 can control on and off of the current.

  The fourth switching element sw12 includes a fourth semiconductor switch S4 and a fourth diode D4. The fourth semiconductor switch S4 is a semiconductor device that can control current on / off only in one direction. The fourth diode D4 is connected in parallel to the fourth semiconductor switch S4 so that the current can flow in a direction opposite to the direction in which the fourth semiconductor switch S4 can control on and off of the current.

  The first inductor L1 has one end connected to the anode side of the first diode D1 included in the first switching element sw1 and the cathode side of the second diode D2 included in the second switching element sw2, and the other end connected to the first inductor L1. The third diode D3 included in the third switching element sw11 is connected to the anode side of the third diode D3 and the cathode side of the fourth diode D4 included in the fourth switching element sw12.

  The DC-DC converter 12 has the positive electrode of the storage battery BT connected to the cathode side of the first diode D1 included in the first switching element sw1, and the anode side of the second diode D2 included in the second switching element sw2. Is connected to the negative electrode of the storage battery BT.

  The DC-DC converter 12 includes the third diode D3 included in the third switching element sw11 on the cathode side of the third and fourth legs G3 and G4, and is included in the fourth switching element sw12. The negative electrode side of the third and fourth legs G3, G4 is connected to the anode side of the fourth diode D4.

  The control device 20 is configured to control the switching operation of the first to fourth switching elements sw1, sw2, sw11, sw12 of the DC-DC converter 12.

  In the DC-DC converter 12, as the operation modes indicating the ON state and the OFF state of the first to fourth switching elements sw1, sw2, sw11, sw12, the following first operation mode to fourth operation mode operating in the power running mode are used. The following fifth operation mode to eighth operation mode that operates in the regeneration mode can be exemplified.

  FIG. 15 is an explanatory diagram for explaining an operation example in which the DC-DC converter 12 shown in FIG. 14 is operated in the power running mode. In FIG. 15, “◯” indicates a switching target. The same applies to FIG. 16 described later.

  As shown in FIG. 15, the first operation mode is a mode in which the first and fourth switching elements sw1 and sw12 are turned on, and the other second and third switching elements sw2 and sw11 are turned off. The second operation mode is a mode in which the first switching element sw1 is turned on and the other second, third, and fourth switching elements sw2, sw11, sw12 are turned off. The third operation mode is a mode in which the first to fourth switching elements sw1, sw2, sw11, sw12 are all turned off. The fourth operation mode is a mode in which the fourth switching element sw12 is turned on and the other first, second, and third switching elements sw1, sw2, and sw11 are turned off.

  When the control device 20 executes the power running mode, the control device 20 performs the first to fourth in accordance with the magnitude relationship between the output voltage Vdc from the third and fourth legs G3 and G4 and the output voltage Vbat from the storage battery BT. Various switching operations are performed to switch at least two of the operation modes at a short switching frequency (for example, any switching frequency of about 10 kHz to 100 kHz).

  For example, when performing the step-up operation (Vbat <Vdc) in which the output voltage Vdc is larger than the output voltage Vbat, the control device 20 performs an operation of alternately switching between the first operation mode and the second operation mode. When the step-down operation (Vbat> Vdc) in which the output voltage Vbat is larger than the output voltage Vdc is performed, an operation for alternately switching between the second operation mode and the third operation mode is performed. Step-up operation (Vbat <Vdc), step-down operation (Vbat> Vdc), or step-up / step-down operation in which the output voltage Vdc and the output voltage Vbat are substantially equal (Vbat≈Vdc: the absolute value of the difference between the voltage Vdc and the voltage Vbat is predetermined) When it is within the range), an operation of alternately switching between the first operation mode and the third operation mode can also be performed. Furthermore, when performing a pulsation reducing operation described later, an operation of sequentially switching any one of the first to fourth operation modes is performed.

  FIG. 16 is an explanatory diagram for explaining an operation example in which the DC-DC converter 12 shown in FIG. 14 is operated in the regeneration (charging) mode. FIG. 17 is a graph showing an example of specific operation waveforms when the DC-DC converter 12 shown in FIG. 14 is operated in the regeneration (charging) mode.

  As shown in FIG. 16, the fifth operation mode is a mode in which the second and third switching elements sw2 and sw11 are turned on and the other first and fourth switching elements sw1 and sw12 are turned off. The sixth operation mode is a mode in which the third switching element sw11 is turned on and the other first, second, and fourth switching elements sw1, sw2, and sw12 are turned off. The seventh operation mode is a mode in which the first to fourth switching elements sw1, sw2, sw11, sw12 are all turned off. The eighth operation mode is a mode in which the second switching element sw2 is turned on and the other first, third, and fourth switching elements sw1, sw11, and sw12 are turned off.

  When the control device 20 executes the regeneration (charge) mode, the control device 20 determines whether the output voltage Vdc from the third and fourth legs G3 and G4 and the output voltage Vbat from the storage battery BT are in the fifth magnitude relationship. To the eighth operation mode, various switching operations for switching at least two modes at a short switching frequency (for example, any switching frequency of about 10 kHz to 100 kHz) are performed.

  For example, when performing the step-up operation (Vbat> Vdc) in which the output voltage Vbat is larger than the output voltage Vdc (see α1 in FIG. 17), the control device 20 alternately switches between the fifth operation mode and the sixth operation mode. Perform the action. When performing a step-down operation (Vbat <Vdc) in which the output voltage Vdc is larger than the output voltage Vbat (see α2 in FIG. 17), an operation of alternately switching between the sixth operation mode and the seventh operation mode is performed. Step-up operation (Vbat> Vdc), step-down operation (Vbat <Vdc), or step-up / step-down operation in which the output voltage Vdc and the output voltage Vbat are substantially equal (Vbat≈Vdc: the absolute value of the difference between the voltage Vdc and the voltage Vbat is predetermined) When it is within the range (see α3 in FIG. 17), it is also possible to perform an operation of alternately switching between the fifth operation mode and the seventh operation mode. Furthermore, when performing a pulsation reducing operation described later, an operation of sequentially switching any one of the fifth to eighth operation modes is performed.

  Note that the control device 20 can detect the output voltage Vdc and the output voltage Vbat with a voltmeter (not shown).

[About pulsation reduction operation]
Next, the pulsation reducing operation will be described below by taking as an example a case where the storage battery BT is charged with electric power from the system PW.

  In the description of the pulsation reducing operation, an example of a switching operation within a certain switching period T (for example, 100 μsec when the switching frequency is 10 kHz) will be described.

FIG. 18 is a graph for explaining an example of the pulsation reducing operation. The upper diagram shows the current IL flowing through the first inductor L1, the target value Ibat ^* for controlling the current Ibat supplied to the rechargeable battery BT, and the target value Idc ^* for controlling the current Idc flowing to the system PW side ^. Is shown. The lower diagram shows an example of the switching operation within a certain switching period T.

As shown in FIG. 18, within a certain switching period T, the control device 20 determines the first time T1 [= (Idc ^* / IL) expressed as a ratio of the target value Idc ^* (see β1 in FIG. 18) to the current IL. ) × T], the sixth switching mode in which the third switching element sw11 is turned on and the first, second, and fourth switching elements sw1, sw2, and sw12 are turned off is performed, and then the target value Ibat for the current IL ^* from minus target value Idc ^* current at the second time T2, expressed as a percentage ^{[= ((Ibat * -Idc *} ) / IL) × T] time (.beta.2 see FIG. 18), first from the first 4 switching elements sw1, sw2, sw11, performs a seventh operation mode to turn off all sw12, then current obtained by subtracting the target value Ibat ^* from (current IL for the current IL (FIG. In 8 .beta.3 reference)) of third time T3 was expressed as a percentage ^{[= ((IL-Ibat *} ) / IL) × T] time, the second switching element sw2 is turned on, first, third and 4 The 8th operation mode which turns off switching element sw1, sw11, sw12 is performed.

FIG. 19 is a graph for explaining another example of the pulsation reducing operation. The upper diagram shows the current IL flowing through the first inductor L1, the target value Ibat ^* for controlling the current Ibat supplied to the rechargeable battery BT, and the target value Idc ^* for controlling the current Idc flowing to the system PW side ^. Is shown. The lower diagram shows an example of a switching operation within another switching period T.

As shown in FIG. 19, in another switching period T, the control device 20 turns on the third switching element sw11 for the first time T1 [= (Ibat ^* / IL) × T] time, The sixth operation mode for turning off the second and fourth switching elements sw1, sw2, and sw12 is performed, and then the second time T2 [= ((Idc ^* −Ibat ^* ) / IL) × T] time, And the third switching element sw2 and sw11 are turned on, the first and fourth switching elements sw1 and sw12 are turned off, and then the third time T3 [= ((IL-Idc ^* ) / IL ) × T] The eighth operation mode in which the second switching element sw2 is turned on and the first, third, and fourth switching elements sw1, sw11, and sw12 are turned off is performed.

  By performing the pulsation reducing operation in this manner, the current Idc flowing on the system PW side can be controlled to be a sine wave current in phase with the voltage waveform of the system PW (see FIG. 17) and supplied to the rechargeable battery BT. Since the current Ibat can be a constant current, a pulsating current having a frequency corresponding to the frequency of the system PW does not flow to the storage battery BT, and the constant current Ibat can easily flow. The storage battery BT can be charged efficiently, and the temperature rise of the storage battery BT can be prevented, thereby preventing the life of the storage battery BT from decreasing. In addition, it is only necessary to attach a filter for smoothing the ON / OFF waveform at the switching frequency (a filter having a size significantly smaller than the filter for reducing the pulsating current).

  Here, since the rechargeable battery BT is easily affected by the pulsating current when the charging current Ibat is large, the pulsation reducing operation is performed at the initial stage of charging (specifically, during a predetermined period from the start of charging). ) Is preferable.

[Other Embodiments]
(Rectifiers that are not switched)
In the electric drive device 10 (10a to 10j) of the first to tenth embodiments, the control device 20 does not switch the third leg group G3 and the fourth leg group G4 (for example, the legs LG7 and LG12) (passive). Can be operated as By doing so, the high frequency switching of the third leg group G3 and the fourth leg group G4 (for example, the legs LG7, LG12) can be stopped, and thereby the switching loss can be reduced, so that the power conversion efficiency is improved accordingly. Can do.

(About synchronous rectifiers to be switched)
Further, as the switching elements sw13 to sw24 of the third leg group G3 and the fourth leg group G4 (for example, the switching elements sw13, sw14, sw23, and sw24 of the legs LG7 and LG12), particularly when the switching elements sw13 to sw24 are turned on. In the case of a reverse conducting semiconductor element (specifically, a MOSFET reverse conducting semiconductor element) that exhibits linear voltage-current characteristics, the control device 20 includes switching elements sw13 to sw24 (for example, switching elements sw13, sw14, Sw23 and sw24) may be switched to operate as a synchronous rectifier.

  Hereinafter, the switching elements sw13, sw14, sw23, and sw24 of the third leg group G3 and the fourth leg group G4 will be described as an example.

  FIG. 20 is an explanatory diagram for explaining an advantage when the switching elements sw13, sw14, sw23, and sw24 of the third leg group G3 and the fourth leg group G4 are operated as a synchronous rectifier. FIG. 20A shows the switching elements sw13, sw14, sw23, and sw24 in the off state. FIG. 20B shows the current-voltage characteristics α of the switching elements sw13, sw14, sw23, sw24 in the off state. FIG. 20C illustrates the switching elements sw13, sw14, sw23, and sw24 in the on state. FIG. 20D shows the current-voltage characteristic β (solid line) of the switching elements sw13, sw14, sw23, sw24 in the on state in comparison with the current-voltage characteristic α (broken line) in the off state. That is, the switching elements sw13, sw14, sw23, and sw24 show nonlinear voltage-current characteristics in the off state and show linear voltage-current characteristics in the on-state.

  As shown in FIG. 20A, when the switching elements sw13, sw14, sw23, sw24 are operated as non-switching (passive) rectifiers, the non-linear current-voltage characteristic α shown in FIG. Increases rapidly when the voltage v is greater than about 0.7V. On the other hand, as shown in FIG. 20C, when the switching elements sw13, sw14, sw23, sw24 are operated as synchronous rectifiers that are switched synchronously when the current i flows, the linear current shown in FIG. -In the voltage characteristic β, the current i and the voltage v have a positive proportional relationship.

  That is, when the voltage v is smaller than the voltage Vc at the point γ where the nonlinear current-voltage characteristic α and the linear current-voltage characteristic β intersect, the power Wb [= Vb × Ia] is smaller than power Wa [= Va (> Vb) × Ia] in the off state (power Wb <power Wa).

  Therefore, when the switching elements sw13, sw14, sw23, and sw24 are switched to operate as a synchronous rectifier, the power conversion efficiency can be improved as compared with the case where the switching elements sw13, sw14, sw23, and sw24 are operated as a non-switching (passive) rectifier.

(About the use of surplus legs)
Moreover, in the electric drive device 10 (10a to 10j) of the first to tenth embodiments, the solar cell PV (see FIG. 21) is connected to the surplus leg among the legs included in the plurality of inverters 11. And the control apparatus 20 may be set as the structure which can charge storage battery BT with the electric power from the solar cell PV.

  Such a configuration can be applied to any of the circuit configurations of the first to tenth embodiments. Here, the circuit configuration of the first embodiment will be described as an example.

  FIG. 21 is a circuit diagram illustrating a state in which the solar cell PV is connected to an excess leg in the electric drive device 10 (10a) of the first embodiment.

  As shown in FIG. 21, the solar cell PV is connected to a surplus leg (here, the leg LG <b> 11) among the legs included in the plurality of inverters 11. Specifically, one end side of the solar cell PV is connected to the midpoint of the leg LG11, and the other end side of the solar cell PV is connected to the negative electrode side of the fourth leg G4. And the control apparatus 20 charges the storage battery BT with the electric power from the solar cell PV by switching each relay and each leg.

  In this configuration, the surplus leg LG11 to which the solar cell PV is connected can be used for charging the storage battery BT with the electric power from the solar cell PV, whereby the surplus leg LG11 can be effectively utilized. it can.

(About switching pulsation)
By the way, the 4th and 4th shown in FIG.7 and FIG.8 by which the 1st and 2nd leg group G1, G2 and the 1st inductor L1 are set as the structure which implement | achieves the switching control of the electric power of multiple phases (here 3 phases). In the fifth embodiment, it is desirable to consider the effects of switching pulsations. In the sixth and seventh embodiments shown in FIGS. 9 and 10, the third and fourth leg groups and the second inductor L2 are configured to realize switching control of three-phase power. It is desirable to consider the impact.

  FIG. 22 is a diagram of the leg groups G1 and G3 in the case where the three-phase power switching control is realized as in the circuit configurations shown in the fourth and fifth embodiments and the sixth and seventh embodiments. A graph is shown when only the three switching elements (sw2, sw4, sw6) and (sw14, sw16, sw18) of the arm are switched at the same timing. In each graph shown in FIG. 22, the fourth and fifth embodiments and the sixth and seventh embodiments are represented by one diagram for the sake of simplicity. The same applies to FIG. 23 described later. In the following description, the switching elements sw2 and sw14 are simply referred to as a switching element AN, the switching elements sw4 and sw16 are simply referred to as a switching element BN, the switching elements sw6 and sw18 are simply referred to as a switching element CN, and the switching elements sw1, The sw13 is simply referred to as a switching element AP, the switching elements sw3 and sw15 are simply referred to as a switching element BP, and the switching elements sw5 and sw17 are simply referred to as a switching element CP. The currents IL1a and IL2a flowing through the first and second inductors L1a and L2a are simply referred to as current ILa, the currents IL1b and IL2b flowing through the first and second inductors L1b and L2b are simply referred to as current ILb, and the first and second The currents IL1c and IL2c flowing through the two inductors L1c and L2c are simply referred to as current ILc.

  FIG. 22A shows temporal changes in the switching timing of the switching elements AN, BN, and CN. Note that the switching elements AP, BP, and CP are turned off.

  FIG. 22B shows temporal changes in currents ILa, ILb, and ILc flowing through the first and second inductors (L1a, L1b, L1c) and (L2a, L2b, L2c).

  FIG. 22C shows temporal changes in the currents IAP, IBP, and ICP flowing through the switching elements AP, BP, and CP when the switching elements AN, BN, and CN are switched (on / off).

  FIG. 22D shows the current Ibat supplied to the storage battery BT when the switching elements AN, BN, CN are switched (ON / OFF) and the current Idc flowing through the DC side capacitors Cb, Cc, Cd on the system PW side. This shows the change over time.

  As shown in FIG. 22, in the circuit configurations as shown in the fourth and fifth embodiments and the sixth and seventh embodiments, the switching elements AN, BN, CN are switched at the same timing, so that the storage battery BT The pulsation of the current Ibat supplied to becomes larger.

  From this viewpoint, it is preferable that the control device 20 switches the legs LG to LG6 in the first and second leg groups G1 and G2 so that the phases of the three-phase powers are shifted (preferably evenly shifted). The control device 20 preferably switches the legs LG7 to LG12 in the third and fourth leg groups G3 and G4 so that the phases of the three-phase powers are shifted (preferably evenly shifted).

  FIG. 23 is a diagram showing a lower group of leg groups G1 and G3 in the case where the switching control of the three-phase power is realized as in the circuit configurations shown in the fourth and fifth embodiments and the sixth and seventh embodiments. A graph is shown when only the three switching elements AN, BN, and CN of the arm are switched at different timings.

  FIG. 23A shows temporal changes in the switching timing of the switching elements AN, BN, and CN. FIG. 23B shows temporal changes in the currents ILa, ILb, and ILc flowing through the first and second inductors (L1a, L1b, L1c), (L2a, L2b, L2c) (leg group G1 and leg). The direction toward the group G3 is assumed to be a positive direction and is assumed to be a constant value). FIG. 23 (c) shows temporal changes in the current flowing through the switching elements AP, BP, CP when the switching elements AN, BN, CN are switched (on / off). FIG. 23D shows the time of the current Ibat supplied to the storage battery BT when the switching elements AN, BN, CN are switched (ON / OFF) and the current Idc flowing through the DC side capacitors Cb, Cc, Cd on the system PW side. Changes.

  Here, three switching elements (sw2, sw4, sw6) and (sw14, sw16, sw18) of the lower arm in the leg groups G1 and G3 have been described as examples, but the same applies to other switching elements. Can do.

  As shown in FIG. 23, the phases of the three-phase electric power are shifted between the legs LG1 to LG6 in the first and second leg groups G1 and G2 and the legs LG7 to LG12 in the third and fourth leg groups G3 and G4. Switching pulsation can be reduced by switching to.

  Thus, in the fourth and fifth embodiments shown in FIGS. 7 and 8, the high frequency ripple flowing into the electrolytic capacitor (not shown) provided on the storage battery BT side is reduced, and the life of the electrolytic capacitor is extended. In addition to this, it is possible to reduce the physical size (size) of the filter for reducing the pulsating current flowing in the storage battery BT due to switching pulsation. In the sixth and seventh embodiments shown in FIGS. 9 and 10, the high frequency ripple flowing into the DC side capacitors Cb, Cc, Cd (electrolytic capacitors) provided on the system PW side is reduced to reduce the DC side capacitors Cb, Cc. , Cd can be extended, and the physical size (size) of a filter (not shown) for reducing the pulsating current flowing through the system PW due to switching pulsation can be reduced.

  In the circuit configurations shown in the fourth and fifth embodiments and the sixth and seventh embodiments, a relatively small power capacity (for example, about one third of the rated power of the inverter 11) can be allowed by design. In the fourth and fifth embodiments, it is preferable to switch only one of the plurality of legs LG1 to LG6 in the first and second leg groups G1 and G2. In the sixth and seventh embodiments, it is preferable to switch only one of the plurality of legs LG7 to LG12 in the third and fourth leg groups G3 and G4. By doing so, the switching loss can be reduced as compared with the case where each leg is switched, so that the power conversion efficiency can be improved accordingly. Furthermore, it is preferable to switch the leg to be switched based on the switching device temperature of the leg and the integrated value of the current flowing through the leg so as not to exceed a preset threshold value. In this way, the temperature rise of the element can be prevented as compared with the case where the same leg is continuously switched, and the switching loss and conduction loss of the element can be reduced, thereby further improving the power conversion efficiency. Can be improved.

  The electric drive device 10 described above is applicable to any electric work machine driven by a storage battery, such as a construction work machine such as a tractor, an excavator, a wheel loader or a carrier, or an agricultural work machine such as a tiller or a rice transplanter. can do.

DESCRIPTION OF SYMBOLS 10 Electric drive device 11, ... Several inverter 12 Bidirectional buck-boost type DC-DC converter 20 Control apparatus 100 Electric working machine BT Storage battery (an example of an electrical storage element)
C (Ca to Cd) Capacitors Cb, Cc, Cd DC side capacitor D Diodes G1 to G4 First to fourth leg groups Gn Connection leg group L1 First inductor L2 Second inductors LG1 to LG12 Leg M,. Ma 1st motor Mb 2nd motor Mc 3rd motor Md 4th motor PV Solar battery PW Commercial power system (an example of an external power supply)
S semiconductor switch SW1-SW12 switching relay SWa 1st opening / closing relay (an example of 1st opening / closing means)
SWe second open / close relay (an example of second open / close means)
SWb switching relay SWc switching relay SWd switching relays sw1 to sw24 switching elements T1, T2 first connection terminals T3, T4 second connection terminal W1 first field winding W2 second field winding Wm motor winding field winding

Claims (20)

An electric working machine provided with an electric drive device having a plurality of inverters each supplied with the same DC voltage from a storage element and driving a plurality of motors,
The electric drive device is configured to store the electric power storage at both ends of first to fourth leg groups obtained by dividing individual legs included in the plurality of inverters into four leg groups each having one or more legs. A first electrical connection and disconnection between the first leg group to which the elements are connected and the connection leg group configured by the fourth leg group from the second leg group to which both ends are respectively connected. A first connection terminal that includes an opening / closing means and connects a first inductor between a midpoint of at least one leg of the first leg group and a midpoint of at least one leg of the second leg group; A second connection terminal connected to an external power source via a second inductor between the midpoint of at least one leg of the third leg group and the midpoint of at least one leg of the fourth leg group It is characterized by having Electric working machine to be. The electric working machine according to claim 1,
The electric drive device electrically shuts off the first leg group and the connection leg group by the first opening and closing means when charging the power storage element with electric power from the external power source, The first inductor is connected between the midpoint of at least one leg of one leg group and the midpoint of at least one leg of the second leg group, and at least one of the third leg group An electric work machine characterized in that a midpoint of a leg and a midpoint of at least one leg of the fourth leg group are connected to the external power source via the second inductor, respectively. . The electric working machine according to claim 1 or 2,
In the electric drive device, the second inductor between the third leg group and the fourth leg group forms a part of an autotransformer. The electric working machine according to claim 1 or 2,
In the electric drive apparatus, the second inductor between the third leg group and the fourth leg group constitutes a part of a compound winding transformer. The electric working machine according to any one of claims 1 to 4,
In the electric drive device, the number of legs included in the first leg group and the number of legs included in the second leg group are two or more and the same number, and the number of legs in the first leg group is two or more. Two or more said 1st inductors are respectively connected between the middle point and the middle point of two or more legs in the said 2nd leg group, The electric working machine characterized by the above-mentioned. The electric working machine according to any one of claims 1 to 4,
In the electric drive device, the number of legs included in the first leg group and the number of legs included in the second leg group are 3, and any one of the plurality of motors is included in the first leg group. One first motor is connected as the first inductor, and any one of the remaining motors is connected to the second leg group as the first inductor, and is connected to the first leg group. And a second opening / closing means for electrically connecting and disconnecting a middle point between field windings of the first motor and the second motor connected to the second leg group. Work machine. The electric working machine according to claim 6,
When the electric drive device charges the power storage element with electric power from the external power source, the second opening / closing means electrically connects between the middle points of the field windings of the first motor and the second motor. An electric working machine characterized in that the electric working machine is configured to be electrically connected. The electric working machine according to any one of claims 1 to 7,
In the electric drive device, the number of legs included in the third leg group and the number of legs included in the fourth leg group are two or more and the same number, and 2 in the third and fourth leg groups. The electric working machine characterized in that the other end sides of the two or more second inductors, each having one end side connected to the external power source, are respectively connected to the midpoint of the above legs. The electric working machine according to any one of claims 1 to 7,
In the electric drive device, the number of legs included in the third leg group and the number of legs included in the fourth leg group are 3, and any one of the plurality of motors is included in the third leg group. One third motor is connected as the second inductor, and any one of the remaining motors is connected to the fourth leg group as the second inductor and connected to the third leg group. An electric working machine characterized in that a middle point between field windings of the third motor and the fourth motor connected to the fourth leg group is connected to the external power source. The electric working machine according to claim 3,
At least one of the plurality of motors has a first additional winding having a first field winding that is extended from the field winding for motor rotation and wound to form a part of the autotransformer. It is a wire motor,
The electric drive device is configured such that the first additional winding motor is connected as the autotransformer. The electric working machine according to claim 4,
At least one of the plurality of motors includes a second additional winding motor having a second field winding wound so as to form a part of a multi-turn transformer together with a field winding for rotating the motor. Has been
The electric working machine is configured such that the second additional winding motor is connected as the compound winding transformer. The electric working machine according to any one of claims 1 to 11,
The electric drive device is configured such that a capacitance of a DC-side capacitor viewed from the second leg group, the third leg group, and the fourth leg group connected to the external power source is 100 μF or less, and The third leg group and the fourth leg group connected to an external power supply are operated as a rectifier that does not switch, and further, the first leg group or the second leg group has control of the current flowing to the external power supply side. An electric working machine characterized by being configured. The electric working machine according to any one of claims 1 to 11,
The electric drive device is configured such that a capacitance of a DC-side capacitor viewed from the second leg group, the third leg group, and the fourth leg group connected to the external power source is 100 μF or less, and The third leg group and the fourth leg group connected to an external power source are switched to operate as a synchronous rectifier, and the current flowing to the external power source side is controlled to the first leg group or the second leg group. An electric working machine characterized by having a structure to be provided. The electric working machine according to claim 12 or claim 13,
The electric drive device includes a DC-side capacitor viewed from the second leg group, the third leg group, and the fourth leg group connected to the external power source when the power storage element is charged with power from the external power source. The electric working machine is characterized in that the electrostatic capacity of the electric working machine is 100 μF or less. The electric working machine according to any one of claims 1 to 14,
The electric drive device is configured to accumulate pulsating power that can be generated when charging the power storage element in the first inductor connected between the first leg group and the second leg group. An electric working machine characterized by The electric working machine according to any one of claims 1 to 15,
The electric drive device is configured such that a solar cell is connected to a surplus leg among the legs included in the plurality of inverters, and the power storage element can be charged with electric power from the solar cell. Electric working machine. The electric working machine according to any one of claims 1 to 16,
The first and second leg groups and the first inductor are configured to realize switching control of a plurality of phases of power,
The electric working device is configured to switch a plurality of legs in the first and second leg groups so that phases of the plurality of phases of electric power are shifted. The electric working machine according to any one of claims 1 to 16,
The first and second leg groups and the first inductor are configured to realize switching control of a plurality of phases of power,
The electric working machine is characterized in that the electric drive device switches only one of a plurality of legs in the first and second leg groups. The electric working machine according to any one of claims 1 to 11, or any one of claims 14 to 18.
The third and fourth leg groups and the second inductor are configured to realize switching control of a plurality of phases of power,
The electric working device is configured to switch a plurality of legs in the third and fourth leg groups so that phases of the plurality of phases of electric power are shifted. The electric working machine according to any one of claims 1 to 11, or any one of claims 14 to 18.
The third and fourth leg groups and the second inductor are configured to realize switching control of a plurality of phases of power,
The electric working machine is characterized in that the electric drive device switches only one of a plurality of legs in the third and fourth leg groups.

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