JP2010200403A - Power unit and power conversion system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that in a conventional system, it is difficult to accurately control the voltage of a floating power source (a capacitor 28) of a drive circuit DC, when supplying energy of a power source 10 within a low-voltage system to a drive circuit DC for a power switching element which constitutes a high-voltage system insulated therefrom. <P>SOLUTION: The power switching element Sup is driven according to a drive signal (e.g., gup in the figure) that is transmitted via a photocoupler 32 by a drive control circuit 30. A primary side of the photocoupler 32 uses a capacitor 48 as a power source. A control circuit 38 controls supply of power to a transformer 20 in the drive circuit DC by a power-on operation signal for feedback controlling the voltage of the capacitor 48. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a power supply apparatus that supplies energy of a power supply in a first system to a drive circuit of a power switching element constituting a second system insulated from the power supply system, and a power conversion system including the power supply apparatus.

  For example, in an inverter connected to a motor generator as a main machine of a vehicle, there is a need to insulate a drive circuit of each switching element that constitutes the vehicle low-voltage system. For this reason, the low-voltage battery is connected to the primary coil of the transformer and the power supply (floating power supply) of the drive circuit is connected to the secondary coil, so that the energy of the low-voltage battery is supplied to the floating power supply via the transformer. It is well known.

  In this case, it is desirable to use the floating power supply voltage information to control the floating power supply voltage by energizing the primary coil. Therefore, conventionally, for example, as can be seen in Patent Document 1, it has been proposed to feed back a voltage related to one power source among floating power sources corresponding to each of the six switching elements constituting the inverter to the low-voltage system. Thereby, the energization operation on the primary side of the six transformers can be performed based on the floating power supply voltage information.

JP-A-11-178356

  However, in the above case, in order to acquire the floating power supply voltage information, it is necessary to add a means for insulating the low voltage system from the high voltage system. In addition, it is necessary to add a configuration for accurately transmitting floating power supply voltage information from the high voltage system to the low voltage system.

  SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to drive a power switching element that constitutes a second system that is insulated from the energy of the power source in the first system. To provide a power supply device capable of acquiring power supply voltage information of a drive circuit without adding a means for insulating the second system and the first system when supplying to the power supply system, and a power conversion system including the power supply device is there.

  Hereinafter, means for solving the above-described problems and the operation and effects thereof will be described.

  According to a first aspect of the present invention, there is provided a second system power storage means as a power source for a drive circuit of a power switching element constituting a second system insulated from the first system, and a primary power source for the first system. And a supply transformer having a secondary side connected to the second system power storage means, and a first system power storage having a primary side connected to the power source of the first system and in the first system An energization operation for energizing the supply transformer in response to an operation signal when energizing the monitoring transformer to feedback control the voltage of the first system power storage unit And a drive signal of the power switching element from the first system to the second while insulating between the first system and the second system. And a transmitting means for transmitting to the system, the power of the transmission means, characterized in that the first system storage means.

  Since the first system power storage means serves as a power source for the transmission means, the power is consumed as the power switching element is driven. On the other hand, every time the power switching element is driven, the power of the second system power storage means is consumed. For this reason, it is considered that there is a positive correlation between the amount of energy stored in the first system power storage means and the amount of energy stored in the second system power storage means. In the above invention, in view of this point, the voltage of the second system power storage means is controlled as desired by performing the power supply operation of the supply transformer by the power supply operation signal for feedback control of the voltage of the first system power storage means. be able to.

  According to a second aspect of the present invention, in the first aspect of the present invention, the power switching element includes a plurality of power switching elements, and at least one power source of transmission means corresponding to each of the plurality of power switching elements is supplied to the first power switching element. It is characterized by being a system power storage means.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the power switching element includes a plurality of power switching elements, and all of the power supplies of the transmission means corresponding to the plurality of power switching elements are stored in the first system power storage. It is characterized by making it a means.

  The above invention is particularly effective when the power switching element is an inverter that connects the positive and negative electrodes of the DC power source and the terminal of the rotating machine.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the power switching element includes at least one pair of power switching elements that are insulated from each other and driven in a complementary manner. Thus, the primary side of the insulating transformer is shared between power switching elements that are complementarily driven.

  In the above invention, by sharing the primary side of the insulating transformer between power switching elements that are complementarily driven, the number of transformers can be reduced as compared with a case where these are separated. Further, since the pair of power switching elements have the same on / off frequency, it is considered that the power consumption of the second system power storage means is also substantially equal. For this reason, each of the 2nd system power storage means can also be suitably charged by electric power supply through energization operation to a single primary side coil.

  The invention according to claim 5 is the invention according to any one of claims 1 to 3, wherein the power switching element constitutes a three-phase inverter, and the primary side of the insulating transformer is The three-phase inverter is shared for each upper arm and each lower arm.

  In the above invention, by sharing the primary side of the insulating transformer between the power switching elements for each upper arm and each lower arm, the number of transformers can be reduced compared to the case where these are separated. Can do. In addition, since the power switching elements of the upper arm and the lower arm have the same on / off frequency around one electrical angle cycle of the rotating machine, the power consumption of the second system power storage means around one electrical angle cycle. The amount is also considered to be approximately equal. For this reason, each of the 2nd system power storage means can also be suitably charged by electric power supply through energization operation to a single primary side coil.

  The invention according to claim 6 is the invention according to any one of claims 2 to 5, wherein the signal for performing the energization operation on the primary side of the plurality of monitoring transformers is generated by a single energization operation means. The common signal is a common signal.

  In the said invention, it can be set as a simple structure as much as possible by making the signal which performs electricity supply operation common.

  The invention according to claim 7 is the invention according to any one of claims 1 to 6, wherein the power switching element constitutes a power conversion circuit in the in-vehicle high voltage system insulated from the in-vehicle low voltage system. It is characterized by being.

  The invention according to claim 8 is a power conversion system comprising the power supply device according to claim 7 and the power conversion circuit.

  In the said invention, the system which suppressed the increase in the number of insulation means suitably is implement | achieved by providing the power supply device of Claim 7.

1 is a system configuration diagram according to a first embodiment. FIG. The system block diagram concerning 2nd Embodiment. The side view which shows the structure of the transformer concerning the embodiment. The system block diagram concerning 3rd Embodiment.

(First embodiment)
Hereinafter, a first embodiment in which a power supply apparatus according to the present invention is applied to a power supply apparatus for a hybrid vehicle will be described with reference to the drawings.

  FIG. 1 shows a system configuration according to the present embodiment.

  The drive circuit DC is a drive circuit for a power switching element that constitutes an in-vehicle inverter. Here, the inverter is a power conversion circuit connected to a three-phase rotating machine as an in-vehicle main machine. In the figure, the power switching elements Sup and Sun for connecting the U-phase terminal of the three-phase rotating machine to the positive and negative electrodes of a DC power supply (not shown) and the V-phase terminal to the positive and negative electrodes of the DC power supply, respectively. Power switching elements Svp and Svn that connect the W-phase terminal to the positive electrode and the negative electrode of the DC power supply, respectively, are shown. The inverter and the three-phase rotating machine constitute an in-vehicle high-voltage system that is insulated from the in-vehicle low-voltage system. Hereinafter, the six power switching elements constituting the inverter are collectively referred to as a power switching element S.

  The drive circuit DC uses the power supply 10 as an energy supply source. The power source 10 is a power source provided in the in-vehicle low voltage system. The power source 10 may be a low-voltage battery (with an output voltage of about “12 V”, for example) for in-vehicle auxiliary equipment, or a stabilized power source that steps down and stabilizes the output voltage of the low-voltage battery. Good.

  Energy transmission from the power supply 10 to the drive circuit DC is performed in a state where the in-vehicle low voltage system and the in-vehicle high voltage system are insulated. In order to realize this, each drive circuit DC includes a transformer 20. Here, the primary side coil 20a of the transformer 20 constitutes an in-vehicle low voltage system, and the secondary side coil 20b of the transformer 20 constitutes an in-vehicle high voltage system. One terminal (here, the winding start side is illustrated) of the primary side coil 20 a of the transformer 20 is connected to the power supply 10, and the other terminal is grounded via the switching element 24. One terminal of the primary side coil 20 a of the transformer 20 and the ground are connected by a capacitor 22. The capacitor 22 serves as a power source for energizing the primary coil 20a. That is, in the case where the drive circuit DC (primary coil 20a) is separated from the power supply 10 and the power supply 10 is used as a direct power supply, the influence of noise or the like may be significant. 22 is a direct power source. The switching element 24 is an opening / closing means for opening / closing a loop circuit including the capacitor 22 and the primary side coil 20a, and is used for performing an energization operation of the primary side coil 20a.

  Capacitors 28 are connected to both ends of the secondary coil 20b of the transformer 20. Specifically, one terminal (here, the winding end side is illustrated) of the secondary coil 20 b is connected to one electrode of the capacitor 28 via the diode 26. Here, the diode 26 is a rectifying means for fixing the charging polarity of the capacitor 28. The capacitor 28 serves as a power source (floating power source) on the in-vehicle high voltage system side (secondary coil 20b side) of the drive circuit DC. In particular, the capacitor 28 serves as a power source for the drive control circuit 30.

  The drive control circuit 30 applies the voltage of the capacitor 28 to the conduction control terminal (gate) of the power switching element S, thereby charging the gate of the capacitor 28 and connecting the gate to the output terminal (emitter). Thus, a process of discharging the charge charged in the gate is performed. These processes, that is, the process of turning on / off the power switching element S are performed based on a drive signal output from a control device (not shown) in the in-vehicle low-pressure system. Incidentally, in the figure, only the drive signal gup of the power switching element Sup is shown, but in the following, when the drive signals of the six power switching elements are collectively described, the drive signal g is used.

  When transmitting the drive signal g, the photocoupler 32 is used to insulate the in-vehicle low voltage system and the in-vehicle high voltage system. The primary side (photodiode side) of the photocoupler 32 uses a capacitor 48 as a power source. Capacitor 48 receives energy in a circuit similar to that used by capacitor 28 in the high voltage system to receive power supply 10 energy.

  That is, this circuit includes a transformer 40. The power supply 10 is connected to one terminal of the primary side coil 40 a of the transformer 40, and the other terminal is grounded via the switching element 44. Further, one terminal of the primary side coil 40 a of the transformer 40 and the ground are connected by a capacitor 42. The capacitor 48 is connected to both ends of the secondary coil 40b of the transformer 40. Specifically, one terminal of the capacitor 48 is connected to one terminal of the secondary coil 40 b via the diode 46. The transformer 40, the switching element 44, the capacitor 42, and the diode 46 correspond to the transformer 20, the switching element 24, the capacitor 22, and the diode 26. Further, the polarity settings of the primary side coil 40a and the secondary side coil 40b of the transformer 40 are the same as the polarity settings of the primary side coil 20a and the secondary side coil 20b of the transformer 20.

  By the opening / closing operation of the switching element 44, the energy of the power source 10 is stored in the capacitor 48 via the transformer 40. The capacitor 48 is connected to the anode of the photodiode of the photocoupler 32, and the cathode of the photodiode is grounded via the switching element 34. The switching element 34 is a switch that is opened and closed according to the logical value of the drive signal g. When the switching element 34 is closed, a current flows from the capacitor 48 to the ground via the photodiode and the switching element 34. As a result, the phototransistor of the photocoupler 32 is turned on. The phototransistor uses the capacitor 28 as a power supply, and outputs a logic signal corresponding to the drive signal g to the drive control circuit 30. Thereby, in the drive control circuit 30, the power switching element S is driven according to the command of the drive signal g.

  Next, a voltage control method for the capacitor 28 will be described.

  The voltage of the capacitor 28 is controlled by the on / off operation of the switching element 24. That is, it is controlled by the on / off operation of the switching element 24 in the low voltage system insulated from the capacitor 28. The switching element 24 is controlled by the control circuit 38. The control circuit 38 operates the switching element 44 so as to control the voltage of the capacitor 48 as desired, and simultaneously operates the switching element 24 of each drive circuit DC by the operation signal of the switching element 44.

  Here, the electric charge of the capacitor 48 is consumed every time the drive signal g of any of the six power switching elements S becomes a logical value for closing the switching element 34. On the other hand, the gate of the power switching element S is charged each time the drive signal g becomes a logical value for commanding the on operation, so that the charge of the capacitor 28 is consumed. In this way, by using the capacitor 48 as the primary power source of the photocoupler 32, a positive correlation can be established between the charge of the capacitor 28 and the charge of the capacitor 48. A positive correlation can be established with the voltage of the capacitor 48. In particular, the charge consumption of the capacitor 48 has a correlation with the average value of the charge consumption of the capacitors 28 of all the drive circuits DC. Therefore, by controlling the voltage of the capacitor 48, the voltage of each capacitor 28 of all the drive circuits DC can be suitably controlled.

  Incidentally, the capacitance of the capacitor 48 and the capacitance of the capacitor 22 are appropriately adapted so that the voltage control of each capacitor 28 of the drive circuit DC can be satisfactorily controlled according to the operation amount of the voltage control of the capacitor 48. It is desirable.

  According to the embodiment described in detail above, the following effects can be obtained.

  (1) When the power source on the primary side of the photocoupler 32 for transmitting the operation signal of the power switching element S from the low voltage system to the high voltage system is the capacitor 48 and the transformer 40 is energized for feedback control of the voltage of the capacitor 48, The transformer 20 was energized by this energization operation signal. Thereby, the voltage of the capacitor 28 can be controlled as desired without transmitting the voltage information of the capacitor 28 from the high voltage system to the low voltage system.

  (2) All the primary power sources of the photocouplers 32 corresponding to the power switching elements S constituting the inverter IV are the capacitors 48. Thereby, the power consumption of the capacitor 48 can be made to correspond to the total power consumption of the capacitor 28 corresponding to the power switching element S.

  (3) The signal for performing the energization operation on the primary side of each transformer 20 of the drive circuit DC is a single signal generated by the single control circuit 38. Thereby, a power supply device can be set as simple as possible.

(Second Embodiment)
Hereinafter, the second embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  FIG. 2 shows a system configuration diagram according to the present embodiment. 2, members corresponding to those shown in FIG. 1 are given the same reference numerals for the sake of convenience.

  As shown in the figure, the present embodiment includes a drive circuit DC for each phase. In other words, the drive circuit is shared by the upper arm and the lower arm that are driven complementarily to each other (in the figure, the U-phase drive signals gup and gun are complementary signals) is doing). That is, the drive circuit DC is provided for each of the power switching elements Sup, Sun, the power switching elements Svp, Svn, and the power switching elements Swp, Swn.

  Here, the drive circuit DC basically includes the same circuit as the circuit shown in FIG. 1 for each of the upper arm and the lower arm. However, the upper side and the lower arm share the primary side of the transformer 20. That is, the drive circuit DC includes a single transformer 20. Here, the transformer 20 includes a pair of secondary coils 20b and 20c sharing a magnetic path with the primary coil 20a.

FIG. 3 schematically shows the structure of the transformer 20 according to the present embodiment. As shown in the figure, the transformer 20 is configured such that a closed magnetic circuit generated when a current flows through the primary coil 20a is linked by a pair of secondary coils 20b and 20c. Incidentally, FIG. 3 shows an iron core CF for forming a closed magnetic circuit, a primary coil 20a, a pair of secondary coils 20b. 20c is illustrated and the iron core CF is provided with a gap, but the iron core CF itself may be a closed loop. According to the embodiment described in detail above, In addition to the effects according to the above effects of the embodiment, the following effects can be obtained.

  (4) The primary side of the transformer 20 is shared between power switching elements that are complementarily driven. Thereby, the number of transformers can be reduced as compared with the case where the primary side is different. Further, since the power switching elements S of the upper and lower arms have the same on / off frequency, it is considered that the power consumption is substantially equal between the capacitors 28 corresponding to the upper and lower arms. For this reason, a pair of capacitor | condenser 28 can also be charged suitably by the electric power supply through the electricity supply operation to the single primary side coil 20a. Further, since the closed magnetic circuit where the secondary coils 20b and 20c that output current to each capacitor 28 are linked is common, the voltage between the capacitor 28 corresponding to the upper arm and the capacitor 28 corresponding to the lower arm is sufficiently high. Can also be approximated.

(Third embodiment)
Hereinafter, the third embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  FIG. 4 shows a system configuration diagram according to the present embodiment. In FIG. 4, members corresponding to those shown in FIG. 1 are given the same reference numerals for the sake of convenience.

  In the present embodiment, a drive circuit DC is provided for each arm. That is, the drive circuit DC is shared by the power switching elements Sup, Svp, Swp in the upper arm and the power switching elements Sun, Svn, Swn in the lower arm.

  Here, the drive circuit DC basically includes the same circuit as the circuit shown in FIG. 1 for each phase. However, the primary side of the transformer 20 is shared between these phases. That is, the drive circuit DC includes a single transformer 20. Here, the transformer 20 includes secondary coils 20b, 20c, and 20d that share a magnetic path with the primary coil 20a, and these correspond to the U-phase, V-phase, and W-phase, respectively. ing. Note that the structure of the transformer 20 is obtained by increasing the number of secondary coils by one in the structure shown in FIG.

  According to the embodiment described above in detail, the following effects can be obtained in addition to the effects according to the above-described effects of the first embodiment.

  (5) The primary side of the transformer 20 is shared for each upper arm and lower arm of the three-phase inverter. Thereby, the number of transformers can be reduced as compared with the case where a primary coil is provided for each phase of each arm. In addition, since the power switching elements of the upper arm and the lower arm have the same frequency of on / off around one electrical angular period of the rotating machine, the power consumption of the capacitor 28 per one electrical angular period is also approximately. It is considered equal. For this reason, the capacitor | condenser 28 of each phase can also be suitably charged by the electric power supply through the electricity supply operation to the single primary side coil 20a. Furthermore, since the closed magnetic circuit where the secondary coils 20b, 20c, and 20d that output currents to the capacitors 28 are linked is common, the voltages of the capacitors 28 corresponding to the respective phases can be sufficiently approximated.

(Other embodiments)
Each of the above embodiments may be modified as follows.

  In the first embodiment, the drive circuit DC of each power switching element Sun, Svn, Swn of the lower arm may be changed to the drive circuit DC of the third embodiment.

  In the first and second embodiments, the primary power sources of the photocouplers 32 (6 in total) in the drive circuit DC are all capacitors 48, but the present invention is not limited to this. For example, only the primary power supply of the photocoupler 32 corresponding to the U-phase power switching elements Sup and Sun may be used as the capacitor 48, and the power supply 10 may be used as the power supply for the remaining photocouplers 32. Further, for example, only one primary side power supply of the six photocouplers 32 may be used as the capacitor 48, and the power supply 10 may be used as the power supply for the remaining photocouplers 32.

  In the third embodiment, the primary power source of the photocoupler 32 in the drive circuit DC is all the capacitor 48, but the present invention is not limited to this. For example, only the primary power supply of the photocoupler 32 corresponding to the upper arm may be used as the capacitor 48, and the power supply 10 may be used as the power supply for the remaining photocouplers 32. Further, for example, only one primary side power supply of the six photocouplers 32 may be used as the capacitor 48, and the power supply 10 may be used as the power supply for the remaining photocouplers 32. Further, for example, only the primary side power source of the photocoupler 32 corresponding to the U-phase power switching elements Sup and Sun may be used as the capacitor 48, and the power source 10 may be used as the power source for the remaining photocouplers 32.

  In each of the above embodiments, the capacitors 22 are connected to both ends of the primary side coil 20a of all the transformers 20, but the present invention is not limited to this. For example, in the case where the distance between each transformer 20 and the power supply 10 varies greatly, the capacitor 22 may be connected only to a long distance.

  In each of the above embodiments, the operation signal of the switching element 24 for performing the energization operation of the transformer 20 in each drive circuit DC is generated by the single control circuit 38, but is not limited thereto. For example, the control circuit 38 may be provided separately for each drive circuit DC. In this case, when each power switching element is provided with a separate drive circuit DC as in the first embodiment, the voltage of the capacitor 48 changes only by the drive signal of each corresponding power switching element. The voltage of 28 can be controlled more suitably.

  In the first embodiment, the polarities of the secondary side coils 20b of the transformer 20 are the same, but the present invention is not limited to this. For example, in the first embodiment, the relationship is reversed between the upper arm and the lower arm of each phase, and the polarity of the secondary coil 20b of each phase is the secondary coil 40b of the transformer 40. Only the primary side power supply of the photocoupler on the side corresponding to the same polarity as the capacitor may be used as the capacitor 48. Even in this case, it is considered that the voltage of each capacitor 28 can be controlled particularly suitably if the pair of power switching elements driven by the drive circuit DC are driven in a complementary manner. Furthermore, also in the second and third embodiments, the polarities of the secondary coils of the transformer 20 in the drive circuit DC need not be the same. In other words, the connection relationship between the winding start and winding end of the plurality of secondary coils in the drive circuit DC and the other circuits (diode 26, capacitor 28, and drive control circuit 30) is not limited to the same. Absent.

  The transmission means for transmitting the drive signal of the power switching element from the low voltage system to the high voltage system while insulating between the high voltage system and the low voltage system is not limited to the photocoupler 32 but may be any photo-insulating element such as a photo MOS relay. May be. Moreover, it is not limited to an optical insulating element, and may be a magnetic insulating element, for example.

  The power conversion circuit is not limited to an inverter, and may be, for example, a step-down converter that steps down the voltage of the on-vehicle high-voltage battery and outputs it to the on-vehicle low-voltage battery. At this time, the present invention is not limited to the one including a series connection body of a pair of power switching elements on the high potential side and the low potential side. Further, even in the inverter, the pair of power switching elements is not limited to being driven complementarily.

  In each of the above embodiments, the present invention is applied when the power of the power source 10 of the low voltage system is output to the high voltage system. However, the present invention is not limited to this, and the present invention is applied when the power of the high voltage system power source is output to the low voltage system. You may apply.

  In each of the above embodiments, the present invention is applied to a hybrid vehicle. However, the present invention is not limited to this. For example, the present invention may be applied to an electric vehicle or a fuel cell vehicle.

  DESCRIPTION OF SYMBOLS 10 ... Power supply, 20 ... Transformer (one embodiment of supply transformer), 20a ... Primary coil, 20b ... Secondary coil, 38 ... Control circuit (one embodiment of energizing operation means), 40 ... Transformer (monitoring) Embodiment of transformer for use).

Claims (8)

A second system power storage means as a power source for the drive circuit of the power switching element constituting the second system insulated from the first system;
A supply transformer having a primary side connected to the power source of the first system and a secondary side connected to the second system power storage means;
A monitoring transformer having a primary side connected to the power source of the first system and a secondary side connected to a first system power storage means in the first system;
Energization operation means for energizing the supply transformer according to an operation signal when energizing the monitoring transformer to feedback control the voltage of the first system power storage means;
Transmission means for transmitting a drive signal of the power switching element from the first system to the second system while insulating between the first system and the second system;
A power supply apparatus characterized in that a power source of the transmission means is the first system power storage means. The power switching element comprises a plurality of
2. The power supply apparatus according to claim 1, wherein at least one power source among transmission means corresponding to each of the plurality of power switching elements is the first system power storage means. The power switching element comprises a plurality of
The power supply apparatus according to claim 1 or 2, wherein all of the power supplies of the transmission means corresponding to each of the plurality of power switching elements are the first system power storage means. The power switching element comprises one or more pairs of power switching elements that are insulated from each other and driven in a complementary manner,
4. The power supply device according to claim 1, wherein a primary side of the insulating transformer is shared between power switching elements that are complementarily driven. 5. The power switching element constitutes a three-phase inverter,
4. The power supply device according to claim 1, wherein the primary side of the insulating transformer is shared for each of the upper arm and the lower arm of the three-phase inverter.   The signal for performing the energization operation on the primary side of the plurality of monitoring transformers is a common signal generated by a single energization operation means. Power supply.   The power supply device according to any one of claims 1 to 6, wherein the power switching element constitutes a power conversion circuit in an in-vehicle high-voltage system insulated from the in-vehicle low-voltage system. The power supply device according to claim 7,
A power conversion system comprising the power conversion circuit.

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