JP2016077104A - Power conversion device and work machine employing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power conversion device capable of performing stable control.SOLUTION: M pieces (M≥2) of reactors L1, L2, ... which are available for the power conversion device and of which the inductance is equal are provided. M pieces of lead wires 134 are wound around (p) pieces (2≤p≤N) of cores among N pieces (N≥M) of cores and form (p) pieces of coils which are electrically connected in series. Q pieces (2≤q) of coils which are wound around the same core 132 have the substantially equal winding number and generate magnetic fluxes in the same direction.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a power conversion device.

  In recent construction machines such as power shovels and cranes, a hybrid type of a hydraulic motor and an AC motor is used as a power source for the upper swing body. The hybrid-type turning power source assists the hydraulic motor with an AC motor during acceleration of the upper turning body, performs a regenerative operation with the AC motor during deceleration, and charges a storage battery such as a battery with generated energy.

  A power converter using a bidirectional DC / DC converter (also referred to as a step-up / down converter) is used to exchange energy between an AC motor and a storage battery such as a battery or a capacitor. FIG. 1 is a circuit diagram showing a basic configuration of bidirectional DC / DC converter 110.

  The battery 102 is connected to the primary side of the bidirectional DC / DC converter 110, and the DC bus 104 is connected to the secondary side thereof. The DC bus 104 is connected to the inverter 18. For the bidirectional DC / DC converter 110, the inverter 18 functions as a variable current source that generates a variable load current Im. For example, when the AC motor performs a power running operation, the load current Im is positive, and when the regenerative operation is performed, the load current Im is negative.

  A large current of several tens of A to several hundreds of A flows through the reactor (inductor) of the bidirectional DC / DC converter 110, but a reactor having a large current capacity is very expensive. Therefore, as shown in FIG. 1, a parallel structure in which a plurality of reactors L1 and L2 are connected in parallel is used. Bidirectional DC / DC converter 110 includes smoothing capacitor C1 and transistors M1 and M2 in addition to reactors L1 and L2. Since the topology of the bidirectional DC / DC converter 110 is known, the description thereof is omitted.

The controller 120 receives a voltage command Vr indicating a target value of the voltage (DC link voltage) _VDC of the DC bus 104 from an upstream controller. The controller 120 also receives a current detection value indicating the total current (converter current) of the reactors L1 and L2 from the current sensor CT. The controller 120 controls the switching duty ratio of the transistors M1 and M2 so that the DC link voltage V _DC coincides with the voltage command Vr, and adjusts the converter current flowing through the reactors L1 and L2.

JP 2010-148288 A JP 2009-266978 A

  FIG. 2 is a diagram illustrating a configuration of a plurality of reactors. The first reactor L1 includes a core 132_1 and a coil W1 wound around the core 132_1. Similarly, the second reactor L2 includes a core 132_2 and a coil W2 wound around the core 132_2.

  FIG. 3 is a diagram illustrating the DC superimposition characteristics of the reactor. When the direct current flowing through the reactor exceeds a certain value, magnetic saturation occurs, and the inductance decreases as the direct current increases. This is called DC superposition characteristics. In the bidirectional DC / DC converter 110 having the parallel structure shown in FIG. 1, ideally, equal currents flow through the reactors L1 and L2. However, when the current balance is lost and the current concentrates on one reactor L1, the inductance (that is, impedance) of the one reactor L1 on which the current is concentrated decreases, and the current further concentrates, resulting in further inductance reduction. As described above, in the bidirectional DC / DC converter 110 of FIG. 1, current imbalance occurs and phenomena such as oscillation occur.

  In order to avoid this problem, the configuration of FIG. 4 is adopted. The bidirectional DC / DC converter 110 of FIG. 4 includes current sensors CT1 and CT2 provided for each of the reactors L1 and L2. The controller 120 individually controls the currents of the reactors L1 and L2 according to the detection values of the two current sensors CT1 and CT2.

  The bidirectional DC / DC converter 110 of FIG. 4 can suppress current imbalance and oscillation of the plurality of reactors L1 and L2, but requires two current sensors CT and complicates the control system. Therefore, the circuit cost increases. Such a problem may occur not only in the bidirectional DC / DC converter 110 but also in various power converters using a reactor such as a boost converter and a step-down converter.

  The present invention has been made in view of such a problem, and one of the exemplary purposes of an aspect thereof is to provide a power conversion device capable of stable control.

  One embodiment of the present invention relates to a power converter. The power conversion apparatus includes a DC bus, a switching circuit connected to the DC bus, and a plurality of M (M ≧ 2) reactors that are connected to the switching circuit to form a parallel current path and have substantially the same inductance. And comprising. The M reactors include a plurality of N (N ≧ M) cores and M conductive wires. Each of the M conductors is wound around a plurality of N cores of N cores (2 ≦ p ≦ N) to form p coils electrically in series. A plurality of q (2 ≦ q) coils wound around the same core have substantially the same number of turns and generate magnetic flux in the same direction.

  In this aspect, when magnetic saturation occurs in any of the cores, the inductances of the plurality of coils wound around the core are substantially reduced. By sharing each other in this way, it is possible to suppress unbalance and oscillation of currents flowing through a plurality of reactors, and it is possible to stably control the power conversion device at low cost.

M * p = N * q may be sufficient.
In this case, a plurality of cores can be effectively used without leaving them.

M = q may be sufficient.
In this case, each of the plurality of M conductors can be divided into all N cores and wound, and when magnetic saturation occurs in one core, the inductances of all the reactors are equal (p− 1) / p times and good current balance can be maintained.

  q = 2 may be sufficient. In this case, it becomes easy to manufacture a plurality of reactors from the viewpoint of managing the number of turns of the coil.

  The plurality of cores may be annular cores. In this case, leakage magnetic flux can be reduced and high inductance can be obtained.

  Another aspect of the present invention relates to a work machine. The work machine includes an electric motor, an inverter that drives the electric motor, a power storage device, and the power conversion device according to any one of the above that transfers power to and from the power storage device and the inverter.

  Note that any combination of the above-described constituent elements and the constituent elements and expressions of the present invention replaced with each other among methods, apparatuses, systems, and the like are also effective as an aspect of the present invention.

  According to the present invention, it is possible to perform stable control while suppressing circuit cost.

It is a circuit diagram which shows the basic composition of a bidirectional DC / DC converter. It is a figure which shows the structure of a some reactor. It is a figure which shows the direct current | flow superimposition characteristic of a reactor. It is a circuit diagram which shows another structure of a bidirectional | two-way DC / DC converter. 1 is a circuit diagram of a bidirectional DC / DC converter according to an embodiment. It is a figure which shows the structure of the reactor unit which concerns on embodiment. It is an equivalent circuit schematic of the reactor unit of FIG. It is a figure which shows the structure of the reactor unit which concerns on a 1st modification. It is a figure which shows the structure of the reactor unit which concerns on a 2nd modification. It is a figure which shows the structure of the reactor unit which concerns on a 3rd modification. It is a figure which shows the structure of the reactor unit which concerns on a 4th modification. FIGS. 12A and 12B are views showing a reactor unit according to a fifth modification. It is a perspective view which shows the external appearance of the shovel which is an example of the construction machine which concerns on embodiment. It is a block diagram, such as an electric system and a hydraulic system, of the excavator according to the embodiment. It is a perspective view which shows the layout of a bidirectional DC / DC converter.

  The present invention will be described below based on preferred embodiments with reference to the drawings. The same or equivalent components, members, and processes shown in the drawings are denoted by the same reference numerals, and repeated descriptions are omitted as appropriate. The embodiments do not limit the invention but are exemplifications, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

  FIG. 5 is a circuit diagram of a bidirectional DC / DC converter (hereinafter also simply referred to as a converter) 110 according to the embodiment. The DC / DC converter 110 includes a DC bus 104, a smoothing capacitor C1, a switching circuit 112, a plurality of M (M ≧ 2) reactors L1 to LM (collectively referred to as a reactor unit 130), a current sensor CT, . The switching circuit 112 includes a high side transistor M1 and a low side transistor M2. For example, the switching circuit 112 may be configured by an IPM (Intelligent Power Module) or may be configured by a discrete component.

The plurality of M reactors L1 to LM are connected to the switching circuit 112 and form parallel current paths. The plurality of M reactors L1 to LM have substantially the same inductance. Current sensor CT detects a current flowing through converter 110, that is, a total current flowing through a plurality of reactors L1 to LM. Converter controller 120 controls switching circuit 112 so that voltage V _DC of DC bus 104 matches target value Vr.

  FIG. 6 is a diagram showing a configuration of the reactor unit 130 according to the embodiment. The M reactors L1 to LM include a plurality of N (N ≧ M) cores 132_1 to 132_N and M conductors 134_1 to 134_M. In addition, each conducting wire 134 does not need to be one physically continuous conducting wire, and a single conducting wire 134 may be formed by connecting a plurality of conducting wire portions in series. FIG. 6 shows a configuration with M = 2 and N = 2. The plurality of cores 132_1 to 132_M are preferably annular cores from the viewpoint of reducing leakage magnetic flux, but may be rod-shaped cores or other shapes as described later.

  Each of the M conductive wires 134_1 to 134_M is wound around a plurality of p cores (2 ≦ p ≦ N) out of the N cores 132_1 to 132_N to form p coils electrically in series. Specifically, the i-th (1 ≦ i ≦ M) conductor 134_i is wound around p cores 132_1 to 132_p, and includes p coils Wi_1 to Wi_P electrically in series.

The plurality of coils wound around the same core 132 — j (1 ≦ j ≦ N) have substantially the same number of turns n _j and are wound so as to generate magnetic flux in the same direction.

  A plurality of Q wires (2 ≦ Q ≦ N) are equally wound around each of the plurality of cores 132_1 to 132_M, and p = N × q / M. That is, it is desirable that the cores 132_1 to 132_M have the same shape and the same size. In FIG. 6, q = 2 and p = 2.

  The first conducting wire 134_1 corresponds to the reactor L1 in FIG. 5, and the second conducting wire 134_2 corresponds to the reactor L2 in FIG. One end (first port) P1_i of each conducting wire 134_i corresponds to one end of the reactor Li, and the other end P2_i corresponds to the other end of the reactor Li. In use, the first ports P1_1 to P1_M of the plurality of conductors 134_1 to 134_M are electrically connected in common, and the second ports P2_1 to P2_M of the plurality of conductors 134_1 to 134_M are also electrically connected in common, and A current path in which the reactors L1 to LM are parallel to each other is formed.

  The above is the configuration of the reactor unit 130. Next, the principle will be described. FIG. 7 is an equivalent circuit diagram of the reactor unit 130 of FIG. The conducting wire 134_1 includes coils W1_1 and W1_2 connected in series, and the conducting wire 134_2 includes coils W2_1 and W2_2 connected in series. The inductance of the coil Wi_j is denoted as Li_j, and the direct current resistance is denoted as Ri_j.

A plurality of cores 132 respectively (core 132_J), it because all coils W1_j to be wound, the winding number _{n j} of W2_j equal inductance L1_j, L2_j is represented equally _{L j,} also the coil W1_j, resistance W2_j value R1_j, R2_j also represented equally _{R j. n 1} = n 2 = ... = a _{n N, L 1 = L 2} = ... = L N, R 1 = R 2 = ... = may be _{R N.}

The current through the voltage across the reactor units 130 V, in conductor 134_1 referred to as _{I 1.} At this time, the following formula (1) is established in the conducting wire 134_1 of the reactor unit 130 of FIG.
V = Σ _{j = 1: N} (L _j · dI ₁ / dt + R _j · I ₁ ) (1)
Of course, the same formula (2) holds for the conductor 134_2.
V = Σ _{j = 1: N} (L _j · dI ₂ / dt + R _j · I ₂ ) (2)

Now, the permeability μ is decreased magnetic saturation occurs in one core 132_1, it coils W1_1 being wound, the inductance L1_1 = L2_1 = _{L 1} of W1_2 drops to equal zero.
In this case, Equation (3) is obtained for the first conductor 134_1.
V = L ₂ · dI ₁ / dt + (R ₁ + R ₂ ) · I ₁
= {L ₂ · d / dt + R ₁ + R ₂ } · I ₁ (3)
Therefore, the current I _{1 of the} conducting wire 134_1 is given by equation (4).
I ₁ = V / {L ₂ · d / dt + R ₁ + R ₂ } (4)

In this case, the expression (5) is obtained for the second conductor 134_2.
V = L ₂ · dI ₂ / dt + (R ₁ + R ₂ ) · I ₂
= {L ₂ · d / dt + R ₁ + R ₂ } · I ₂ (5)
Accordingly, the current _{I 2} of the conductor 134_2 is given by equation (6).
I ₂ = V / {L ₂ · d / dt + R ₁ + R ₂ } (6)
Comparing equations (4) and (6), I ₁ = I ₂ is obtained.

  The effect of the reactor unit 130 according to the embodiment will be further clarified by comparison with the reactor of FIG. In the configuration of FIG. 2, when magnetic saturation occurs in one core 132_1, only the inductance of one reactor L1 is reduced, and the inductance of the other reactor L2 is maintained. As a result, current concentration on the reactor L1 is promoted, causing further reduction in inductance.

On the other hand, according to the reactor unit 130 according to the embodiment, even if magnetic saturation occurs in any of the cores as derived from the equations (4) and (6), a plurality of conducting wires (coils) 134 are used. Currents I ₁ and I ₂ can be kept substantially equal.

  Moreover, according to the reactor unit 130 according to the embodiment, when magnetic saturation occurs, current concentration on a certain conductor (reactor) is less likely to occur, and therefore further reduction in inductance of the conductor can be suppressed.

  By using the reactor unit 130 for the bidirectional DC / DC converter 110, it is difficult for oscillation to occur, and the stability of the system can be improved. Alternatively, the feedback loop algorithm for stabilizing the system can be simplified, and maintenance can be facilitated. Alternatively, even if current concentration occurs in any of the reactors, the time until the oscillation can be delayed as compared with the conventional system. Therefore, by switching the control so as to suppress the oscillation in the meantime, Can improve the stability.

  According to a person skilled in the art, there are various combinations of the number of parallel reactors (number of conductors) M, the number of cores N, the number of coils per reactor (conductor) (number of divisions) p, and the number of coils q per core. It will be appreciated that various modifications may exist.

(First modification)
FIG. 8 is a diagram showing a configuration of a reactor unit 130a according to the first modification. In this modification, the number of parallel reactors (number of conductors) M = 2, the number of cores N = 3, the number of coils per conductor (number of divisions) p = 3, and the number of coils q per core q = 3.

  When N cores are used, when magnetic saturation occurs in one core, the inductance of each of the plurality of reactors L1 and L2 is (N-1) / N times. Therefore, by increasing N to 3, 4,..., The influence when magnetic saturation occurs can be reduced.

(Second modification)
FIG. 9 is a diagram illustrating a configuration of a reactor unit 130b according to the second modification. In this modification, the number of reactors in parallel (number of conductors) M = 3, the number of cores N = 3, the coil p = 3 per conductor, and the number of coils q = 3 per core.

  In this modification, the number M of parallel reactors is 3, and a larger current can flow than in the case where M = 2.

(Third Modification)
FIG. 10 is a diagram illustrating a configuration of a reactor unit 130c according to the third modification. In this modification, the number of reactors in parallel (number of conductors) M = 3, the number of cores N = 3, the number of coils per conductor p = 2, and the number of coils per core q = 2.

  In this modification, when magnetic saturation occurs in the core 132_1 and the coils W1_1 and W2_1 become zero, the inductance of the reactors L1 and L2 is halved, and the inductance of the reactor L3 is maintained as it is. Is done. Therefore, from the viewpoint of maintaining the current balance, the current balance is inferior to that of the embodiment and the first and second modifications, but an improved current balance can be realized as compared with the conventional reactor of FIG.

  In other words, in order to increase the current balance, the number of reactors in parallel (number of conductors) M and the number of coils per core q may be made equal as in the first embodiment and the first and second modifications. . In this case, all the reactors are configured by p (= M × q / N) coils connected in series, and when magnetic saturation occurs in one core, the inductances of the M reactors Is (p-1) / p times, and a high current balance can be maintained.

(Fourth modification)
FIG. 11 is a diagram illustrating a configuration of a reactor unit 130d according to a fourth modification. In this modification, the number of reactors in parallel (number of conductors) M = 4, the number of cores N = 4, the number of coils per conductor p = 2, and the number of coils per core q = 2.

  It will be understood by those skilled in the art that other combinations of M, N, p, and q may exist in addition to the first to fourth modifications, and that other modifications are also included in the scope of the present invention. The

(5th modification)
In the embodiment, the case where the annular core is used has been described, but the present invention is not limited thereto. FIGS. 12A and 12B are views showing reactor units 130e and 130f according to the fifth modification. The reactor unit 130e in FIG. 12A has M = 2, N = 2, p = 2, and q = 2, and a rod-shaped core 132 is used. In the modified example of FIG. 12A, the inductance is reduced due to the influence of the leakage magnetic flux at the end of the core 132. Therefore, the characteristics are inferior to those in the case of using the annular core, but the length of the core 132 is increased. Thus, it is easy to increase the number of coils q per core.

  The reactor unit 130f in FIG. 12B has M = 2, N = 3, p = 3, and q = 2. In this modification, annular magnetic bodies 136 and 138 are coupled to end portions of the M rod-shaped cores 132_1 to 132_3 so as to form a magnetic path for reducing leakage magnetic flux. In the case of using an annular core, when the number M of cores 132 is increased, the layout of the cores and conductors becomes complicated. According to the modification of FIG. 12B, the number M of cores 132 can be easily increased without complicating the layout.

  Next, the application of the bidirectional DC / DC converter 110 according to the embodiment will be described. FIG. 13 is a perspective view illustrating an appearance of an excavator 1 that is an example of the construction machine according to the embodiment. The excavator 1 mainly includes a traveling mechanism 2 and an upper revolving body (hereinafter also simply referred to as a revolving body) 4 that is rotatably mounted on the upper portion of the traveling mechanism 2 via a revolving mechanism 3.

  The revolving body 4 is attached with a boom 5, an arm 6 linked to the tip of the boom 5, and a bucket 10 linked to the tip of the arm 6. The bucket 10 is a facility for capturing suspended loads such as earth and sand and steel materials. The boom 5, the arm 6, and the bucket 10 are hydraulically driven by a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9, respectively. Further, the revolving body 4 is provided with a power source such as a driver's cab 4a for accommodating an operator who operates the position of the bucket 10, excitation operation and release operation, and an engine 11 for generating hydraulic pressure. The engine 11 is composed of, for example, a diesel engine.

  FIG. 14 is a block diagram of an electric system and a hydraulic system of the excavator 1 according to the embodiment. In FIG. 14, the mechanical power transmission system is indicated by a double line, the hydraulic system is indicated by a thick solid line, the steering system is indicated by a broken line, and the electrical system is indicated by a thin solid line.

  The excavator 1 includes a motor generator 12 and a speed reducer 13, and the rotation shafts of the engine 11 and the motor generator 12 are connected to each other by being connected to the input shaft of the speed reducer 13. When the load of the engine 11 is large, the motor generator 12 assists (assists) the driving force of the engine 11 with its own driving force, and the driving force of the motor generator 12 passes through the output shaft of the speed reducer 13 to the main pump 14. Communicated. On the other hand, when the load on the engine 11 is small, the driving force of the engine 11 is transmitted to the motor generator 12 via the speed reducer 13, so that the motor generator 12 generates power. The motor generator 12 is configured by, for example, an IPM (Interior Permanent Magnetic) motor in which a magnet is embedded in the rotor. Switching between driving of the motor generator 12 and power generation is performed by the controller 30 that controls driving of the electric system in the excavator 1 according to the load of the engine 11 and the like.

  A main pump 14 and a pilot pump 15 are connected to the output shaft of the speed reducer 13, and a control valve 17 is connected to the main pump 14 via a high pressure hydraulic line 16. The control valve 17 is a device that controls the hydraulic system in the excavator 1. In addition to the hydraulic motors 2A and 2B for driving the traveling mechanism 2 shown in FIG. 13, a boom cylinder 7, an arm cylinder 8 and a bucket cylinder 9 are connected to the control valve 17 via a high pressure hydraulic line. The control valve 17 controls the hydraulic pressure supplied to them according to the operation input of the driver.

  An operation device 26 (operation means) is connected to the pilot pump 15 via a pilot line 25. The operating device 26 is an operating device for operating the turning electric motor 21, the traveling mechanism 2, the boom 5, the arm 6, and the bucket 10, and is operated by an operator. A control valve 17 is connected to the operating device 26 via a hydraulic line 27, and a pressure sensor 29 is connected via a hydraulic line 28. The operating device 26 converts the hydraulic pressure (primary hydraulic pressure) supplied through the pilot line 25 into a hydraulic pressure (secondary hydraulic pressure) corresponding to the operation amount of the operator and outputs the hydraulic pressure. The secondary hydraulic pressure output from the operating device 26 is supplied to the control valve 17 through the hydraulic line 27 and detected by the pressure sensor 29.

  When an operation for turning the turning mechanism 3 is input to the operating device 26, the pressure sensor 29 detects this operation amount as a change in the oil pressure in the hydraulic line 28. The pressure sensor 29 outputs an electrical signal indicating the hydraulic pressure in the hydraulic line 28. This electric signal is input to the controller 30 and used for driving control of the turning electric motor 21.

  The controller 30 is configured by an arithmetic processing unit including a CPU (Central Processing Unit) and an internal memory, and is realized by the CPU executing a drive control program stored in the internal memory. The controller 30 receives operation inputs from various sensors and the operation device 26, and performs drive control of the inverters 18A, 18B, 18C, the power storage means 101, and the like.

  The hydraulic motor 310 is configured to be rotated by oil discharged from the boom cylinder 7 when the boom 5 is lowered, and is provided to convert energy when the boom 5 is lowered according to gravity into rotational force. It has been. The hydraulic motor 310 is provided in the hydraulic pipe 7 </ b> A between the control valve 17 and the boom cylinder 7. The electric power generated by the boom regenerative generator 300 is supplied as regenerative energy to the power storage means 101 via the inverter 18B.

  The turning electric motor 21 is provided in the turning mechanism 3 in FIG. 13 and rotates the upper turning body 4. The turning electric motor 21 is an AC electric motor and is a power source of the turning mechanism 3 for turning the turning body 4. A resolver 22, a mechanical brake 23, and a turning speed reducer 24 are connected to the rotating shaft 21 </ b> A of the turning electric motor 21. The turning inverter 18 </ b> C receives electric power from the power storage means 101 and drives the turning electric motor 21. Further, during the regenerative operation of the turning electric motor 21, the electric power from the turning electric motor 21 is collected in the power storage means 101.

  When the turning electric motor 21 performs a power running operation, the rotational force of the rotational driving force of the turning electric motor 21 is amplified by the turning speed reducer 24, and the turning body 4 is subjected to acceleration / deceleration control to perform rotational motion. Further, due to the inertial rotation of the swing body 4, the rotation speed is increased by the swing speed reducer 24 and transmitted to the swing electric motor 21 to generate regenerative power.

  The resolver 22 is a sensor that detects the rotation position and rotation angle of the rotation shaft 21A of the turning electric motor 21, and mechanically connects to the turning electric motor 21 to detect the rotation angle and rotation direction of the rotation shaft 21A. When the resolver 22 detects the rotation angle of the rotation shaft 21A, the rotation angle and the rotation direction of the turning mechanism 3 are derived. The mechanical brake 23 is a braking device that generates a mechanical braking force, and mechanically stops the rotating shaft 21 </ b> A of the turning electric motor 21 according to a command from the controller 30. The turning speed reducer 24 is a speed reducer that reduces the rotational speed of the rotating shaft 21 </ b> A of the turning electric motor 21 and mechanically transmits it to the turning mechanism 3.

  Next, the electric system will be described in detail. The electric system mainly includes a controller 30, a power conversion device 100, and inverters 18A to 18C.

(assist)
The motor generator 12 is connected to the secondary side (output) end of the assist inverter 18A. The inverter 18A controls the operation of the motor generator 12 based on a command from the assist inverter controller 30A that is a part of the controller 30.

(Boom regeneration)
A boom regeneration generator 300 is connected to the secondary side (output) end of the inverter 18B. As described above, the boom regeneration generator 300 is an electric working element that converts potential energy into electrical energy when the boom 5 is lowered by the action of gravity. The inverter 18 </ b> B is controlled by the boom regeneration inverter controller 30 </ b> B of the controller 30, converts the electric energy generated by the boom regeneration generator 300 into DC power, and collects it in the power conversion device 100.

(Turning)
The turning electric motor 21, the resolver 22, the mechanical brake 23, the turning speed reducer 24, the turning inverter 18 </ b> C and the turning inverter controller 30 </ b> C that is a part of the controller 30 constitute an electric turning device 500.
The turning electric motor 21 is AC driven by the turning inverter 18C in accordance with a PWM (Pulse Width Modulation) control command. As the turning electric motor 21, for example, a magnet-embedded IPM motor is suitable.

  The turning inverter controller 30C receives a rotation speed command corresponding to the operation input, and controls the turning inverter 18C so that the turning speed of the turning electric motor 21 detected by the resolver 22 matches the rotation speed command.

(Power supply)
The power storage unit 101 and the converter controller 30 </ b> D that is a part of the controller 30 constitute the power conversion device 100. The power storage means 101 includes, for example, a battery as a storage battery, a step-up / down converter (bidirectional DC / DC converter) that controls charging / discharging of the battery, and a DC bus including positive and negative DC wirings (not shown). ) As the electric storage device, a rechargeable secondary battery such as a lithium ion battery, a capacitor, or any other form of power source capable of transferring power may be used. The primary side (DC input) of each of the inverters 18A to 18C is connected to the DC bus. The controller 30D controls the bidirectional DC / DC converter so that the DC link voltage generated on the DC bus becomes a predetermined voltage level. The power conversion device 100 boosts the bidirectional DC / DC converter when the motor generator 12 or the like performs a power running operation, and operates the bidirectional DC / DC converter when the motor generator 12 or the like performs a regenerative operation. The electric power generated by the motor generator 12 is collected in the battery by performing a step-down operation.

  That is, when the inverter 18A causes the motor generator 12 to perform a power running operation, necessary power is supplied from the battery and the step-up / down converter to the motor generator via the DC bus. When the motor generator 12 is regeneratively operated, the battery is charged with the electric power generated by the motor generator 12 via the DC bus and the step-up / down converter. The switching control between the step-up / step-down converter and the step-down operation is performed by the converter controller 30D based on the DC bus voltage value, the battery voltage value, and the battery current value. As a result, the DC bus can be maintained in a state of being stored at a predetermined constant voltage value.

  The above is the overall configuration of the excavator 1. Subsequently, the bidirectional DC / DC converter 110 according to the embodiment can be suitably used for the power storage unit 101. FIG. 15 is a perspective view showing a layout of the bidirectional DC / DC converter 110. The bidirectional DC / DC converter 110 uses the reactor unit 130 of FIG. The IPM 114 that is the switching circuit 112 and the reactor unit 130 are arranged side by side on the base plate of the housing 200. The P pole terminal 116 of the IPM 114 is electrically and mechanically connected to the bus bar 122 corresponding to the DC bus 104. The switching terminal (AC terminal) 118 of the IPM 114 and the second ports P2_1 and P2_2 of the reactors L1 and L2 are electrically and mechanically connected via the bus bar 124. The N pole terminal 117 of the IPM 114 is connected to the N pole bus bar 126.

  In the above, this invention was demonstrated based on the Example. It is understood by those skilled in the art that the present invention is not limited to the above-described embodiment, and various design changes are possible, and various modifications are possible, and such modifications are within the scope of the present invention. It is a place. Hereinafter, such modifications will be described.

  In the embodiment, the excavator 1 is shown as an example of the hybrid-type construction machine according to the present invention. However, as another example of the hybrid-type construction machine of the present invention, a lifting magnet vehicle, a crane, or the like having a turning mechanism is given. It is done.

  The bidirectional DC / DC converter 110 can also be suitably used for a secondary battery charge / discharge device, a household power storage system, and the like.

  The power conversion device is not limited to the bidirectional DC / DC converter, and may be a step-down converter or a step-up converter. In this case, the power conversion device can also be used as a general and general-purpose power source that supplies a large current.

DESCRIPTION OF SYMBOLS 1 ... Excavator, 2 ... Traveling mechanism, 2A ... Hydraulic motor, 3 ... Turning mechanism, 4 ... Turning body, 4a ... Driver's cab, 5 ... Boom, 6 ... Arm, 7 ... Boom cylinder, 7A ... Hydraulic pipe, 8 ... Arm Cylinder, 9 ... Bucket cylinder, 10 ... Bucket, 11 ... Engine, 12 ... Motor generator, 13 ... Reduction gear, 14 ... Main pump, 15 ... Pilot pump, 16 ... High pressure hydraulic line, 17 ... Control valve, 18, 18A , 18B ... inverter, 18C ... turning inverter, 21 ... turning electric motor, 21A ... rotating shaft, 22 ... resolver, 23 ... mechanical brake, 24 ... turning speed reducer, 25 ... pilot line, 26 ... operating device, 27, 28 ... Hydraulic line, 29 ... Pressure sensor, 30 ... Controller, 30A, 30B, 30C ... Inverter controller, 30D ... Converter Controller 100 ... Power supply device 101 ... Power storage means 102 ... Capacitor 104 ... DC bus 110 ... Bidirectional DC / DC converter 112 ... Switching circuit C1 ... Smoothing capacitor 120 ... Controller 130 ... Reactor unit 132 DESCRIPTION OF SYMBOLS ... Core, 134 ... Conductor, 300 ... Boom regeneration generator, 310 ... Hydraulic motor, 500 ... Electric turning apparatus.

Claims (6)

DC bus,
A switching circuit connected to the DC bus;
A plurality of M (M ≧ 2) reactors connected to the switching circuit to form parallel current paths and having substantially equal inductances;
With
The M reactors are
A plurality of N (N ≧ M) cores;
M wires,
With
Each of the M conductive wires is wound around a plurality of p cores (2 ≦ p ≦ N) of the N cores to form p coils electrically connected in series,
A plurality of q (2 ≦ q) coils wound around the same core have substantially the same number of turns and generate magnetic flux in the same direction.   The power converter according to claim 1, wherein M × p = N × q.   The power converter according to claim 1 or 2, wherein M = q.   The power conversion device according to claim 1, wherein q = 2.   The power converter according to any one of claims 1 to 4, wherein the N cores are annular cores. An electric motor,
An inverter for driving the electric motor;
A capacitor,
The power conversion device according to any one of claims 1 to 5, wherein power is exchanged between the capacitor and the inverter.
A work machine comprising:

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