JP6316269B2 - Power converter - Google Patents

Description

  The present invention relates to a power converter including a DC / DC converter using a semiconductor switching element and passive components, and an inverter.

  As a conventional power converter, a DC / DC converter composed of a reactor and a semiconductor switching element, means for detecting the temperature of the reactor and suppressing the voltage of the DC / DC converter, and indirectly suppressing the current of the reactor There is a power conversion device having a means for performing (see, for example, Patent Document 1 below).

  Further, as a conventional DC / DC converter, it has two or more switching units composed of two semiconductor switching elements that perform a switching operation, and all the semiconductor switching elements of each switching unit are connected in series, and the energy transfer capacitor And a reactor having a reactor, and is known to perform DC / DC conversion using charging / discharging of an energy transfer capacitor by switching operation of a semiconductor switching element of each switching unit, and a low withstand voltage semiconductor switching element It is known that the ratio between the input voltage and the output voltage can be adjusted by changing the on-duty of the semiconductor switching element (for example, see Patent Document 2 below).

  In the power conversion device of Patent Document 1 below, a DC / DC converter using a switching element and a reactor and an inverter are used, and means for suppressing the voltage of the DC / DC converter according to the detected temperature of the reactor, or indirectly the current of the reactor It has a means to suppress.

  Moreover, a small reactor can be used by applying the conventional DC / DC converter of patent document 2 below.

JP 2009-219200 A Japanese Patent No. 5189620

Thierry A. Meynard et al., “Multicell Converters: Basic Concepts and Industry Applications”, IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL.49, NO.5, OCTOBER 2002

In the conventional power converter, the reactor can be downsized. However, even in the conventional power converter, the reactor is large and heavy, and there is a problem that the power converter itself becomes large and heavy.
In addition, since the output of the capacitor included in the power converter is not limited due to temperature rise, it is necessary to use a capacitor with a large current rating. For this reason, there is a problem that the capacitor is increased in size and weight, and the power converter itself is increased in size and weight.

  The present invention has been made in order to solve such problems, and is an improved power conversion device that can use a small and lightweight reactor or capacitor with a small current / power rating or a reactor and a capacitor. It is intended to provide.

The present invention relates to a DC / DC converter including a first semiconductor switching element group that performs a switching operation, a reactor, and a capacitor, and an output of the DC / DC converter is converted into an alternating current by switching of the second semiconductor switching element group. And controlling the inverter supplied to the electric rotating machine, the DC / DC converter and the inverter, and depending on the temperature of the reactor of the DC / DC converter and the DC voltage to be boosted, the output of the inverter or the inverter A control unit that limits a current converted by the DC / DC converter by limiting a torque output of the connected electric rotating machine, wherein the first semiconductor switching element group includes: , Two each performing a complementary switching operation Consist of two switching units composed of a conductor switching elements, each of which switching units of the semiconductor switching elements are all connected in series, one of the semiconductor switching elements of each switching unit to one side of the voltage terminal of the central Are connected in series, the other semiconductor switching element of each switching unit is connected in series to the other side of the central voltage terminal, and a connection point between the semiconductor switching elements on one side of the central voltage terminal; The capacitor is connected to a connection point between the semiconductor switching elements on the other side, the reactor is connected in series between the central voltage terminal and the power supply side, and the capacitor and the reactor are connected to the switching terminals. Switching operation of each semiconductor switching element of the unit Comprising a reactor for storing electrical energy for more charging and discharging is the energy transfer capacitor and the voltage converter, in the power converter or the like.

  According to the present invention, it is possible to provide an improved power conversion device or the like that can use a small and light reactor or capacitor having a small current / power rating or a reactor and a capacitor.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram including the electric circuit diagram which shows the structure of the power converter device which concerns on Embodiment 1 of this invention. It is a wave form diagram of each part for demonstrating operation | movement of the DC / DC converter of the power converter device which concerns on Embodiment 1 of this invention. It is a wave form diagram of each part for demonstrating operation | movement of the DC / DC converter of the power converter device which concerns on Embodiment 1 of this invention. It is a figure showing the temperature rise of the semiconductor switching element of the DC / DC converter of the power converter device which concerns on Embodiment 1 of this invention, a reactor, and a capacitor | condenser. It is a functional block diagram showing the internal structure of the control part of the power converter device which concerns on Embodiment 1 of this invention. It is a block diagram including the electric circuit diagram which shows the structure of the power converter device which concerns on Embodiment 2 of this invention. It is a functional block diagram showing the internal structure of the control part of the power converter device which concerns on Embodiment 2 of this invention.

  Hereinafter, a power converter according to the present invention will be described with reference to the drawings according to each embodiment. In each embodiment, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.

Embodiment 1 FIG.
1 is a configuration diagram including an electric circuit diagram showing a configuration of a power conversion device according to Embodiment 1 of the present invention. The power conversion device according to the first embodiment includes a DC / DC converter 10, an inverter 11, and a control unit 20. The DC / DC converter 10 converts a DC voltage V1 input between the voltage terminal VL and the voltage terminal VN into a boosted DC voltage V2, and outputs it between the voltage terminal VH and the voltage terminal VN. A bidirectional DC / DC converter having a step-down function that converts a DC voltage V2 input between a terminal VH and a voltage terminal VN into a stepped-down DC voltage V1 and outputs the voltage between the voltage terminal VL and the voltage terminal VN. .

  The inverter 11 is an inverter that outputs a DC voltage V2 between the voltage terminal VH and the voltage terminal VN to the three-phase output terminals Vu, Vv, and Vw as a three-phase AC. A voltage terminal VL and a voltage terminal VN of the power conversion device are connected to the battery B, and a three-phase output terminal of the power conversion device is connected to an electric rotating machine MG including a generator, a motor, and the like to supply a three-phase alternating current.

The control unit 20
A function of controlling the three-phase current of the inverter 11,
A function of controlling the DC voltage V2 of the DC / DC converter 10;
A function of limiting the torque of the electric rotating machine MG and the load output of the inverter 11 so as to limit the current of the DC / DC converter 10 based on the reactor temperature and the capacitor temperature;
Have

  In FIG. 1, the main circuit of the DC / DC converter 10 includes smoothing capacitors C1 and C2 that smooth the input / output DC voltages V1 and V2, a smoothing capacitor C0 that functions as an energy transfer capacitor, and a plurality of semiconductor switching elements S1a. , S1b, S2a, S2b (first semiconductor switching element group) and a reactor L for storing electric energy for voltage conversion. The semiconductor switching elements S1a and S1b perform a complementary switching operation to constitute the switching unit SU1. In addition, the semiconductor switching elements S2a and S2b also perform a complementary switching operation to configure the switching unit SU2.

  Each of the semiconductor switching elements S1a, S1b, S2a, S2b is composed of an IGBT (insulated gate bipolar transistor) and a diode connected in antiparallel thereto. The IGBT of each semiconductor switching element S1a, S1b, S2a, S2b has a collector terminal, an emitter terminal, and a gate terminal, respectively. The diode of each semiconductor switching element S1a, S1b, S2a, S2b is the semiconductor switching element S1a. , S1b, S2a, and S2b are connected in antiparallel between the collector terminal and the emitter terminal of the IGBT such that the anode terminal is connected to the emitter terminal.

Details of connection of the DC / DC converter 10 will be described.
The IGBT emitter terminal of the semiconductor switching element S1b is connected to the voltage terminal VM, and its collector terminal is connected to the high voltage side terminal of the smoothing capacitor (energy transfer capacitor) C0.
The IGBT emitter terminal of the semiconductor switching element S1a is connected to the low voltage side terminal of the smoothing capacitor (energy transfer capacitor) C0, and its collector terminal is connected to the voltage terminal VM.
The IGBT emitter terminal of the semiconductor switching element S2b is connected to the high voltage side terminal of the smoothing capacitor (energy transfer capacitor) C0, and its collector terminal is connected to the high voltage side terminal of the smoothing capacitor C2.
The IGBT emitter terminal of the semiconductor switching element S2a is connected to the low voltage side terminal of the smoothing capacitor C2, and its collector terminal is connected to the low voltage side terminal of the smoothing capacitor (energy transfer capacitor) C0.

  The low voltage side terminal of the smoothing capacitor C1 is connected to the voltage terminal VN, and the high voltage side terminal of the smoothing capacitor C1 is connected to the voltage terminal VL. The low voltage side terminal of the smoothing capacitor C2 is connected to the voltage terminal VN, and the high voltage side terminal of the smoothing capacitor C2 is connected to the voltage terminal VH. One terminal of the reactor L is connected to the voltage terminal VL, and the other terminal is connected to the voltage terminal VM.

The IGBT of the semiconductor switching element S1a is determined by the gate signal Gate1a output from the control unit 20.
The IGBT of the semiconductor switching element S1b is determined by the gate signal Gate1b output from the control unit 20.
The IGBT of the semiconductor switching element S2a is determined by the gate signal Gate2a output from the control unit 20.
The IGBT of the semiconductor switching element S2b performs a switching operation by a gate signal Gate2b output from the control unit 20.
The semiconductor switching elements S1a, S1b, S2a, and S2b are turned on when the gate signals Gate1a, Gate1b, Gate2a, and Gate2b are high “H” signals, and the gate signals Gate1a, Gate1b, Gate2a, and Gate2b are low “L” signals. Sometimes it turns off.

Details of the connection of the inverter 11 will be described.
The semiconductor switching elements Sul, Suh, Svl, Svh, Swl, and Swh (second semiconductor switching element group) are respectively IGBTs (insulated gates) in the same manner as the semiconductor switching elements S1a, S2a, S1b, and S2b of the DC / DC converter 10. Type bipolar transistor) and a diode connected in antiparallel thereto.

The emitter terminal of the IGBT of the semiconductor switching element Sul on the U-phase lower arm side is connected to the voltage terminal VN, and its collector terminal is connected to the three-phase output terminal Vu.
The emitter terminal of the IGBT of the semiconductor switching element Suh on the U-phase upper arm side is connected to the three-phase output terminal Vu, and its collector terminal is connected to the voltage terminal VH.
The emitter terminal of the IGBT of the semiconductor switching element Svl on the V-phase lower arm side is connected to the voltage terminal VN, and its collector terminal is connected to the three-phase output terminal Vv.
The emitter terminal of the IGBT of the semiconductor switching element Svh on the V-phase upper arm side is connected to the three-phase output terminal Vv, and its collector terminal is connected to the voltage terminal VH.
The emitter terminal of the IGBT of the semiconductor switching element Swl on the W-phase lower arm side is connected to the voltage terminal VN, and its collector terminal is connected to the three-phase output terminal Vw.
The emitter terminal of the IGBT of the semiconductor switching element Swh on the W-phase upper arm side is connected to the three-phase output terminal Vw, and its collector terminal is connected to the voltage terminal VH.

The IGBT of the semiconductor switching element Sul is determined by the gate signal Gateul output from the control unit 20.
The IGBT of the semiconductor switching element Suh is determined by the gate signal Gateuh output from the control unit 20.
The IGBT of the semiconductor switching element Svl is determined by the gate signal Gatev1 output from the control unit 20.
The IGBT of the semiconductor switching element Svh is determined by the gate signal Gatevh output from the control unit 20.
The IGBT of the semiconductor switching element Swl is determined by the gate signal Gatewl output from the control unit 20.
The IGBT of the semiconductor switching element Swh performs a switching operation by the gate signal Gatewh output from the control unit 20.

The voltage sensor SnsV1 detects the voltage value of the DC voltage V1 between the voltage terminals VL-VN,
The voltage sensor SnsV2 detects the voltage value of the DC voltage V2 between the voltage terminals VH and VN,
Three-phase current sensors SnsIu, SnsIv, SnsIw detect three-phase AC three-phase currents Iu, Iv, Iw between the three-phase output terminals Vu, Vv, Vw of the inverter 11 and the electric rotating machine MG,
The temperature sensor SnsTL detects the temperature TmpL of the reactor L,
The temperature sensor SnsTC detects the temperature TmpC of the capacitor C0,
The rotation angle sensor Snsθm detects the rotation angle θm of the electric rotating machine MG,
Each is input to the control unit 20.
Further, the torque command value Trq * of the electric rotating machine MG and the DC voltage command value V2 * are input to the control unit 20 from the outside.

  When the reactor temperature TmpL and the capacitor temperature TmpC are low, the gate signals Gateul, Gateuh, Gatevl, Gatevh, Gatewl, and Gatewh of the inverter 11 are controlled so that the torque of the electric rotating machine MG becomes equal to the torque command value Trq *. Further, the gate signals Gate1a, Gate1b, Gate2a, and Gate2b of the DC / DC converter 10 are controlled so that the DC voltage V2 becomes equal to the DC voltage command value V2 *.

Next, the operation of converting the DC voltage of the DC / DC converter 10 into a DC voltage that is stepped up or stepped down will be described.
In the steady state, the average voltage V0 of the smoothing capacitor (energy transfer capacitor) C0 is ½ of the DC voltage V2, that is, V2 / 2. Since the smoothing capacitor C2 is charged with the DC voltage V2, the applied voltage to each of the semiconductor switching elements S1a, S1b, S2a, S2b is approximately V2 / 2. In addition, as described in Non-Patent Document 1, the ripple voltage applied to the reactor L is small, and the frequency of the ripple voltage applied to the reactor L is twice the switching frequency. L can be used.

  2 and 3 are waveform diagrams of respective parts for explaining the operation of the DC / DC converter 10 according to the first embodiment. FIG. 2 shows a case where the on-duty of the semiconductor switching elements S1a and S2a is 50% or more ( FIG. 3 shows the operation when the on-duty of the semiconductor switching elements S1a and S2a is smaller than 50% (Duty <50%).

  2 and 3, (a) shows the gate signals Gate1a, Gate1b, Gate2a and Gate2b, (b) shows the current of the reactor L, (c) shows the current of the smoothing capacitor (energy transfer capacitor) C0. . Note that the horizontal axis in FIGS. 2 and 3 is a common time axis.

First, the operation when the on-duty of the semiconductor switching elements S1a and S2a is 50% or more (Duty ≧ 50%) will be described below with reference to FIG.
The gate signal Gate1a and the gate signal Gate1b are complementary gate signals in which when one is a high signal, the other is a low signal, and when one is a low signal, the other is a high signal. Similarly, the gate signals Gate2a and Gate2b are complementary gate signals.

  The gate signals Gate2a and Gate2b are signals whose phases are delayed by 180 ° with respect to the gate signals Gate1a and Gate1b. Actually, when the gate signals Gate1a and Gate1b are switched from a high signal to a low signal (or from a low signal to a high signal), both gate signals are low in order to prevent a short circuit between the semiconductor switching elements S1a and S1b. There is a period in which the signal dead time is extremely short, but it is omitted for the sake of simplicity. Similarly, the gate signals Gate2a and Gate2b have a dead time of a very short period, but the description thereof is omitted.

  The semiconductor switching elements S1a, S1b, S2a, and S2b are turned on when the gate signals Gate1a, Gate1b, Gate2a, and Gate2b are high signals, respectively, and are turned off when the gate signals Gate1a, Gate1b, Gate2a, and Gate2b are low signals. Further, the ON times T1a, T1b, T2a, and T2b in one switching period of each semiconductor switching element S1a, S1b, S2a, and S2b are as follows using the switching period Ts and the on-duty duty of the semiconductor switching elements S1a and S2a. It becomes.

T1a = Duty × Ts
T1b = (1-Duty) × Ts
T2a = Duty × Ts
T2b = (1-Duty) × Ts

  A section in which the gate signal Gate1a and the gate signal Gate2a are both high signals (the gate signal Gate1b and the gate signal Gate2b are both low signals) is described as section 1. A section in which the gate signal Gate1a is a high signal (the gate signal Gate1b is a low signal) and the gate signal Gate2a is a low signal (the gate signal Gate2b is a high signal) is referred to as a section 2. A section in which the gate signal Gate1a is a low signal (the gate signal Gate1b is a high signal) and the gate signal Gate2a is a high signal (the gate signal Gate2b is a low signal) is referred to as a section 3. A section in which both gate signals Gate1a and Gate2a are low signals (both gate signals Gate1b and Gate2b are high signals) is referred to as section 4, but in FIG. 2, section 4 does not exist. In section 1 and section 4, no current flows through the smoothing capacitor (energy transfer capacitor) C0.

  When the on-duty of the semiconductor switching elements S1a and S2a is larger than 50% (Duty> 50%), as shown in FIG. 2, one period is constituted by section 1, section 2, and section 3, and this one period Does not exist in section 4. When the on-duty of the semiconductor switching elements S1a and S2a is 50% (Duty = 50%), the section 1 does not exist, but the operations in the following sections 2 and 3 are the same.

First, in section 3, since the gate signals Gate1b and Gate2a become high signals and the semiconductor switching elements S1b and S2a are turned on, the reactor L and the smoothing capacitor (energy transfer capacitor) C0 are connected in series, Current flows. Therefore, a current similar to that of the reactor L flows through the smoothing capacitor (energy transfer capacitor) C0.
Capacitor C1 → Reactor L → Semiconductor switching element S1b → Capacitor C0 → Semiconductor switching element S2a

In section 2, since semiconductor switching elements S1a and S2b are turned on, reactor L and smoothing capacitor (energy transfer capacitor) C0 are connected in series, and current flows through the following path. For this reason, the current in the direction opposite to that of the section 3 flows with respect to the reactor L through the smoothing capacitor (energy transfer capacitor) C0.
Capacitor C1 → Reactor L → Semiconductor switching element S1a → Capacitor C0 → Semiconductor switching element S2b → Capacitor C2

In section 1, since semiconductor switching elements S1a and S2a are turned on and current flows through the following path, no current flows through smoothing capacitor (energy transfer capacitor) C0.
Capacitor C1 → Reactor L → Semiconductor switching element S1a → Semiconductor switching element S2a

  The times Ts2 and Ts3 of the sections 2 and 3 in one switching cycle are as follows.

Ts2 = (1-Duty) × Ts
Ts3 = (1-Duty) × Ts

  The current of the reactor L can be divided into a direct current IL and a ripple current ΔIL. The ripple current ΔIL represents the magnitude of the current from the trough to the peak of the triangular wave current of the reactor L. The reactor ripple current ΔIL is generated by switching of the semiconductor switching element of the DC / DC converter 10, is determined by the voltages V 1, V 2, the switching period Ts, and the inductance value L of the reactor, and is represented by the following formula (1).

    ΔIL = [{V1 · (V2-2 × V1)} / (V2 × L)] · (Ts / 2) (1)

  The reactor ripple current ΔIL flows through the capacitor C1. Therefore, direct current IL of reactor L is equal to current I 1 flowing from battery B to DC / DC converter 10. Here, the current I1 flowing from the battery B to the DC / DC converter 10 is referred to as a primary current of the DC / DC converter 10.

  Further, the (effective value) current Ic0 of the smoothing capacitor (capacitor for energy transfer) C0 is calculated by integrating one period, and is expressed by the following equation (2).

_{I C0 = √ [2 × (} 1-Duty) × {I1 2 + (ΔIL 2/12)}] (2)

  According to Equation (2), it is understood that the current Ic0 of the smoothing capacitor C0 depends on the primary current I1 of the DC / DC converter 10 when the on-duty is 50% or more (Duty ≧ 50%). Is done.

  The relationship between the on-duty duty and the input / output DC voltages V1 and V2 will be described. In a steady state, the average voltage of one switching cycle between both ends of the reactor L becomes 0 when the voltage drop due to the resistance component is ignored. Therefore, the average voltage between the voltage terminals VM-VN and the DC voltage V1 are equal, and the following equation (3) is satisfied.

    V1 = (1-Duty) × V2 (3)

  As is apparent from the equation (3), the voltage ratio between the input / output DC voltages V1 and V2 of the DC / DC converter 10 can be controlled by controlling the on-duty duty.

  Next, the operation when the on-duty of the semiconductor switching elements S1a and S2a is smaller than 50% (Duty <50%) will be described below with reference to FIG. In this case, section 1 does not exist, and sections 2, 3, and 4 are displayed in FIG.

  When the on-duty of the semiconductor switching elements S1a and S2a is smaller than 50%, one period is constituted by the section 2, the section 3, and the section 4, and the period 1 does not exist. In sections 3 and 2, a current flows through a smoothing capacitor (energy transfer capacitor) C0. However, in section 4, no current flows through the smoothing capacitor (energy transfer capacitor) C0.

  The times Ts2 and Ts3 of the sections 2 and 3 in one switching cycle are as follows.

Ts2 = Duty × Ts
Ts3 = Duty × Ts

  The current of the reactor L can be divided into a direct current IL and a ripple current ΔIL as in the case where the on-duty is larger than 50%. The reactor ripple current ΔIL is generated by switching of the semiconductor switching element of the DC / DC converter 10, is determined by the voltages V 1, V 2, the switching period Ts, and the inductance value L of the reactor, and is represented by the following formula (4).

    ΔIL = {(2 × V1−V2) · (V2−V1)} / (V2 × L)} · (Ts / 2) (4)

  The reactor ripple current ΔIL flows through the capacitor C1. Therefore, direct current IL of reactor L is equal to primary side current I1 of DC / DC converter 10.

  Further, the (effective value) current Ic0 of the smoothing capacitor (energy transfer capacitor) C0 is calculated as shown in the following formula (5) when calculated by integrating one period.

_{I C0 = √ [2 × Duty} × {(I1 2 + (ΔIL 2/12)}] (5)

  According to the equation (5), when the on-duty is smaller than 50% (Duty <50%), the current Ic0 of the smoothing capacitor C0 depends on the primary side current I1 of the DC / DC converter 10. Is understood.

  Further, the relationship between the duty signal Duty and the input / output DC voltages V1 and V2 is expressed by the following formula (6), similarly to the case where the on-duty of the semiconductor switching elements S1a and S2a is 50% or more.

    V1 = (1-Duty) × V2 (6)

  As is apparent from the equation (6), even when the on-duty duty of the semiconductor switching elements S1a and S2a is smaller than 50%, the voltage ratio of the input / output DC voltages V1 and V2 is controlled by controlling the duty duty. be able to.

  From the above, the DC current IL of the reactor L becomes equal to the primary current I1 of the DC / DC converter 10 regardless of the on-duty duty of the semiconductor switching elements S1a and S2a. Further, the ripple current ΔIL of the reactor L depends on the voltages V1 and V2 and the switching cycle Ts of the semiconductor switching element.

  The loss of the reactor is caused by the direct current IL of the reactor L and the ripple current ΔIL. The reactor loss caused by the reactor DC current IL is the DC copper loss Pcoildc generated in the coil Lcoil of the reactor L, and is expressed by Equation (7) using the winding resistance RL.

Pcoildc = RL × I1 ² (7)

  The reactor loss caused by the ripple current that is the AC component of the reactor includes the iron loss Pcore that occurs in the core Lcore of the reactor L and the AC copper loss Pcoilac that is the eddy current loss that occurs in the coil Lcoil.

  Further, according to the equations (2) and (5), the current Ic0 of the smoothing capacitor C0 depends on the primary side current I1 of the DC / DC converter 10, the ripple current ΔIL of the reactor L, and the duty. The ripple current ΔIL of the reactor L depends on the voltages V1, V2 and the switching cycle Ts of the semiconductor switching element, and the Duty depends on the voltages V1, V2. Therefore, the current Ic0 of the capacitor C0 depends on the primary side current I1 of the DC / DC converter 10, the voltages V1 and V2, and the switching period Ts of the semiconductor switching element.

  The loss Pc0 of the capacitor C0 is expressed by the equation (8) using the current Ic0 of the capacitor C0 and the resistor RC0 of the capacitor C0.

Pc0 = RC0 × Ic0 ² (8)

  Thus, the loss of the reactor L and the capacitor C0 depends on the primary side current I1 of the DC / DC converter 10. When the absolute value of the primary current I1 of the DC / DC converter 10 increases, the loss of the reactor L and the capacitor C0 increases, and when the absolute value of the primary current I1 of the DC / DC converter 10 decreases, the reactor L, The loss of the capacitor C0 is reduced.

  The same applies to the temperature rise of the reactor L and the capacitor C0. If the absolute value of the primary current I1 of the DC / DC converter 10 is large, the temperature rise increases, and the absolute value of the primary current I1 of the DC / DC converter 10 is large. If is small, the temperature rise is small.

  Next, the temperature rise of the semiconductor switching element, the reactor, and the capacitor of the DC / DC converter will be described below. FIG. 4 is a diagram illustrating a temperature rise of semiconductor switching elements S1a, S1b, S2a, S2b, reactor L, and capacitor C0 of DC / DC converter 10 according to the first embodiment. 4, (a) is the primary side current I1 of the DC / DC converter 10, (b) is the IGBT temperature of the semiconductor switching element S1a, (c) is the temperature of the reactor L, and (d) is the temperature of the capacitor C0. Are shown respectively. The horizontal axis in FIG. 4 is a common time axis.

  FIG. 4 shows a case where the power converter changes in a step shape from a non-energized state (a state where no voltage / current is applied) to an energized state (a state where voltage / current is applied). The primary side current I1 of the DC / DC converter 10 changes from 0 A in a stepped manner to a certain constant current. The temperature of the IGBT of the semiconductor switching element S1a gradually increases after the energized state and rises to a certain temperature that is in a thermal saturation state. Similarly, also about the temperature of the reactor L, after it will be in an electricity supply state, temperature will rise gradually and will also rise to the fixed temperature which is a heat saturation state. Similarly, the temperature of the capacitor C0 also gradually increases after the energized state, and rises to a certain temperature that is a thermal saturation state.

  Even in a thermal saturation state, it is possible to energize continuously as long as it is below the heat resistance temperature of each component (semiconductor switching element, reactor, capacitor). The semiconductor switching element is efficiently cooled by bonding the semiconductor switching element to one surface of a ceramic substrate having high thermal conductivity and thermally connecting a water-cooled heat sink (water cooling mechanism) to the opposite surface of the ceramic substrate. be able to.

On the other hand, since the reactor L has a configuration in which the magnetic core Lcore is wound around the coil Lcoil, it is difficult to efficiently cool the magnetic core Lcore and the coil Lcoil. Similarly, the capacitor C0 has a configuration in which the electrode C0ele and the dielectric film C0flm are wound, so that it is difficult to efficiently cool the capacitor C0.
When the reactor L and the capacitor C0 capable of continuously energizing the maximum rated current of the DC / DC converter 10 are realized, the reactor L and the capacitor C0 are increased in size and weight, and the power converter itself is also increased in size. There is a problem of increasing weight. Therefore, in the power conversion device of the first embodiment, a small and lightweight reactor L whose continuous rated current is smaller than the continuous rated current of the semiconductor switching element of the DC / DC converter 10 in order to reduce the size and weight. Or a capacitor C0.

  The reactor L of the present embodiment includes a magnetic core Lcore, a coil Lcoil wound around the magnetic core Lcore, a reactor case Lcase that stores the magnetic core Lcore and the coil Lcoil, and a core Lcore and the coil Lcoil. The reactor case Lcase is made of a podding resin Lresin, and the magnetic core Lcore and the coil Lcoil are all or at least partially covered with the podding resin Lresin. By covering the magnetic core Lcore and the coil Lcoil with the padding resin Lresin, the heat capacity of the reactor L is increased, and the time until the reactor is thermally saturated is increased. Therefore, even if a small and lightweight reactor with a small continuous rated current is used, the maximum rated current of the DC / DC converter 10 can be energized as long as the temperature of the reactor rises to the heat resistance temperature of the reactor. It becomes.

  In addition, the capacitor C0 of the present embodiment has a configuration in which the electrode C0ele and the dielectric film C0flm are wound, and the bill body of the electrode C0ele and the dielectric film C0flm is accommodated in the capacitor case C0case, and the electrode C0ele and the dielectric All or part of the film C0flm is covered with a podging resin C0resin cast in a capacitor case. By covering the electrode C0ele and the dielectric film C0flm with the padding resin C0resin, the heat capacity of the capacitor is increased, and the time until the capacitor is thermally saturated is increased. Therefore, even if a small and lightweight capacitor C0 having a small continuous rated current is used, the maximum rated current of the DC / DC converter can be applied as long as the temperature of the capacitor C0 rises to the heat resistant temperature of the capacitor. It becomes possible.

  Here, when the temperature rise in the thermal saturation state is 100%, the time during which the temperature rise is 63% (= 1−EXP (−1)) after the start of energization is called the thermal time constant (τ). . With respect to the reactor L, by covering the magnetic core Lcore and the coil Lcoil with the podding resin Lresin, the thermal time constant τL of the reactor L is the time constant τS of the semiconductor switching elements (IGBTs and diodes of S1a, S1b, S2a, S2b). It can be set to a larger value.

  Also for the capacitor C0, the electrode C0ele and the dielectric film C0flm are covered with the padding resin C0resin, so that the thermal time constant τC of the capacitor C0 is the time constant τS of the semiconductor switching elements (IGBT and diode of S1a, S1b, S2a, S2b). It can be set to a larger value.

  When the continuous rated current of the semiconductor switching elements (S1a, S1b, S2a, S2b IGBT and diode) is the same as the continuous rated current of the DC / DC converter 10, the semiconductor switching elements (S1a, S1b, S2a, S2b IGBTs) Since the thermal time constants (τL, τC) of the reactor L and the capacitor C0 are larger than the thermal time constant τS of the semiconductor switching element even if the diode) is thermally saturated, the small and lightweight reactor L with a small continuous rated current Even if the capacitor C0 is used, a current larger than the continuous rated current of the reactor L and the capacitor C0 can be supplied until the temperature of the reactor L and the capacitor C0 rises to the heat resistant temperature.

Next, the detail of the control part 20 of a power converter device is demonstrated below.
As described above, the control unit 20 includes
A detection voltage (DC voltage) V1 that is an output of a voltage sensor SnsV1 that detects a voltage V1 between the voltage terminals VL and VN;
A detection voltage (DC voltage) V2 that is an output of a voltage sensor SnsV2 that detects a voltage V2 between the voltage terminals VH and VN;
A detected temperature TmpL that is an output of a temperature sensor SnsTL that detects the temperature TmpL of the reactor L;
A detection temperature TmpC that is an output of a temperature sensor SnsTC that detects a temperature TmpC of the capacitor C0;
Detection that is the output of current sensors SnsIu, SnsIv, and SnsIw that detect three-phase currents Iu, Iv, and Iw between the voltage terminals (three-phase output terminals) Vu, Vv, and Vw of the inverter 11 and the electric rotating machine MG. Currents Iu, Iv, Iw,
A detection rotation angle θm that is an output of a rotation angle sensor Snsθm that detects the rotation angle θm of the electric rotating machine MG is input.
Torque command value Trq * and voltage command value V2 * are also input to control unit 20 from the outside of the power converter.
From the control unit 20, IGBT gate signals (Gate 1 a, Gate 1 b, Gate 2 a, Gate 2 b) of the semiconductor switching element of the DC / DC converter 10 and gate signals (Gateul, Gateuh, Gatevl, Gatevh, Gatewl) of the semiconductor switching element of the inverter 11. , Gatewh) is output.

  FIG. 5 is a functional block diagram showing the internal configuration of the control unit 20. The control unit 20 includes a torque limit value calculation unit 201 in (a), a torque limit unit 202 in (b), a torque control unit 203 in (c), a voltage control unit 204 in (d), and an angular velocity calculation in (e). The unit 205 is configured.

  The torque limit value calculation unit 201 in (a) includes a current limit value calculation unit 2011, a limit power calculation unit 2012, and a limit torque calculation unit 2013. Based on the reactor temperature TmpL and the capacitor temperature TmpC, the torque limit value Trq_max is calculated. Arithmetic.

  Reactor temperature TmpL and capacitor temperature TmpC are input to current limit value calculation unit 2011, and current limit value I1max, which is a limit value of current I1, is output. Current limit value I1max is derived based on reactor temperature TmpL and capacitor temperature TmpC.

  Limit value calculation unit LT derives current limit value I1Lmax based on reactor temperature TmpL. When the reactor temperature TmpL is lower than a predetermined threshold temperature TmpLth1, the current limit value I1Lmax is the maximum current value. When the reactor temperature TmpL is equal to or higher than the threshold temperature TmpLth1 and is lower than a predetermined threshold temperature TmpLth2 (TmpLth1 <TmpLth2), the current limit value I1Lmax is set to a value smaller than the maximum current value, and the reactor temperature TmpL becomes smaller as the reactor temperature TmpL becomes higher. To do. It is set to 0 when the reactor temperature TmpL is equal to or higher than the threshold temperature TmpLth2. The threshold temperatures TmpLth1 and TmpLth2 are values determined based on the heat-resistant temperature of the reactor L.

  Similar to the reactor temperature, the limit value calculation unit CT derives the current limit value I1Cmax based on the capacitor temperature TmpC. When the capacitor temperature TmpC is lower than a predetermined threshold temperature TmpCth1, the current limit value I1Cmax is set to the maximum current value. When the capacitor temperature TmpC is equal to or higher than the threshold temperature TmpCth1 and less than a predetermined threshold temperature TmpCth2 (TmpCth1 <TmpCth2), the current limit value I1Cmax is set to a value smaller than the maximum current value, and the capacitor temperature TmpC is set to a smaller value as the temperature increases. To do. It is set to 0 when the capacitor temperature TmpC is equal to or higher than the threshold temperature TmpCth2. The threshold temperatures TmpCth1 and TmpCth2 are values determined based on the heat resistant temperature of the capacitor C0.

  In limit value determining unit MIN, current limit value I1max is derived from current limit values I1Lmax and I1Cmax, which are small values, based on reactor temperature TmpL and capacitor temperature TmpC.

  The limit power calculator 2012 receives the current limit value I1max and the voltage V1 and outputs a power limit value P2max. The power limit value P2max is a power limit on the DC voltage V2 side of the DC / DC converter 10, and is derived from the current limit value I1max and the voltage V1 which are the limit values of the current I1. The specific calculation of the power limit value P2max is derived by adding the known power conversion efficiency ηdcdc of the DC / DC converter 10 to the product of the current limit value I1max and the voltage V1. Various known factors used for control are stored or set in advance in a storage unit (not shown) in the control unit 20 (the same applies hereinafter).

The limit torque calculator 2013 receives the power limit value P2max and the angular speed ωm of the electric rotating machine MG, and outputs the torque limit value Trq_max of the electric rotating machine MG. The torque limit value Trq_max is a torque limit value of the electric rotating machine MG, and is derived from the power limit value P2max and the angular speed ωm of the electric rotating machine. Specifically, the torque limit value Trq_max is calculated by dividing the power limit value P2max by the angular velocity ωm, and adding the known power conversion efficiency ηinv of the inverter 11 and the conversion efficiency ηmg of the electric rotating machine MG to derive the result. .
The angular velocity ωm is a value derived by the angular velocity calculating unit 205 in FIG. The angular velocity calculation unit 205 receives the rotation angle θm of the electric rotating machine MG and outputs the angular velocity ωm of the electric rotating machine MG. The angular velocity ωm is derived by time differentiation of the rotation angle θm.

  The torque control value calculation unit 201 calculates and outputs a torque limit value Trq_max that limits the current value of the current I1 based on the reactor temperature TmpL and the capacitor temperature TmpC.

  The torque command value Trq * and the torque limit value Trq_max input from the outside of the control unit 20 are input to the torque limit unit 202 in FIG. 5B, and the post-limit torque command value Trq2 * is output. The absolute value of torque command value Trq * is limited to a torque limit value Trq_max or less. When the torque command value Trq * is larger than the torque limit value Trq_max, the post-limit torque command value Trq2 * becomes the same value as Trq_max. When the torque command value Trq * is smaller than (−Trq_max), the post-limit torque command value Trq2 * is (− Trq_max). When the torque command value Trq * is other than that, the post-limit torque command value Trq2 * is equal to the torque command value Trq *. The post-limit torque command value Trq2 * is limited in the range of -Trq_max to Trq_max. By limiting the post-limit torque command value Trq2 * within the range of -Trq_max to Trq_max, the absolute value of the current value I1 can be limited.

  The torque control unit 203 in FIG. 5C includes a current calculation unit 2031, a current control unit 2032, a dq-axis current calculation unit 2033, and a 3φ voltage calculation unit 2034. The torque command value Trq2 * after restriction, the angular velocity ωm, The voltage V2, the three-phase currents Iu, Iv, Iw, and the rotation angle θm are input, and the gate signals Gateul, Gateuh, Gatevl, Gatevh, Gatewl, Gatewh of the inverter 11 are output.

  The current calculation unit 2031 receives the post-restricted torque command value Trq2 *, the angular velocity ωm, and the voltage V2, and outputs dq-axis current command values Id * and Iq * of the electric rotating machine MG. Under the conditions of the angular velocity ωm and the voltage V2, the current required for the torque of the electric rotating machine MG to output the restricted torque command value Trq2 * is calculated and output as dq-axis current command values Id * and Iq *.

  The dq-axis current calculation unit 2033 receives the three-phase currents Iu, Iv, Iw and the rotation angle θm, and outputs the dq-axis currents Id, Iq. The three-phase currents Iu, Iv, and Iw that are alternating current are coordinate-converted in accordance with the rotation angle θm of the motor, and output as dq-axis currents Id and Iq that are direct current.

  The current controller 2032 receives the dq-axis current command values Id * and Iq * and the dq-axis currents Id and Iq and outputs the dq-axis voltage command values Vd * and Vq *. The dq axis voltage command values Vd * and Vq * of the inverter 11 are output so that the dq axis currents Id and Iq are equal to the dq axis current command values Id * and Iq *. The current control unit 2032 performs feedback control of the dq axis current and outputs the dq axis voltage command values Vd * and Vq * of the inverter 11.

  The 3φ voltage calculation unit 2034 receives the dq axis voltage command values Vd * and Vq *, the rotation angle θm, and the voltage V2, and outputs the gate signals Gateul, Gateuh, Gatevl, Gatevh, Gatewl, and Gatewh of the inverter 11. The dq-axis voltage command values Vd * and Vq * of the inverter 11 are coordinate-converted according to the rotation angle θm of the motor, and converted to a three-phase voltage command value that is an alternating current of the inverter 11. The gate signal of the inverter for outputting the three-phase voltage command value is calculated from the three-phase voltage command value and the voltage V2, and is output as a gate signal Gateul, Gateuh, Gatevl, Gatevh, Gatewl, Gatewh.

  The torque control unit 203 calculates dq current command values Id * and Iq * necessary for outputting the post-limit torque command value Trq2 *, and is necessary for outputting the dq current command values Id * and Iq *. dq-axis voltage command values Vd *, Vq * are calculated, and gate signals Gateul, Gateuh, Gatevl, Gatevh, Gatewl, Gatewh of the inverter necessary for outputting the dq-axis voltage command values Vd *, Vq * are calculated, Output. In this way, the torque control unit 203 calculates and outputs the gate signals Gateul, Gateuh, Gatevl, Gatevh, Gatewl, and Gatewh of the inverter for outputting the post-limit torque command value Vrq2 *.

  The voltage command value V2 * and the voltage V2 are input to the voltage control unit 204 in FIG. 5D, and gate signals Gate1a, Gate1b, Gate2a, and Gate2b of the DC / DC converter 10 are output. Feedback calculation is performed so that the voltage V2 becomes equal to the voltage command value V2 *, and gate signals Gate1a, Gate1b, Gate2a, and Gate2b are output.

The control unit 20 is summarized as follows.
In the torque limit value calculation unit 201, the torque limit unit 202, and the torque control unit 203, the absolute value of the primary side current I1 of the DC / DC converter 10 is limited based on the reactor temperature TmpL and the capacitor temperature TmpC. The rear torque command value Trq2 * and the dq-axis currents Id and Iq are limited, and inverter gate signals Gateul, Gateuh, Gatevl, Gatevh, Gatewl, and Gatewh are output.
Further, the voltage control unit 204 outputs the gate signals Gate1a, Gate1b, Gate2a, and Gate2b of the DC / DC converter 10 so that the voltage V2 becomes equal to the voltage command value V2 *.

  Further, the control unit 20 realizes the function by a single microcomputer (DSP), a digital signal processor (DSP), a field programmable gate array (FPGA), or an application-specific integrated circuit (ASIC). When the function of the control unit 20 is divided into a plurality of microcomputers or DSPs, it is necessary to communicate information between the microcomputers or the DSPs, FPGAs, and ASICs, and a delay due to communication is included. In the control unit 20, it is necessary to instantaneously limit the primary side current I1 of the DC / DC converter 10 according to the reactor temperature TmpL and the capacitor temperature TmpC. Therefore, the function of the control unit 20 is realized by a single microcomputer, DSP, FPGA, or ASIC.

  The power conversion device according to the present embodiment has two or more switching units SU composed of two semiconductor switching elements Sa and Sb that perform a switching operation, and all the semiconductor switching elements in each switching unit are in series. By using a DC / DC converter having an energy transfer capacitor and a reactor that are connected and charge / discharge by switching operation of each semiconductor switching element in each switching unit, the reactor can be reduced in size.

  In addition, a small and lightweight reactor or capacitor with a continuous current rating smaller than that of a semiconductor switching element is used, and the thermal time constant of the reactor or capacitor is set to be larger than that of the semiconductor switching element, based on the reactor temperature or capacitor temperature. In order to limit the absolute value of the current I1 of the DC / DC converter, it has a control unit that limits the load output of the inverter and the torque of the electric rotating machine. Even if it uses, if it is a short time until a reactor or a capacitor becomes high temperature, a big electric current beyond the continuous rated current of a reactor or a capacitor can be supplied. That is, by having a control unit that limits the load output of the inverter and the torque of the electric rotating machine so as to limit the absolute value of the current I1 of the DC / DC converter based on the reactor temperature and the capacitor temperature, the reactor and the capacitor For a short time until the temperature becomes high, it becomes possible to use a small and lightweight reactor and capacitor.

  In addition, in this Embodiment 1, although the case where the inverter and the electric rotating machine were one was described, DC inverter is similarly applied to the case where a plurality of inverters and the electric rotating machines are connected to the voltage terminals VH and VN. The same effect can be obtained by limiting the load output of the inverter or the torque output of the electric rotating machine so as to limit the current of the DC converter.

Embodiment 2. FIG.
FIG. 6 is a configuration diagram including an electric circuit diagram showing the configuration of the power conversion device according to Embodiment 2 of the present invention. The power conversion apparatus according to the second embodiment includes a DC / DC converter 10, an inverter 11, and a control unit 21. The power conversion device according to the second embodiment is different from the power conversion device according to the first embodiment in that the temperature sensors SnsTL and SnsTC are eliminated, and a current sensor SnsIL that measures the direct current from which the ripple current of the reactor L is removed is added. It is the same except that the control unit 20 is replaced with the control unit 21.

  In the power conversion device according to the first embodiment, a control unit that limits the load output of the inverter and the torque of the electric rotating machine so as to limit the absolute value of the current I1 of the DC / DC converter based on the reactor temperature and the capacitor temperature. Therefore, a current larger than the continuous rated current of the reactor and the capacitor can be applied for a short time until the reactor and the capacitor reach a high temperature. Therefore, a small and lightweight reactor and capacitor could be applied.

In the power conversion device according to the second embodiment, the control unit 21 estimates the reactor temperature and the capacitor temperature using the reactor current IL, and the absolute value of the current I1 of the DC / DC converter based on the estimated reactor temperature and capacitor temperature. So as to limit the load output of the inverter and the torque of the electric rotating machine. Therefore, it is possible to eliminate the temperature sensors SnsTL and SnsTC.
Further, in order to limit the absolute value of the current I1 based on the estimated temperature, the control unit for limiting the load output of the inverter and the torque of the electric rotating machine is provided. However, for a short period of time until the temperature of the reactor and the capacitor reaches a high temperature, it is possible to energize a current that is greater than the continuous rated current of the reactor and the capacitor. Therefore, a small and lightweight reactor or capacitor can be applied.

The detail of the control part 21 of a power converter device is demonstrated below.
The control unit 21 includes
A detection voltage (DC voltage) V1 that is an output of a voltage sensor SnsV1 that detects a voltage V1 between the voltage terminals VL and VN;
A detection voltage (DC voltage) V2 that is an output of a voltage sensor SnsV2 that detects a voltage V2 between the voltage terminals VH and VN;
A detection current IL that is an output of a current sensor SnsIL that detects a direct current from which the ripple current of the reactor L has been removed;
Detection currents Iu, Iv which are outputs of current sensors SnsIu, SnsIv, SnsIw for detecting three-phase currents Iu, Iv, Iw between the voltage terminals (three-phase output terminals) Vu, Vv, Vw of the inverter 11 and the electric rotating machine MG. , Iw,
A detection rotation angle θm that is an output of a rotation angle sensor Snsθm that detects the rotation angle θm of the electric rotating machine MG is input.
Torque command value Trq * and voltage command value V2 * are also input to control unit 21 from the outside of the power converter.
From the control unit 21, the IGBT gate signals (Gate1a, Gate1b, Gate2a, Gate2b) of the semiconductor switching elements of the DC / DC converter 10 and the gate signals (Gateul, Gateuh, Gatevl, Gatevh, Gatewl) of the semiconductor switching elements of the inverter 11. , Gatewh) is output.

  FIG. 7 is a functional block diagram showing the internal configuration of the control unit 21. The control unit 21 has the same torque limit value calculation unit 201 in (a), the torque limit unit 202 in (b), the torque control unit 203 in (c), the voltage control unit 204 in (d), as in FIG. In addition to the angular velocity calculation unit 205 in FIG. 7, a reactor temperature calculation unit 211 in (a1) at the top of FIG. 7 and a capacitor temperature calculation unit 212 in (a2) are added.

In the reactor temperature calculation unit 211 of (a1), a reactor (estimated) temperature TmpL that is an estimated value of the reactor temperature is calculated. Reactor temperature calculator 211 receives current IL and voltages V1 and V2 and outputs an estimated value of reactor (estimated) temperature TmpL.
Reactor temperature calculation unit 211 includes DC copper loss calculation unit 2111, AC copper loss calculation unit 2112, iron loss calculation unit 2113, (first) reactor temperature increase calculation unit 2114, and (second) reactor temperature increase calculation unit 2115. It is comprised by.
As described above, the reactor loss includes DC copper loss Pcoildc, AC copper loss Pcoilac, and iron loss Pcore.

  The DC copper loss calculation unit 2111 receives the current IL, and calculates and outputs the DC copper loss Pcoildc. Using a known reactor winding resistance RL, a DC copper loss Pcoildc is calculated as follows.

Pcoildc = RL × IL ² (7)

  The AC copper loss calculator 2112 receives the voltages V1 and V2, and calculates and outputs the AC copper loss Pcoilac. The AC copper loss Pcoilac is generated by the ripple current ΔIL. Since the ripple current ΔIL is determined by the voltages V1 and V2, the AC copper loss Pcoilac can be calculated from the voltages V1 and V2. Specifically, the ripple current ΔIL is derived by calculation from the voltages V1 and V2 using the equations (1) and (4). By storing the relationship between the ripple current ΔIL and the AC copper loss Pcoilac as a map, the AC copper loss Pcoilac can be calculated from the voltages V1 and V2.

  The iron loss calculator 2113 receives the voltages V1 and V2, and calculates and outputs the iron loss Pcore. The iron loss Pcore is caused by the ripple current ΔIL. Since the ripple current ΔIL is determined by the voltages V1 and V2, the iron loss Pcore can be calculated from the voltages V1 and V2. Similar to the AC copper loss Pcoilac, also in the iron loss Pcore, ΔIL is derived by calculation from the voltages V1 and V2. By storing the relationship between the ripple current ΔIL and the AC copper loss Pcore as a map, the AC copper loss Pcore can be calculated from the voltages V1 and V2.

  The (first) reactor temperature rise calculation unit 2114 receives a copper loss that is a value obtained by adding the DC copper loss Pcoildc and the AC copper loss Pcoilac by the addition unit ad, and calculates and outputs a temperature rise caused by the copper loss. The When the copper loss occurs, the temperature rises according to a curve with a certain time constant, so that the temperature rise calculation unit 2114 is realized by a low-pass filter calculation that simulates the temperature rise.

  The (second) reactor temperature increase calculation unit 2115 receives the iron loss Pcore, and calculates and outputs the temperature increase caused by the iron loss Pcore. When the iron loss Pcore occurs, the temperature rises according to a curve with a certain time constant. Therefore, the temperature rise calculation unit 2115 is realized by a low-pass filter calculation that simulates the temperature rise.

  By adding the output value of the temperature increase calculation unit 2114 and the output value of the temperature increase calculation unit 2115 by the addition unit ad, the temperature increase of the reactor L can be derived, and the water temperature of the cooler (not shown) from the outside is added to the temperature increase Etc., the reactor temperature TmpL is estimated by calculation.

  The capacitor temperature calculation unit 212 calculates a capacitor temperature TmpC, which is an estimated value of the capacitor temperature. The capacitor temperature calculator 212 receives the current IL and the voltages V1 and V2, and outputs a capacitor (estimated) temperature TmpC that is an estimated value. The capacitor temperature calculation unit 212 includes a capacitor loss calculation unit 2121 and a capacitor temperature increase calculation unit 2122.

The capacitor loss calculation unit 2121 receives the current IL and the voltages V1 and V2 and outputs the loss Pc0. Using equations (1), (4), (3), and (6), the reactor ripple current ΔIL and Duty are once calculated from the voltages V1 and V2. Next, the current Ic0 of the capacitor C0 is calculated from the current IL, the ripple current ΔIL, and the duty using the equations (2) and (5), and the current Ic0 and the known capacitor resistance RC0 are calculated using the equation (8). The capacitor loss Pc0 is derived.

  The capacitor temperature increase calculation unit 2122 receives the capacitor loss Pc0, and calculates and outputs the temperature increase caused by the capacitor loss Pc0. When the capacitor loss Pc0 occurs, the temperature rises according to a curve of a certain time constant, so that the temperature rise calculation unit 2122 is realized by a low-pass filter calculation that simulates the temperature rise.

  By adding the reference temperature to the output value of the capacitor temperature rise calculation unit 2122 by the addition unit ad, the capacitor temperature TmpC is estimated by calculation.

  In the control unit 20 of the first embodiment, the torque limit value calculation unit 201 calculates the torque limit value Trq_max using the detected temperatures of the temperature sensors SnsTL and SnsTC. However, in the control unit 21 of the second embodiment, the reactor 21 The torque limit value Trq_max is calculated using the temperatures estimated by the temperature calculation unit 211 and the capacitor temperature calculation unit 212.

  Thus, in the second embodiment, the reactor temperature TmpL and the capacitor temperature TmpC can be derived from the current IL, and the same effect as in the first embodiment can be obtained.

  Further, in the second embodiment, the reactor temperature TmpL and the capacitor temperature TmpC are estimated using the reactor DC current IL. However, since the reactor DC current IL and the current I1 are equal, the current I1 is equal to the current I1. The temperature TmpL and TmpC can be similarly estimated and calculated using a current sensor for detecting the current I1 and using the current I1. In this case, for example, the direct current IL is obtained from the average value of the current I1, and thereafter the estimation calculation is similarly performed.

  Further, since the following relationship is established, the current IL can be derived from the torque Trq, the angular velocity ωm, and the voltage V1 of the electric rotating machine.

    V1 × IL × ηmg × ηinv × ηdcdc = Trq × ωm (9)

  Therefore, the current IL can be derived from the torque of the electric rotating machine MG and the output of the inverter without the current sensor SnsIL. Therefore, the reactor temperature TmpL and the capacitor temperature TmpC can be estimated and calculated from the torque of the electric rotating machine MG and the output of the inverter. That is, in the above equation (9), the torque Trq of the electric rotating machine is obtained from the outside as the torque of the electric rotating machine MG and the output of the inverter, ωm is obtained from the angular velocity calculation unit 205, and ηmg, ηinv, ηdcdc are stored in advance in the storage unit Keep a record.

  In addition, this invention is not limited to said each embodiment, These possible combinations, various design changes, etc. are included.

  For example, a small and lightweight circuit component having a small current / power rating is not limited to both a reactor and a capacitor, and may be at least one of a reactor and a capacitor. In that case, the current limit value calculation unit 2011 of the torque limit value calculation unit 201 in FIGS. 5 and 7 may obtain the current limit value I1max from the temperature of the circuit component as a target.

10 DC / DC converter,
11 Inverter,
20 control unit,
201 torque limit value calculation unit,
202 torque limiter,
203 torque control unit,
204 voltage controller,
205 angular velocity calculation unit,
211 Reactor temperature calculator,
212 capacitor temperature calculator,
2011 current limit value calculation unit,
2012 power limit calculation unit,
2013 limit torque calculation unit,
2031 current calculation unit,
2032 current control unit,
2033 dq axis current calculation unit,
2034 3φ voltage calculation unit,
2111 DC copper loss calculation unit,
2112 AC copper loss calculation unit,
2113 iron loss calculation unit,
2114 Reactor temperature rise calculation unit,
2115 Reactor temperature rise calculation unit,
2121 capacitor loss calculation unit,
2122 capacitor temperature rise calculation unit,
ad adder,
B battery,
CT, LT limit value calculation unit,
MIN limit value determination unit,
MG electric rotating machine,
S1a, S1b, S2a, S2b semiconductor switching element,
Sul, Suh, Svl, Svh, Swl, Swh Semiconductor switching element,
SU1, SU2 switching unit,
C0, C1, C2 (smooth) capacitors,
L reactor,
SnsV1, SnsV2 voltage sensor,
SnsIu, SnsIv, SnsIw 3-phase current sensor,
SnsTL current sensor,
Snsθm rotation angle sensor,
TmpL, TmpC temperature sensor,
VH, VL, VN, VM voltage terminals,
Vu, Vv, Vw 3-phase output terminal,
Gate1a, Gate1b, Gate2a, Gate2b gate signals,
Gateul, Gateuh, Gatevl, Gatevh, Gatel, Gatewh Inverter gate signal.

Claims (14)

A DC / DC converter including a first semiconductor switching element group that performs a switching operation, a reactor, and a capacitor;
An inverter that converts the output of the DC / DC converter into an alternating current by switching of the second semiconductor switching element group and supplies the alternating current to the electric rotating machine;
The DC / DC converter and the inverter are controlled, and the output of the inverter or the torque output of the electric rotating machine connected to the inverter is limited according to the temperature of the reactor of the DC / DC converter and the DC voltage to be boosted. A control unit for limiting the current converted by the DC / DC converter,
With
In the DC / DC converter,
The first semiconductor switching element group includes two switching units each composed of two semiconductor switching elements that perform complementary switching operations, and the semiconductor switching elements of the switching units are all connected in series. ,
One semiconductor switching element of each switching unit is connected in series to one side of the central voltage terminal, and the other semiconductor switching element of each switching unit is connected in series to the other side of the central voltage terminal. ,
The capacitor is connected between a connection point between semiconductor switching elements on one side of the central voltage terminal and a connection point between semiconductor switching elements on the other side, and between the central voltage terminal and the power supply side. Are connected in series,
The capacitor and the reactor are composed of an energy transfer capacitor that is charged and discharged by a switching operation of each semiconductor switching element of each switching unit and a reactor that accumulates electric energy for voltage conversion.
Power conversion device. A DC / DC converter including a first semiconductor switching element group that performs a switching operation, a reactor, and a capacitor;
An inverter that converts the output of the DC / DC converter into an alternating current by switching of the second semiconductor switching element group and supplies the alternating current to the electric rotating machine;
The DC / DC converter and the inverter are controlled, and the output of the inverter or the torque output of the electric rotating machine connected to the inverter is limited according to the temperature of the capacitor of the DC / DC converter and the DC voltage to be boosted. A control unit for limiting the current converted by the DC / DC converter,
With
In the DC / DC converter,
The first semiconductor switching element group includes two switching units each composed of two semiconductor switching elements that perform complementary switching operations, and the semiconductor switching elements of the switching units are all connected in series. ,
One semiconductor switching element of each switching unit is connected in series to one side of the central voltage terminal, and the other semiconductor switching element of each switching unit is connected in series to the other side of the central voltage terminal. ,
The capacitor is connected between a connection point between semiconductor switching elements on one side of the central voltage terminal and a connection point between semiconductor switching elements on the other side, and between the central voltage terminal and the power supply side. Are connected in series,
The capacitor and the reactor are composed of an energy transfer capacitor that is charged and discharged by a switching operation of each semiconductor switching element of each switching unit and a reactor that accumulates electric energy for voltage conversion.
Power conversion device. A DC / DC converter including a first semiconductor switching element group that performs a switching operation, a reactor, and a capacitor;
An inverter that converts the output of the DC / DC converter into an alternating current by switching of the second semiconductor switching element group and supplies the alternating current to the electric rotating machine;
The DC / DC converter and the inverter are controlled, and the output of the inverter or the torque of the electric rotating machine connected to the inverter is controlled according to the temperature of the reactor and the capacitor of the DC / DC converter and the boosted DC voltage. A control unit that limits the current converted by the DC / DC converter by limiting the output;
With
In the DC / DC converter,
The first semiconductor switching element group includes two switching units each composed of two semiconductor switching elements that perform complementary switching operations, and the semiconductor switching elements of the switching units are all connected in series. ,
One semiconductor switching element of each switching unit is connected in series to one side of the central voltage terminal, and the other semiconductor switching element of each switching unit is connected in series to the other side of the central voltage terminal. ,
The capacitor is connected between a connection point between semiconductor switching elements on one side of the central voltage terminal and a connection point between semiconductor switching elements on the other side, and between the central voltage terminal and the power supply side. Are connected in series,
The capacitor and the reactor are composed of an energy transfer capacitor that is charged and discharged by a switching operation of each semiconductor switching element of each switching unit and a reactor that accumulates electric energy for voltage conversion.
Power conversion device.   The control unit derives a current limit value of a current converted by the DC / DC converter according to a temperature of the reactor of the DC / DC converter, and integrates the current limit value and the boosted DC voltage. The power conversion device according to claim 1, wherein a power limit value is derived and the output of the inverter or a torque output of an electric rotating machine connected to the inverter is limited to be equal to or less than the power limit value.   The control unit derives a current limit value of a current converted by the DC / DC converter according to a temperature of the capacitor of the DC / DC converter, and integrates the current limit value and the boosted DC voltage. The power conversion device according to claim 2, wherein a power limit value is derived and the output of the inverter or a torque output of an electric rotating machine connected to the inverter is limited to be equal to or less than the power limit value. The control unit is
Deriving a first current limit value of the current converted by the DC / DC converter according to the temperature of the reactor of the DC / DC converter;
Deriving a second current limit value of the current converted by the DC / DC converter according to the temperature of the capacitor;
The smaller one of the first and second current limit values is used as the current limit value of the current converted by the DC / DC converter, and the current limit value and the boosted DC voltage are integrated, thereby limiting the power. The power conversion device according to claim 3, wherein a value is derived, and the output of the inverter or a torque output of an electric rotating machine connected to the inverter is limited to be equal to or less than the power limit value.   The output of the inverter or the torque output of an electric rotating machine connected to the inverter is limited so as to limit the current converted by the DC / DC converter when the temperature of the reactor is equal to or higher than a threshold temperature. Item 7. The power conversion device according to any one of Items 1, 3, 4, and 6.   The output of the inverter or the torque output of an electric rotating machine connected to the inverter is limited so as to limit the current converted by the DC / DC converter when the temperature of the capacitor is equal to or higher than a threshold temperature. Item 7. The power conversion device according to any one of Items 2, 3, 5, and 6. A first current sensor for detecting a current obtained by removing the reactor ripple as a first DC current;
The control unit is
The first DC current is squared, and a value obtained by integrating a coefficient corresponding to the winding resistance of the reactor is derived as a reactor loss.
By calculating a low-pass filter for the reactor loss, calculating a temperature rise of the reactor, and adding a reference temperature, thereby having a reactor temperature calculation unit for calculating the temperature of the reactor,
The temperature of the reactor derived by calculation is used as the temperature of the reactor for limiting the output of the inverter or the torque output of an electric rotating machine connected to the inverter. The power converter device according to any one of the above. A first current sensor for detecting a current obtained by removing the reactor ripple as a first DC current;
The control unit is
Reactor DC copper loss is calculated by squaring the first DC current, integrating the coefficient corresponding to the winding resistance of the reactor,
Reactor AC copper loss and reactor iron loss are set such that the voltage ratio V2 / V1 between the boosted DC voltage and the boosted DC voltage (where V1 is the boosted DC voltage and V2 is the boosted DC voltage) is 2 or more. And dividing the arithmetic expression by less than 2 and calculating from the boosted DC voltage and the boosted DC voltage,
Reactor copper loss is calculated by adding the reactor DC copper loss and the reactor AC copper loss,
By calculating the reactor copper loss with a low pass filter, the temperature rise of the reactor due to the reactor copper loss is calculated,
By calculating the reactor iron loss with a low pass filter, the temperature rise of the reactor due to the reactor iron loss is calculated,
A temperature rise due to the reactor copper loss, a temperature rise due to the reactor iron loss, and a reactor temperature calculation unit that calculates the temperature of the reactor by adding a reference temperature,
The temperature of the reactor derived by calculation is used as the temperature of the reactor for limiting the output of the inverter or the torque output of an electric rotating machine connected to the inverter. The power converter device according to any one of the above. The phase difference of the gate signal of each switching unit of the first semiconductor switching element group is controlled to be 180 °,
When the voltage ratio V2 / V1 is 2 or more, the reactor ripple current ΔIL is calculated by the following equation (1):
When the voltage ratio V2 / V1 is less than 2, the reactor ripple current ΔIL is derived by calculating the reactor ripple current ΔIL using the following equation (2):
ΔIL = [{V1 · (V2-2 × V1)} / (V2 × L)] · (Ts / 2) (1)
ΔIL = {(2 × V1−V2) · (V2−V1)} / (V2 × L)} · (Ts / 2) (2)
L: Inductor value of the reactor Ts: Switching period The temperature of the reactor is calculated by deriving the reactor AC copper loss and the reactor iron loss of the reactor based on the ripple current ΔIL of the reactor. Item 11. The power conversion device according to Item 10. A first current sensor for detecting a current obtained by removing the reactor ripple as a first DC current;
The control unit is
The capacitor loss Pc0 is less than 2 when the voltage ratio V2 / V1 of the boosted DC voltage and the boosted DC voltage (where V1 is the boosted DC voltage and V2 is the boosted DC voltage) is 2 or more. The calculation formula is divided at the time of the calculation, from the boosted DC voltage and the boosted DC voltage, the first DC current,
A capacitor temperature calculation unit for calculating the temperature of the capacitor by adding a reference temperature to a temperature rise obtained by low-pass filter calculation of the capacitor loss Pc0;
The temperature of the capacitor derived by calculation is used as the temperature of the capacitor for limiting the output of the inverter or the torque output of an electric rotating machine connected to the inverter. The power converter device according to any one of the above. The phase difference of the gate signal of each switching unit of the first semiconductor switching element group is controlled to be 180 °,
When the voltage ratio V2 / V1 is 2 or more, the current Ic0 of the capacitor is calculated by the following formulas (3) and (1):
When the voltage ratio V2 / V1 is less than 2, the current Ic0 of the capacitor is calculated by the following formulas (4) and (2):
Deriving the current Ic0 of the capacitor,
_{I c0 = √ [2 × (} V1 / V2) × {IL 2 + (ΔIL 2/12)}] (3)
_{I c0 = √ [2 × (} 1-V1 / V2) × {{IL 2 + (ΔIL 2/12)}] (4)
IL: the first DC current ΔIL: the ripple current of the reactor ΔIL = [{V1 · (V2-2 × V1)} / (V2 × L)] · (Ts / 2) (1)
ΔIL = {(2 × V1−V2) · (V2−V1)} / (V2 × L)} · (Ts / 2) (2)
L: inductance value of the reactor Ts: switching period The capacitor loss Pc0 is calculated by the following equation (5).
Pc0 = RC0 × Ic0 ² (5)
RC0: Resistance of the capacitor The power converter according to claim 12. The control unit is
Controlling the DC / DC converter by feeding back the boosted DC voltage;
Controlling the inverter to control the torque or current of the electric rotating machine;
The power converter according to any one of claims 1 to 13.

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