JP7091885B2 - Motor drive - Google Patents

Description

The present invention relates to an electric motor drive device including a plurality of inverter units that output a plurality of phases of alternating current power.

Conventionally, there is known an electric motor drive device including a plurality of inverter units that output a plurality of phases of AC power (see, for example, Patent Document 1).

Patent Document 1 discloses a multi-phase motor drive device including a plurality of single-phase pulse width modulation type inverters (hereinafter, referred to as "single-phase inverters") that output power of a plurality of phases of alternating current. Each single-phase inverter of this multi-phase motor drive unit is provided with a single-phase full bridge circuit connected to a DC power supply and a smoothing capacitor connected to the terminal on the DC power supply side of the single-phase full bridge circuit. There is. Then, each single-phase inverter converts the DC power from the DC power supply into AC power by the single-phase full bridge circuit and the smoothing capacitor, and outputs the AC power to the winding of the motor. It is configured. As a result, the multi-phase motor drive device is configured to output a plurality of phases of alternating current power to the motor.

Japanese Unexamined Patent Publication No. 2009-268277

すなわち、出力電力ｐの波形には、一般的に、振幅がＶＩの２分の１の大きさの脈動成分が重畳する。ここで、単相インバータのフルブリッジ回路にはエネルギー蓄積要素がないことから、単相インバータ内の損失を無視すれば、この出力電力ｐと、入力電力とは、等しくなるので、単相フルブリッジ回路に流入する直流電流ｉｄ１も、出力電力ｐと略相似の波形となる。なお、平滑コンデンサの電圧が一定ならば、完全に相似な波形となるが、実際には、この電圧は変動するため、完全な相似ではない。また、直流電流ｉｄ１は、単相インバータの入力端子から流入する電流ｉｄ１ａと平滑コンデンサＣ１から流れる電流ｉｃ１とを加えたものであり、以下の式（４）のように表せる。

ここで、単相インバータの直流入力端子のインピーダンスが、略０で、平滑コンデンサのインピーダンスより充分小さければ、上記の周波数２ωの電流成分は、平滑コンデンサにはほとんど流れず、この直流入力端子間で打ち消される。すなわち、周波数２ωの電流成分のほとんどは、電流ｉｄ１ａに流れる。しかしながら、大容量機では、直流入力端子間のインピーダンスが無視できない程度に大きくなるので、平滑コンデンサに分流する周波数２ωの電流が比較的大きくなる。ここで、上記特許文献１に記載されているような、多巻線交流電動機を駆動するための電動機駆動装置は、大容量のものが多く、単相インバータ自体も大型化し、単相インバータの直流入力端子や直流電源の出力端子の間を接続する配線も長くなり、無視できないインピーダンスとなるため、平滑コンデンサに流れる周波数２ωの電流が比較的大きくなる。また、この平滑コンデンサには、単相インバータのＰＷＭ制御などに伴う大きな高調波のリプル電流が流れるため、この平滑コンデンサの温度上昇や寿命などに影響を及ぼす。ここで更に、上記のように、比較的大きな周波数２ωの電流（上記高調波の全リプル電流実効値の数十％にも及ぶ場合がある）が平滑コンデンサに流れるため、周波数２ωの電流（脈動成分）が平滑コンデンサの損失増加、寿命短縮や容量増加による大型化などに拍車をかけるという問題点があった。なお、単相インバータおよび電動機の巻線を複数群に分割した場合にも、各単相インバータの構成は上記と同様であるため、上記と同様の課題があった。 Here, in the polyphase electric motor drive device as described in Patent Document 1, in each single-phase inverter, the output power (the product of the fundamental wave output voltage and the fundamental wave output current) is the fundamental wave output voltage. The waveform oscillates at an angular frequency (2ω) that is twice the angular frequency. That is, assuming that the output power is p, the fundamental wave output voltage whose amplitude is V is v, the fundamental wave output current whose amplitude is I is i, the power factor is cosθ, the angular frequency is ω, and the time is t, the following Can be expressed as the equations (1) to (3) of.

That is, in general, a pulsating component having an amplitude of half that of VI is superimposed on the waveform of the output power p. Here, since the full-bridge circuit of the single-phase inverter has no energy storage element, if the loss in the single-phase inverter is ignored, the output power p and the input power are equal to each other, so that the single-phase full bridge The direct current id1 flowing into the circuit also has a waveform substantially similar to the output power p. If the voltage of the smoothing capacitor is constant, the waveforms are completely similar, but in reality, this voltage fluctuates, so the waveforms are not completely similar. Further, the direct current id1 is the sum of the current id1a flowing in from the input terminal of the single-phase inverter and the current ic1 flowing from the smoothing capacitor C1, and can be expressed by the following equation (4).

Here, if the impedance of the DC input terminal of the single-phase inverter is approximately 0 and is sufficiently smaller than the impedance of the smoothing capacitor, the current component of the frequency 2ω described above hardly flows through the smoothing capacitor, and the current component of the frequency 2ω hardly flows between the DC input terminals. It will be canceled. That is, most of the current components having a frequency of 2ω flow in the current id1a. However, in a large-capacity machine, the impedance between the DC input terminals becomes so large that it cannot be ignored, so that the current having a frequency of 2ω shunted to the smoothing capacitor becomes relatively large. Here, many of the motor drive devices for driving a multi-winding AC motor as described in Patent Document 1 have a large capacity, the single-phase inverter itself is also enlarged, and the direct current of the single-phase inverter is increased. The wiring connecting the input terminal and the output terminal of the DC power supply is also long, and the impedance is not negligible, so the current with a frequency of 2ω flowing through the smoothing capacitor becomes relatively large. Further, since a large harmonic ripple current due to PWM control of the single-phase inverter flows through this smoothing capacitor, it affects the temperature rise and the life of the smoothing capacitor. Here, further, as described above, a relatively large current with a frequency of 2ω (which may reach several tens of percent of the effective value of the total ripple current of the harmonics) flows through the smoothing capacitor, so that a current with a frequency of 2ω (pulsation). There is a problem that the component) accelerates the increase in the loss of the smoothing capacitor, the shortening of the life, and the increase in size due to the increase in capacity. Even when the windings of the single-phase inverter and the motor are divided into a plurality of groups, the configuration of each single-phase inverter is the same as the above, so that there is a problem similar to the above.

The present invention has been made to solve the above-mentioned problems, and one object of the present invention is to reduce the pulsating component flowing through the capacitor and to reduce the responsibility of the capacitor. It is to provide a motor drive device.

In order to achieve the above object, the motor drive device according to one aspect of the present invention converts the DC power input from the DC power source into AC power and is isolated from each other (n is 6 or more). A motor having windings of) is equipped with m (m is an integer of 3 or more) inverter units that output multi-phase AC power and a control unit, and each of the m inverter units is equipped with a control unit. , The first single-phase full bridge circuit connected to the first winding of the n windings, the second single-phase full bridge circuit connected to the second winding, and the first single-phase full. A common capacitor connected to the terminal on the DC power supply side of the bridge circuit and the second single-phase full bridge circuit is provided, and the control unit is output from the first single-phase full bridge circuit to the first winding. The pulsating component of the combined waveform in the common capacitor of the first power and the second power output from the second single-phase full bridge circuit to the second winding is either the first power or the second power. The first single-phase full bridge circuit and the second single-phase full bridge circuit are controlled so as to be equal to or less than the amplitude of the pulsating component.

ここで、Ｖは、第１基本波出力電圧および第２基本波出力電圧の振幅であり、Ｉは、第１基本波出力電流および第２基本波出力電流の振幅であり、ωは角周波数であり、ｔは時間である。そして、第１単相フルブリッジ回路から出力される第１電力ｐ１－１は以下の式（９）のように表すことができる。

式（９）によれば、第１電力ｐ１－１の波形には、それぞれ、角周波数２ωでかつＶＩの２分の１の振幅の脈動成分が含まれている。また、第２電力ｐ２－１の波形にも、同様に、角周波数２ωでかつＶＩの２分の１の振幅の脈動成分が含まれる。ここで、第１電力ｐ１－１と第２単相フルブリッジ回路から出力される第２電力ｐ２－１とを合成すると、式（１０）のように表すことができる。

この場合、合成した電力「（ｐ１－１）＋（ｐ２－１）」は、一定値ＶＩｃｏｓθに、角周波数２ωの脈動成分の波形が重畳する波形となる。ここで、第１単相フルブリッジ回路および第２単相フルブリッジ回路には、エネルギー蓄積要素がないことから、回路内の損失を無視すれば、第１単相フルブリッジ回路および第２単相フルブリッジ回路の出力電力「（ｐ１－１）＋（ｐ２－１）」と、入力電力とは等しくなる。ここで、第１単相フルブリッジ回路に流入する電流をｉｄ１－１とし、第２単相フルブリッジ回路に流入する電流をｉｄ２－１とする（図１参照）と、電流「（ｉｄ１－１）＋（ｉｄ２－１）」は、出力電力「（ｐ１－１）＋（ｐ２－１）」と略相似の波形となる。また、電流「（ｉｄ１－１）＋（ｉｄ２－１）」は、入力端子から流入する電流ｉｄ１ａと共通コンデンサから流れる電流ｉｃ１とを加えたものであり、以下の式（１１）のように表せる。

ここで、入力端子のインピーダンスが略０で、共通コンデンサのインピーダンスより充分小さければ，周波数２ωの脈動成分は、共通コンデンサにはほとんど流れず、この端子間で打ち消される。すなわち、２ωの脈動成分は、ほとんど電流ｉｄ１ａに流れる。しかし、大容量機では、端子間のインピーダンスが無視できない程度に大きくなるので、共通コンデンサに分流する周波数２ωの電流が比較的大きくなる。これに対して、本発明では、上記のように構成することにより、共通コンデンサにおける合成波形の脈動成分の振幅を、第１電力または第２電力のいずれか一方の脈動成分の振幅以下にすることができるので、コンデンサを第１単相フルブリッジ回路および第２単相フルブリッジ回路の各々に設ける場合と異なり、この電力脈動によって生じる共通コンデンサの責務増加を抑制することができる。この結果、共通コンデンサにおける損失増加、寿命短縮や容量増加を抑制することができる。 In the motor drive device according to one aspect of the present invention, as described above, the m inverter units have a first single-phase full bridge circuit, a second single-phase full bridge circuit, and a common capacitor (preferably a single capacitor), respectively. By providing one common capacitor), the number of parts can be reduced as compared with the case where two or more sets of m inverter units equipped with a single single-phase full bridge circuit and a smoothing capacitor are provided. Then, the amplitude of the pulsating component of the combined waveform in the common capacitor of the first power and the second power can be made equal to or less than the amplitude of the pulsating component of either the first power or the second power. Here, in the first inverter unit among the m inverter units, the output voltage of the first fundamental wave output from the first single-phase full bridge circuit to the first winding is va1-1 and the first fundamental wave. The output current is ia1-1, the second fundamental wave output voltage output from the second single-phase full bridge circuit to the second winding is va2-1, and the second fundamental wave output current is ia2-1. Assuming that the force factor is cosθ and the phase difference between the first fundamental wave output voltage va1-1 and the second fundamental wave output voltage va2-1 is α, it can be expressed as the following equations (5) to (8). .. In the following equation, harmonics are described as being ignored. In the following description, the operation and effect of the first inverter unit will be described, but the second to mth inverter units also have the same operation and effect as the first inverter unit.

Here, V is the amplitude of the first fundamental wave output voltage and the second fundamental wave output voltage, I is the amplitude of the first fundamental wave output current and the second fundamental wave output current, and ω is the angular frequency. Yes, t is the time. The first power p1-1 output from the first single-phase full bridge circuit can be expressed by the following equation (9).

According to the equation (9), each waveform of the first power p1-1 contains a pulsating component having an angular frequency of 2ω and an amplitude of 1/2 of VI. Further, the waveform of the second power p2-1 also contains a pulsating component having an angular frequency of 2ω and an amplitude of 1/2 of VI. Here, when the first power p1-1 and the second power p2-1 output from the second single-phase full bridge circuit are combined, it can be expressed as the equation (10).

In this case, the combined power “(p1-1) + (p2-1)” is a waveform in which the waveform of the pulsating component having an angular frequency of 2ω is superimposed on the constant value VIcosθ. Here, since the first single-phase full bridge circuit and the second single-phase full bridge circuit do not have an energy storage element, the first single-phase full bridge circuit and the second single-phase can be ignored if the loss in the circuit is ignored. The output power "(p1-1) + (p2-1)" of the full bridge circuit is equal to the input power. Here, when the current flowing into the first single-phase full bridge circuit is set to id1-1 and the current flowing into the second single-phase full bridge circuit is set to id2-1 (see FIG. 1), the current "(id1-1)". ) + (Id2-1) ”has a waveform substantially similar to the output power“ (p1-1) ＋ (p2-1) ”. Further, the current "(id1-1) + (id2-1)" is the sum of the current id1a flowing from the input terminal and the current ic1 flowing from the common capacitor, and can be expressed by the following equation (11). ..

Here, if the impedance of the input terminal is substantially 0 and is sufficiently smaller than the impedance of the common capacitor, the pulsating component having a frequency of 2ω hardly flows to the common capacitor and is canceled between the terminals. That is, most of the pulsating component of 2ω flows in the current id1a. However, in a large-capacity machine, the impedance between the terminals becomes so large that it cannot be ignored, so that the current having a frequency of 2ω shunted to the common capacitor becomes relatively large. On the other hand, in the present invention, the amplitude of the pulsating component of the synthetic waveform in the common capacitor is set to be equal to or less than the amplitude of the pulsating component of either the first power or the second power by configuring as described above. Therefore, unlike the case where the capacitor is provided in each of the first single-phase full bridge circuit and the second single-phase full bridge circuit, it is possible to suppress the increase in the duty of the common capacitor caused by this power pulsation. As a result, it is possible to suppress an increase in loss, shortening of life, and increase in capacity of the common capacitor.

式（１３）によると、合成した電力「（ｐ１－１）＋（ｐ２－１）」の脈動成分の振幅ＶＩｃｏｓα（最大値がＶＩの２分の１）が、式（９）に示す第１電力ｐ１－１のみの脈動成分の振幅（ＶＩの２分の１）以下または第２電力ｐ２－１のみの脈動成分の振幅以下になる。すなわち、制御部により、同一のインバータユニット内において、第１基本波出力電圧の位相と第２基本波出力電圧の位相との位相差（α）が、６０度以上１２０度以下となるように、第１単相フルブリッジ回路および第２単相フルブリッジ回路を制御すれば、脈動成分を、ＶＩの２分の１以下に抑制することができる。 In the motor drive device according to the above one aspect, preferably, the control unit has the phase of the first fundamental wave output voltage output from the first single-phase full bridge circuit to the first winding in the same inverter unit. , The first single-phase full bridge circuit so that the phase difference from the phase of the second fundamental wave output voltage output from the second single-phase full bridge circuit to the second winding is 60 degrees or more and 120 degrees or less. And controls the second single phase full bridge circuit. Here, the inventor of the present application has found the following configuration by paying attention to the content of the above formula (10). That is, the inventor of the present application has found that the following equations (12) and (13) hold for the pulsating component of the synthesized electric power "(p1-1) + (p2-1)".

According to the equation (13), the amplitude VIcosα (maximum value is half of VI) of the pulsating component of the combined electric power “(p1-1) + (p2-1)” is the first expressed in the equation (9). The amplitude of the pulsating component of the power p1-1 only (half of VI) or less or the amplitude of the pulsating component of the second power p2-1 only. That is, the control unit ensures that the phase difference (α) between the phase of the first fundamental wave output voltage and the phase of the second fundamental wave output voltage is 60 degrees or more and 120 degrees or less in the same inverter unit. By controlling the first single-phase full bridge circuit and the second single-phase full bridge circuit, the pulsation component can be suppressed to less than half of the VI.

上記一の局面による電動機駆動装置において、好ましくは、制御部は、第１基本波出力電圧の位相と第２基本波出力電圧の位相との位相差が、ｎ個の巻線に出力される基本波出力電圧同士の位相差のうちの最も９０度に近い位相差に対応する状態となるように、第１単相フルブリッジ回路および第２単相フルブリッジ回路を制御する。このように構成すれば、同一のインバータユニットにおいて、第１基本波出力電圧の位相と第２基本波出力電圧の位相との位相差が略９０度となるように、第１単相フルブリッジ回路と第２単相フルブリッジ回路とを制御することができる。この結果、共通コンデンサに流れる脈動成分の振幅をより一層低減することができるので、共通コンデンサの責務を低減することができる。また、共通コンデンサに流れる脈動成分の振幅をより一層低減することができることにより、共通コンデンサの温度上昇を抑制することができ、共通コンデンサの長寿命化を図ることができる。そして、共通コンデンサに流れる脈動成分の振幅をより一層低減することができるので、共通コンデンサの容量を小さくすることができ、共通コンデンサをより一層小型化することができる。 Further, when the phase difference α is 90 degrees, cosα can be set to 0 as shown in the following equation (14). Therefore, by setting α to the value closest to 90 degrees, the amplitude of the pulsating component can be increased. It can be reduced to a value close to 0.

In the motor drive device according to the above one aspect, preferably, the control unit outputs the phase difference between the phase of the first fundamental wave output voltage and the phase of the second fundamental wave output voltage to n windings. The first single-phase full bridge circuit and the second single-phase full bridge circuit are controlled so as to correspond to the phase difference closest to 90 degrees among the phase differences between the wave output voltages. With this configuration, in the same inverter unit, the first single-phase full bridge circuit so that the phase difference between the phase of the first fundamental wave output voltage and the phase of the second fundamental wave output voltage is approximately 90 degrees. And the second single-phase full bridge circuit can be controlled. As a result, the amplitude of the pulsating component flowing through the common capacitor can be further reduced, so that the responsibility of the common capacitor can be reduced. Further, since the amplitude of the pulsating component flowing through the common capacitor can be further reduced, the temperature rise of the common capacitor can be suppressed, and the life of the common capacitor can be extended. Since the amplitude of the pulsating component flowing through the common capacitor can be further reduced, the capacity of the common capacitor can be further reduced, and the common capacitor can be further miniaturized.

In this case, preferably, m is a half of n, and the control unit has m first voltage vectors output from m inverter units and is a voltage vector of m first fundamental wave output voltages. N fundamental wave output voltage vectors having different phases by predetermined angles, including the second voltage vector which is the voltage vector of the m second fundamental wave output voltage output from the inverter unit of the above. It controls the first single-phase full bridge circuit and the second single-phase full bridge circuit. With this configuration, when driving an electric motor to which n-phase (n is an even number) electric power is supplied, the amplitude of the pulsating component of the electric power output from all the inverter units is reduced in order to drive the electric motor. Therefore, it is possible to suppress an increase in loss, shortening of life, and increase in capacity in all common capacitors arranged in the motor drive device.

In the electric motor drive device that controls the phase difference so as to have a phase difference close to 90 degrees, preferably m is half of n and an odd number, and the control unit is m output from m inverter units. The first fundamental wave output voltage vector group consisting of the first voltage vector which is the voltage vector of the first fundamental wave output voltage is formed, and the m second fundamental wave outputs output from the m inverter units are output. The first single-phase full bridge circuit and the second single-phase full bridge circuit are controlled so as to form a second fundamental wave output voltage vector group consisting of a second voltage vector which is a voltage vector of voltage. With this configuration, even when driving an electric motor to which odd-numbered m-phase power is supplied, one of the odd-numbered m first single-phase full-bridge circuits and the odd-numbered m-phase can be driven. One second single-phase full bridge circuit can be provided in the same inverter unit and driven. As a result, even when driving an electric motor to which an odd number of m-phase electric power is supplied, the amplitude of the pulsating component of the electric power output from all the inverter units can be reduced because the electric motor is driven, so that the electric motor can be driven. In all the common capacitors arranged in the drive device, it is possible to suppress an increase in loss, a shortening of life, and an increase in capacity.

In the motor drive device according to the above one aspect, preferably, each of the m inverter units is provided with a single common capacitor. With this configuration, the number of parts can be reduced as compared with the case where a plurality of common capacitors are provided.

In the electric motor drive device according to the above one aspect, preferably, the first single-phase full bridge circuit and the second single-phase full bridge circuit have a switching element and a diode connected to the switching element in antiparallel, respectively. The common capacitor is connected to both the positive and negative terminals of the first single-phase full bridge circuit and both the positive and negative terminals of the second single-phase full bridge circuit. With this configuration, the pulsating component of the combined waveform in the common capacitor of the first power and the second power is equal to or less than the amplitude of the pulsating component of either the first power or the second power. The first single-phase full-bridge circuit can be easily connected to the winding of, and the second single-phase full-bridge circuit can be easily connected to the second winding.

In this case, preferably at least one of the switching element and the diode contains silicon carbide. With this configuration, it is possible to reduce the power loss as compared with the case where both the switching element and the diode are configured by the element composed of silicon. As a result, the cooling mechanism portion of the first single-phase full bridge circuit and the second single-phase full bridge circuit can be miniaturized, so that the first single-phase full bridge circuit and the second single-phase full bridge circuit are the same inverter. It can be easily placed in a unit (easily configured as a single unit).

According to the present invention, as described above, the pulsating component flowing through the capacitor can be reduced, and the duty of the capacitor can be reduced.

It is a circuit diagram which shows the structure of the motor drive device by 1st Embodiment of this invention. It is a figure for demonstrating the fundamental wave output voltage (voltage vector) by 1st Embodiment of this invention. It is a figure for demonstrating the fundamental wave output voltage vector of each inverter unit according to 1st Embodiment of this invention. It is a figure which shows the waveform of the fundamental wave output voltage and the waveform of the fundamental wave output current in the 1st inverter unit by 1st Embodiment of this invention. It is a figure for demonstrating the combined waveform (composite waveform) of the 1st electric power and the 2nd electric power according to 1st Embodiment of this invention. It is a circuit diagram which shows the structure of the motor drive device by 2nd Embodiment of this invention. It is a figure for demonstrating the fundamental wave output voltage (voltage vector) in the 1st single phase full bridge circuit by 2nd Embodiment of this invention. It is a figure for demonstrating the fundamental wave output voltage (voltage vector) in the 2nd single phase full bridge circuit by 2nd Embodiment of this invention. It is a figure for demonstrating the fundamental wave output voltage vector of each inverter unit according to 2nd Embodiment of this invention. It is a figure which shows the combined waveform (composite waveform) of the 1st electric power and the 2nd electric power by the 2nd Embodiment of this invention. It is a circuit diagram which shows the structure of the electric motor drive device by the modification of 1st and 2nd Embodiment of this invention.

Hereinafter, embodiments embodying the present invention will be described with reference to the drawings.

[First Embodiment]
(Composition of motor drive device)
The configuration of the motor drive device 100 according to the first embodiment will be described with reference to FIGS. 1 to 5.

As shown in FIG. 1, the motor drive device 100 converts the DC power from the DC power supply 101 into a multi-phase (n-phase: n is an integer of 3 or more) AC power, and also converts the multi-phase AC power. It is configured to output electric power to the motor 102 (load). The DC power supply 101 is preferably configured as a single DC power supply device.

The electric motor 102 is preferably configured as a multi-phase (multi-phase) winding AC motor (motor). For example, the electric motor 102 is configured as a motor for rotating a propeller for propelling a ship. Specifically, the motor 102 is provided with n windings 120 that are insulated from each other. The n windings 120 include a plurality of first windings 121 and a plurality of second windings 122. The plurality of first windings 121 are insulated from each other, and m pieces (m is an integer of 3 or more) are provided. The plurality of second windings 122 are isolated from each other, and m pieces (m is an integer of 3 or more) are provided. Here, m is half of n. Then, AC power of different phases is supplied to each of the m first windings 121. Further, AC power of different phases is supplied to each of the m second windings 122. That is, the electric motor 102 is configured as an n-phase motor.

The motor drive device 100 includes m inverter units 1 that output a plurality of phases of alternating current power to the motor 102. In addition, in FIG. 1, the m inverter units 1 are sequentially illustrated by assigning reference numerals “U1”, “U2”, ..., “Um” to distinguish them from each other. Further, each inverter unit 1 and the electric motor 102 are connected by, for example, wiring 103 (reference numerals W11, W12, ..., W1m, W21, W22, ..., W2m). Specifically, the first (U1) inverter unit 1 and the electric motor 102 are connected via wiring 103 (W11 and W21). Further, the m (Um) inverter unit 1 and the electric motor 102 are connected to each other via wiring 103 (W1m and W2m).

The m inverter units 1 have a first single-phase full bridge circuit 10 connected to the first winding 121, a second single-phase full bridge circuit 20 connected to the second winding 122, and a second, respectively. 1 Connected to the power supply side positive terminal 11 on the DC power supply 101 side of the single-phase full bridge circuit 10 and the power supply side negative terminal 12, and the power supply side positive terminal 21 on the DC power supply 101 side of the second single-phase full bridge circuit 20. A common capacitor 30 connected to the power supply side negative terminal terminal 22 and a housing 40 are provided. For example, the first single-phase full bridge circuit 10, the second single-phase full bridge circuit 20, and the common capacitor 30 are arranged (mounted) in a common housing 40. Further, the positive electrode terminals P (P1, P2, ..., Pm) of the DC power supply 101 and the negative electrode terminals N (N1, N2, ..., Nm) are the first single-phase full bridge circuit 10 and the second. Each is connected to the single-phase full bridge circuit 20. Further, the current input from the DC power supply 101 to the positive electrode terminal P1 is defined as id1a. Further, the current flowing into the first single-phase full bridge circuit 10 is set to id1-1, and the current flowing into the second single-phase full bridge circuit 20 is set to id2-1. Further, assuming that the current flowing from the common capacitor 30 is ic1, the above equation (11) holds. It should be noted that not only the first inverter unit 1 but also the second to mth inverter units 1 have the same relationship as the above equation (11).

Each of the first single-phase full bridge circuits 10 of the m inverter units 1 has voltages va1-1, va1-2, ..., Va1-m (hereinafter, referred to as "voltage va1" unless otherwise specified). Each second single-phase full bridge circuit 20 outputs voltages va2-1, va2-2, ..., Va2-m (hereinafter, referred to as "voltage va2" unless otherwise specified). Hereinafter, the first (U1) inverter unit 1 of the m inverter units 1 will be described, but the second (U2) to m (Um) inverter units 1 are the same as the first inverter unit 1. Since it is configured in, the description is omitted. The voltage va1 is an example of the "first fundamental wave output voltage" in the claims, and the voltage va2 is an example of the "second fundamental wave output voltage" in the claims.

Here, in the first embodiment, the motor drive device 100 is configured with m = 6 and n = 12. That is, the motor drive device 100 is configured to output 12-phase alternating current power. Further, the motor 102 is configured as a 12-phase AC motor.

The first single-phase full bridge circuit 10 and the second single-phase full bridge circuit 20 are respectively configured as circuits that perform single-phase inverter operation. Specifically, in the first single-phase full bridge circuit 10, a full bridge circuit is provided by a plurality of (for example, four) switching elements 13 and diodes 14 connected in antiparallel to each of the plurality of switching elements 13. Is configured. Similarly to the first single-phase full-bridge circuit 10, the second single-phase full-bridge circuit 20 also comprises a full-bridge circuit including a switching element 23 and a diode 24.

Here, in the first embodiment, at least one of the switching elements 13 and 23 and the diodes 14 and 24, preferably both, contains silicon carbide (SiC). The switching elements 13 and 23 are configured as, for example, a field effect type semiconductor element (SiC-PWM) containing silicon carbide. Diodes 14 and 24 are, for example, freewheel diodes (SiC-FWD) containing silicon carbide.

The output side terminals 15a and 15b of the first single-phase full bridge circuit 10 are connected to the corresponding first winding 121 via wiring 103 (reference numeral W11). The first single-phase full bridge circuit 10 outputs the voltage va1-1. As a result, the fundamental wave output current ia1-1 (hereinafter referred to as "current ia1-1") flows through the first winding 121. At this time, the power output from the first single-phase full bridge circuit 10 is defined as the first power p1-1.

Further, the output side terminals 25a and 25b of the second single-phase full bridge circuit 20 are connected to the corresponding second winding 122 via the wiring 103 (reference numeral W21). The second single-phase full bridge circuit 20 outputs the voltage va2-1. As a result, the fundamental wave output current ia2-1 (hereinafter referred to as “current ia2-1”) flows through the second winding 122. At this time, the power output from the second single-phase full bridge circuit 20 is defined as the second power p2-1.

The motor drive device 100 is provided with a control unit 50. The control unit 50 controls signals (gate drive signals) to each switching element 13 provided in the first single-phase full bridge circuit 10 and each switching element 23 provided in the second single-phase full bridge circuit 20. Is configured to drive (turn on / off) each switching element 13 and each switching element 23 by transmitting the above.

Further, the power supply side positive electrode terminal 11 of the first single-phase full bridge circuit 10 and the power supply side positive electrode terminal 21 of the second single-phase full bridge circuit 20 are connected to the positive electrode terminal P (P1) of the DC power supply 101. .. Further, the power supply side negative electrode terminal 12 of the first single-phase full bridge circuit 10 and the power supply side negative electrode terminal 22 of the second single-phase full bridge circuit 20 are connected to the negative electrode terminal N (N1) of the DC power supply 101. ..

Here, in the first embodiment, the common capacitor 30 is configured as, for example, a single capacitor C1. Specifically, the common capacitor 30 is arranged between the DC power supply 101 and the first single-phase full bridge circuit 10 and the second single-phase full bridge circuit 20, and is a smoothing capacitor (DC capacitor) in the inverter unit 1. ) Functions. Specifically, the positive electrode terminal 31 of the common capacitor 30 includes the power supply side positive electrode terminal 11 of the first single-phase full bridge circuit 10, the power supply side positive electrode terminal 21 of the second single-phase full bridge circuit 20, and the positive electrode terminal P (P1). )It is connected to the. Further, the negative electrode terminal 32 of the common capacitor 30 is connected to the power supply side negative electrode terminal 12 of the first single-phase full bridge circuit 10 and the power supply side negative electrode terminal 22 of the second single-phase full bridge circuit 20 and the negative electrode terminal N (N1). Has been done.

(Structure of control unit)
The control unit 50 is composed of, for example, a central processing unit (CPU: Central Processing Unit), and is a voltage va1-1 output from each first single-phase full bridge circuit 10 of m inverter units 1 based on a control program. , Va1-2, ..., va1-m and the amplitude, frequency and phase of the voltages va2-1, va2-2, ..., va2-m output from each second single-phase full bridge circuit 20. It is configured to do. Further, the control unit 50 is provided with a gate drive circuit, and the gate drive circuit is configured to transmit a gate drive signal to each switching element 13 and each switching element 23.

Here, in the first embodiment, the control unit 50 receives the electric power p1-1 output to the first winding 121 and the electric power output to the second winding 122 in the first (U1) inverter unit 1. First, the amplitude of the pulsating component of the combined waveform in the common capacitor 30 with p2-1 is less than half of the amplitude VI of the pulsating component of either the power p1-1 or the power p2-1. It is configured to control the single-phase full bridge circuit 10 and the second single-phase full bridge circuit 20.

Specifically, in the first inverter unit 1, the second single-phase full bridge circuit 20 has a phase difference of 60 degrees or more and 120 degrees from the first winding 121 to which the first single-phase full bridge circuit 10 is connected. It is connected to the following second winding 122. The second single-phase full bridge circuit 20 has a phase difference of 60 degrees or more and 120 degrees or less with respect to the first voltage va1-1 output by the first single-phase full bridge circuit 10 to the first winding 121. The second voltage v2-1 is output.

Preferably, in the first embodiment, in the same inverter unit 1, the first single-phase full bridge circuit 10 is connected to the first winding 121, and as shown in FIG. 2, the second single-phase full bridge circuit 20 is connected to the second winding 122, which has a phase difference closest to 90 degrees with the first winding 121. Therefore, the second single-phase full bridge circuit 20 outputs the second voltage va2, which has a phase difference closest to 90 degrees with respect to the phase of the first voltage va1 output by the first single-phase full bridge circuit 10.

That is, in the same inverter unit 1, the control unit 50 has a phase difference between the phase of the first voltage va1 and the phase of the second voltage va2 of 60 degrees or more and 120 degrees or less (preferably about 90 degrees). As described above, it is configured to control the first single-phase full bridge circuit 10 and the second single-phase full bridge circuit 20.

Specifically, as shown in FIG. 2, the control unit 50 has a voltage va1-1, which is output from the first single-phase full bridge circuit 10 of the m inverter units 1 to the first winding 121 of the m pieces. While controlling va1-2, ..., Va1-m, the voltages va2-1 and va2 output from the second single-phase full bridge circuit 20 of the m inverter units 1 to the second winding 122 of the m pieces. -2, ..., It is configured to control v2-m.

That is, the control unit 50 is output from the m inverter units 1 to the windings of the n-phase (12-phase) of the electric motor 102, and the fundamental wave output voltage vectors vb1, vb2, ..., Vbn (12) ( Hereinafter, the output voltage of each inverter unit 1 is controlled so that the "voltage vector vb") is output at equal angular intervals (with the same phase difference in the fundamental wave output voltage). Specifically, the control unit 50 of each first single-phase full bridge circuit 10 and each second single-phase full bridge circuit 20 so that the phase difference between the voltage vectors vb is deviated by an angle obtained by dividing 360 degrees by n. It is configured to control the output voltage. The angle obtained by dividing 360 degrees by n is an example of the "predetermined angle" in the claims. Further, the voltage vector vbx (x is an odd number) is an example of the "first voltage vector" in the claims. Further, the voltage vector vby (y is an even number) is an example of the "second voltage vector" in the claims.

As shown in FIG. 2, when m = 6, the control unit 50 shifts the phases of the voltages va1-1, va1-2, and va1-3 by 30 degrees in order, and the voltage va1-4, Each first single-phase full bridge circuit 10 so that the phases of va1-5 and va1-6 are shifted by 30 degrees in order, and the phase difference between the voltage va1-1 and the voltage va1-4 is 180 degrees. Is configured to control. Further, the control unit 50 arranges that the phases of the voltages va2-1, va2-2, and va2-3 are sequentially shifted by 30 degrees, and the phases of the voltages va2-4, va2-5, and va2-6. Is configured to control each second single-phase full bridge circuit 20 so that the voltage is shifted by 30 degrees in order and the phase difference between the voltage va2-1 and the voltage va2-4 is 180 degrees.

For example, in the example of FIG. 2, in the first inverter unit 1, the first single-phase full bridge circuit 10 is connected to the first winding 121, and the second single-phase full bridge circuit 20 is the first winding 121. It is connected to the second winding 122 which has a phase difference of 90 degrees. In this case, the phase of the voltage va1-1 (voltage vector vb1) output by the first single-phase full bridge circuit 10 and the phase of the voltage va2-1 (voltage vector vb4) output by the second single-phase full bridge circuit 20. The phase difference is 90 degrees. In the second inverter units 1 to 6, as in the first inverter unit 1, the phase of the voltage va1-2 to 1-6 output by the first single-phase full bridge circuit 10 and the second phase. The phase difference from the phase of the voltage va2-2 to 2-6 output by the single-phase full bridge circuit 20 is 90 degrees, respectively.

As a result, as shown in FIG. 4, the phase of the waveform (sine wave) of the voltage va1-1 and the phase of the waveform (sine wave) of the voltage va2-1 have a phase difference of 90 degrees (= π / 2). Will be. The phase of the waveform (sine wave) of the current ia1-1 and the phase of the waveform (sine wave) of the current ia2-1 have a phase difference of 90 degrees (= π / 2). Note that FIG. 4 shows an example in which the power factor is cos θ = 0.8. When the amplitude of the voltage va1-1 and the amplitude of the waveform of the voltage va2-1 are V, and the amplitude of the current ia1-1 and the current ia2-1 are I, the waveform of the power p1-1 is as follows. It is represented by the formula (15), and the waveform of the power p2-1 is represented by the following formula (16).

In this case, as shown in FIG. 5, the waveform of the electric power (p1-1 + p2-1) in which the electric power p1-1 and the electric power p2-1 are combined becomes 0.8VI, which is a constant value. That is, the electric power (p1-1 + p2-1) is expressed by the following equation (17).

As a result, in the first embodiment, in the first inverter unit 1, the pulsating component of the electric power (p1-1 + p2-1) becomes substantially 0 (0 when the harmonic component and the like are ignored). Therefore, in the first inverter unit 1, the pulsating component of the current flowing through the common capacitor 30 is reduced. Further, in the second (U2) to sixth (U6) inverter units 1, the pulsating component of the current flowing through the common capacitor 30 is reduced as in the first inverter unit 1.

[Effect of the first embodiment]
In the first embodiment, the following effects can be obtained.

In the first embodiment, as described above, the m inverter units 1 are provided with a first single-phase full bridge circuit 10, a second single-phase full bridge circuit 20, and a single common capacitor 30, respectively. As a result, the number of parts can be reduced as compared with the case where two sets of m inverter units equipped with a single-phase full bridge circuit and a smoothing capacitor are provided.

Further, in the first embodiment, as described above, in the same inverter unit 1, the phase difference between the first voltage va1 and the second voltage va2 is 60 degrees or more and 120 degrees or less. It is configured to control the first single-phase full bridge circuit 10 and the second single-phase full bridge circuit 20. As a result, the amplitude of the pulsating component of the current flowing through the common capacitor 30 can be suppressed to less than half of the amplitude when only one single-phase full bridge circuit is connected to the capacitor. As a result, the pulsating component flowing through the common capacitor 30 can be reduced, and the responsibility of the common capacitor 30 can be reduced.

Further, in the first embodiment, as described above, in the control unit 50, the phase difference between the first voltage va1 and the second voltage va2 is close to 90 degrees among the phase differences between the fundamental wave output voltages. The first single-phase full bridge circuit 10 and the second single-phase full bridge circuit 20 are configured to be controlled so as to be in a state corresponding to the phase difference. As a result, in the inverter unit 1, the first single-phase full bridge circuit 10 and the second single-phase full bridge circuit 20 are controlled so that the phase difference between the first voltage va1 and the second voltage va2 is approximately 90 degrees. can do. As a result, the pulsating component flowing through the common capacitor 30 can be further reduced. As a result, the power loss in the common capacitor 30 can be significantly reduced, and the efficiency of the inverter unit 1 can be improved. Further, since the pulsating component flowing through the common capacitor 30 can be further reduced, the temperature rise of the common capacitor 30 can be suppressed, and the life of the common capacitor 30 can be extended. Since the pulsating component flowing through the common capacitor 30 can be further reduced, the capacity of the common capacitor 30 can be further reduced, and the common capacitor 30 can be further miniaturized.

Further, in the first embodiment, as described above, at least one of the switching element 13 (23) and the diode 14 (24) contains silicon carbide. As a result, the power loss can be reduced as compared with the case where both the switching element 13 (23) and the diode 14 (24) are configured by the element made of silicon. As a result, the cooling mechanism portion of the first single-phase full bridge circuit 10 and the second single-phase full bridge circuit 20 can be miniaturized, so that the first single-phase full bridge circuit 10 and the second single-phase full bridge circuit 20 can be miniaturized. Can be easily arranged in the same inverter unit 1 (easily configured as a single unit).

[Second Embodiment]
Next, the configuration of the motor drive device 200 of the second embodiment will be described with reference to FIGS. 6 to 10. In the motor drive device 200 according to the second embodiment, unlike the motor drive device 100 according to the first embodiment in which m is configured as an even number, m is configured as an odd number, and an alternating current power of an odd number of m phases is transmitted to the motor 302. It is configured to be supplied. The same configuration as that of the first embodiment is shown with the same reference numerals in the drawings, and the description thereof will be omitted.

As shown in FIG. 6, in the second embodiment, the motor drive device 200 includes an odd number of m inverter units 201 and a control unit 250 that controls the drive of each inverter unit 201. Each of the m inverter units 201 is connected to a first single-phase full bridge circuit 210 and a second single-phase full bridge circuit 220, and a first single-phase full bridge circuit 210 and a second single-phase full bridge circuit 220. A common capacitor 30 is provided. Further, the electric motor 302 is provided with n windings 320 (twice m). The first single-phase full bridge circuit 210 is connected to the first winding 321 of the windings 320. The second single-phase full bridge circuit 220 is connected to the second winding 322 of the winding 320.

In the second embodiment, the control unit 250 has m-phase voltages va11-1 to va11-m (hereinafter, when not particularly distinguished) output to the first winding 321 shown in FIG. 7 in the m inverter units 201. , "Voltage va11") and the m-phase voltages va12-1 to va12-m (hereinafter, "voltage va12" unless otherwise specified) output to the second winding 322 shown in FIG. Control the first single-phase full bridge circuit 210 and the second single-phase full bridge circuit 220 so that they are synchronized with each other.

Specifically, the control unit 250 controls the voltage vectors vb11-1 to vb11-m of the first single-phase full bridge circuit 210 of each inverter unit 201 so as to have a phase difference obtained by dividing 360 degrees by m. It is configured as follows. Further, the control unit 250 is configured to control the voltage vectors vb12-1 to vb12-m of the second single-phase full bridge circuit 220 of each inverter unit 201 so as to have a phase difference obtained by dividing 360 degrees by m. Has been done. The phase difference obtained by dividing 360 degrees by m is an example of the "predetermined angle" in the claims. Further, the voltage vectors vb11-1 to vb11-m are examples of the "first fundamental wave output voltage vector group" in the claims, and the voltage vectors vb12-1 to vb12-m are in the claims. This is an example of the “second fundamental wave output voltage vector group”.

Then, the control unit 250 sets the voltage va11-2 and the voltage va12-2 so that the voltage va11-1 (voltage vector vb11-1) and the voltage va12-1 (voltage vector vb12-1) have the same phase. ..., The drive of each inverter unit 201 is controlled so that the voltage va11-m and the voltage vah12-m have the same phase. That is, the first winding 321 to which the voltages va11-1 to va11-m are applied constitutes the winding of the first group of m-phase. Further, the second winding 322 to which the voltages va12-1 to va12-m are applied constitutes the winding of the second group of m-phase.

Here, in the second embodiment, in the same inverter unit 201, the phase difference between the phase of the voltage va11 and the phase of the voltage va12 is the m-phase voltage output to the first winding 321. Of the phase differences between va11-1 to va11-m and the m-phase voltages va12-1 to va12-m output to the second winding 322, the phase difference closest to 90 degrees (combination of voltage vectors). ), The first single-phase full bridge circuit 210 and the second single-phase full bridge circuit 220 are controlled.

For example, when m = 11, the 11 inverter units 201 have 11-phase voltages va11-1 to va11-11 output to the first winding 321 shown in FIG. 7 and the second winding shown in FIG. The AC power is configured to be synchronized with the 11-phase voltages va12-1 to va12-11 output to 322. Specifically, the control unit 250 sets the voltage va11-2 and the voltage va12- so that the voltage va11-1 (voltage vector vb11-1) and the voltage va12-1 (voltage vector vb12-1) have the same phase. It is configured to control the drive of each inverter unit 201 so that the voltage v11-11 and the voltage v a12-11 have the same phase so that the voltage 2 and the voltage va11-11 have the same phase.

In this case, it is the voltage vector vb11-4 (vb12-4) and the voltage vector vb11-9 (vb12-9) that have the phase difference closest to 90 degrees with the voltage vector vb11-1 and 98.2. Degree (6π / 11). In this case, in the second embodiment, in the first (U1) inverter unit 201, the voltage va11-1 corresponding to the voltage vector vb11-1 is applied to the first single-phase full bridge circuit 210, and the first one is The two-single-phase full bridge circuit 220 is controlled by the control unit so that the voltage va12-4 corresponding to the voltage vector vb12-4 is applied. As shown in FIG. 9, in each inverter unit 201 other than the first inverter unit 201, the voltage applied to the first single-phase full bridge circuit 210 and the voltage applied to the second single-phase full bridge circuit 220. The phase difference with and from is controlled by the control unit 250 so as to be 98.2 degrees (6π / 11).

Then, in FIG. 10, the power factor cos θ is the power output from the first single-phase full bridge circuit 210 corresponding to the voltage v11-1 when 0.8 is taken as an example, as in the first embodiment. A certain first power p11-1, a second power p12-4 which is a power output from a second single-phase full bridge circuit 220 corresponding to a voltage v12-4, a first power p11-1 and a second power p12. The waveform (power (p11-1 + p12-4)) in which -4 is combined is shown. This synthesized waveform corresponds to the waveform in which α = 6π / 11 (98.2 degrees) in the above equation (17). In this case, the amplitude of the combined waveform is about 0.07 × VI, which is smaller than the amplitude of either the first power p11-1 or the second power p12-4, 0.5 × VI. Further, the other configurations of the second embodiment are the same as the configurations of the first embodiment.

[Effect of the second embodiment]
In the second embodiment, the following effects can be obtained.

In the second embodiment, as described above, m is a half of n and an odd number, and the control unit 250 is output from the m inverter units 201, and the phase difference is obtained by dividing 360 degrees by m. A group of m voltage vectors vb11-1 to 11-m is formed, and a group of m voltage vectors vb12-1 to 12-m having a phase difference obtained by dividing 360 degrees by m is formed. It is configured to control the first single-phase full bridge circuit 210 and the second single-phase full bridge circuit 220. As a result, even when driving the electric motor 302 to which the odd-numbered m-phase electric power is supplied, the first single-phase full bridge circuit 210 of one of the odd-numbered m and one of the odd-numbered m are driven. The second single-phase full bridge circuit 220 can be provided in the same inverter unit 201 and driven. As a result, even when the electric motor 302 to which the odd-numbered m-phase electric power is supplied is driven, the amplitude of the pulsating component of the electric power output from all the inverter units 201 can be reduced because the electric motor 302 is driven. Therefore, in all the common capacitors 30 arranged in the motor drive device 200, it is possible to reduce the power loss, suppress the temperature rise, and extend the life. The other effects of the second embodiment are the same as the effects of the first embodiment.

[Modification example]
It should be noted that the embodiments disclosed this time are exemplary in all respects and are not considered to be restrictive. The scope of the present invention is shown by the scope of claims rather than the description of the above-described embodiment, and further includes all modifications (modifications) within the meaning and scope equivalent to the scope of claims.

For example, in the first and second embodiments, two single-phase full-bridge circuits (first single-phase full-bridge circuit and second single-phase full-bridge circuit) are provided in the same inverter unit. The present invention is not limited to this. That is, three or more single-phase full bridge circuits may be provided in the same inverter unit.

For example, in the inverter unit 401 according to the modification shown in FIG. 11, a third single-phase full bridge circuit 404 is provided in addition to the first single-phase full bridge circuit 402 and the second single-phase full bridge circuit 403. The common capacitor 430 provided in the inverter unit 401 functions as a smoothing capacitor for the first single-phase full bridge circuit 402, the second single-phase full bridge circuit 403, and the third single-phase full bridge circuit 404. Then, in the same inverter unit 401, the phase difference between the phase of the voltage va21 of the first single-phase full bridge circuit 402 and the phase of the voltage va22 of the second single-phase full bridge circuit 403 is a value close to 60 degrees (for example). , 60 degrees), and the phase difference between the phase of the voltage va22 and the phase of the voltage va23 of the third single-phase full bridge circuit 404 becomes a value close to 60 degrees (for example, 60 degrees), and the voltage va23 The first single-phase full bridge circuit 402, the second single-phase full bridge circuit 403, and the third single phase so that the phase difference between the phase and the phase of the voltage va21 is close to 60 degrees (for example, 60 degrees). The full bridge circuit 404 is configured to be controlled by the control unit 450.

Further, in the first and second embodiments, the phase difference between the phase of the voltage va1 (voltage va11) and the phase of the voltage va2 (voltage va12) is 90 degrees (98.2 degrees) in the same inverter unit. Although an example is shown, the present invention is not limited to this. That is, when two single-phase full bridge circuits are provided in the same inverter unit, the motor is driven so that the phase difference is in the range of 60 degrees or more and 120 degrees or less and has a size other than 90 degrees and 98.2 degrees. The device may be configured.

Further, in the first embodiment, an example in which m is 6 and n is 12, and in the second embodiment, m is 11 and n is 22. The invention is not limited to this. That is, the motor drive device may be configured with m as an integer of 3 or more other than 6 and 11 and n as an integer of 3 or more other than 12 and 22.

Further, in the first and second embodiments, an example in which at least one of the switching element and the diode is configured to contain silicon carbide has been shown, but the present invention is not limited to this. If there is no problem in increasing the loss and the size of the switching element and the diode, both the switching element and the diode may be composed of an element made of silicon.

Further, in the first and second embodiments, the example in which the common capacitor is composed of a single capacitor is shown, but the present invention is not limited to this. That is, the common capacitor may be composed of a plurality of capacitors.

1,201,401 Inverter unit 10,210,402 1st single-phase full bridge circuit 11,21 Power supply side positive electrode terminal (DC power supply side terminal, single-phase full bridge circuit terminal)
12, 22 Power supply side negative electrode terminal (direct picture power supply side terminal, single-phase full bridge circuit terminal)
13, 23 Switching elements 14, 24 Diodes 20, 220, 403 Second single-phase full bridge circuit 30, 430 Common capacitors 50, 250, 450 Control unit 100, 200 Motor drive device 101 DC power supply 102, 302 Motor 120, 320 volumes Wires 121, 321 1st winding (1st winding)
122, 322 Second winding (second winding)

Claims (8)

The DC power input from the DC power supply is converted into AC power, and the AC power of multiple phases is output to an electric motor that is isolated from each other and has n windings (n is an integer of 6 or more). It is equipped with m inverter units (m is an integer of 3 or more) and a control unit.
The m inverter units each have a first single-phase full bridge circuit connected to the first winding of the n windings and a second connected to the second winding. A two-single-phase full-bridge circuit and a common capacitor connected to the terminal on the DC power supply side of the first single-phase full-bridge circuit and the second single-phase full-bridge circuit are provided.
The control unit has a first power output from the first single-phase full bridge circuit to the first winding and a second power output from the second single-phase full bridge circuit to the second winding. The first single-phase full bridge circuit and the said so that the amplitude of the pulsating component of the combined waveform in the common capacitor with the electric power is equal to or less than the amplitude of the pulsating component of either the first electric power or the second electric power. An electric power drive that controls the second single-phase full bridge circuit. In the same inverter unit, the control unit has the phase of the first fundamental wave output voltage output from the first single-phase full bridge circuit to the first winding, and the second single-phase full bridge circuit. The first single-phase full bridge circuit and the second single-phase so that the phase difference from the phase of the second fundamental wave output voltage output from the second winding to the second winding is 60 degrees or more and 120 degrees or less. The motor drive device according to claim 1, which controls a full bridge circuit. In the control unit, the phase difference between the phase of the first fundamental wave output voltage and the phase of the second fundamental wave output voltage is the phase difference between the fundamental wave output voltages output to the n windings. The motor drive device according to claim 2, wherein the first single-phase full bridge circuit and the second single-phase full bridge circuit are controlled so as to be in a state corresponding to the phase difference closest to 90 degrees. The m is half of the n and is
The control unit has a first voltage vector that is output from the m inverter units and is a voltage vector of the first fundamental wave output voltage, and m outputs from the m inverter units. The first single-phase full bridge circuit and the so as to form the n fundamental wave output voltage vectors having different phases by predetermined angles, including the second voltage vector which is the voltage vector of the second fundamental wave output voltage. The motor drive device according to claim 3, which controls the second single-phase full bridge circuit. The m is half of the n and is an odd number.
The control unit is a first fundamental wave output voltage that is output from the m inverter units and is composed of a first voltage vector that is a voltage vector of m first fundamental wave output voltages whose phases are different from each other by predetermined angles. A second basic consisting of a second voltage vector which is a voltage vector of m second fundamental wave output voltages which are output from the m inverter units and whose phases are different from each other by predetermined angles while forming a vector group. The electric motor drive device according to claim 3, which controls the first single-phase full bridge circuit and the second single-phase full bridge circuit so as to form a wave output voltage vector group. The motor drive device according to any one of claims 1 to 5, wherein each of the m inverter units is provided with a single common capacitor. The first single-phase full-bridge circuit and the second single-phase full-bridge circuit each have a switching element and a diode connected to the switching element in antiparallel.
The one according to any one of claims 1 to 6, wherein the common capacitor is connected to both positive and negative terminals of the first single-phase full bridge circuit and both positive and negative terminals of the second single-phase full bridge circuit. Electric drive device. The motor drive device according to claim 7, wherein at least one of the switching element and the diode contains silicon carbide.

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