JP6299915B1 - Surge voltage suppression device, power conversion device using the same, and multiphase motor drive device - Google Patents

Abstract

A surge voltage suppressor capable of suppressing a surge voltage without providing detailed savings in application conditions or selecting a resistor that allows excessive current, and a power converter and motor using the same A drive device is provided. A surge suppressor includes multiphase reactors 31u to 31w inserted in multiphase cables Lu to Lw that connect a multiphase motor 14 and a multiphase inverter 23 that drives the multiphase motor, And a diode bridge circuit 32 in which diode legs 33u to 33w each having an intermediate point connected to a multiphase cable between the phase reactor and the multiphase motor are connected in parallel. The potential side is individually connected to the DC high potential side and the DC low potential side of the multiphase inverter. [Selection] Figure 1

Description

  The present invention relates to a surge voltage suppressing device that suppresses a surge voltage applied to a multiphase motor, a power converter using the same, and a multiphase motor driving device.

  When a multi-phase motor is driven by a multi-phase inverter having three or more phases having a switching element, an excessive surge voltage is applied to the multi-phase motor according to the switching timing of the switching element, and the line-to-line or ground-to-ground of the multi-phase motor This may cause a dielectric breakdown of the motor winding or reduce the life of the insulating portion of the motor winding due to partial discharge.

  In order to suppress the surge voltage applied to the multiphase motor, a surge voltage suppression circuit described in Patent Document 1 has been proposed.

  In the surge voltage suppression circuit described in Patent Document 1, one end of a series circuit of a resistor and a capacitor is connected to each of a three-phase cable connected between a motor and an inverter that drives the motor. The other ends of the circuit are connected to each other and connected to the neutral point of the inverter DC voltage.

JP 2008-283755 A

  By the way, in the prior art described in the said patent document 1, the series circuit of resistance and a capacitor | condenser is connected to each of the three-phase cable between a motor and an inverter. For this reason, an excessive current flows in the surge suppression circuit under a specific condition, an abnormal heating of the resistance occurs, and in the worst case, there is a concern of burning. It is also known that the surge voltage applied to the motor increases due to the reflection phenomenon when the length of the cable connecting the inverter and the motor becomes longer than a certain length. Furthermore, when the resonance frequency due to the inductance of the cable and the capacitor of the surge suppression circuit matches or approaches the switching frequency of the inverter, an excessive current is generated due to series resonance.

  And the length of the cable connecting the inverter and the motor is various in accordance with the factory or plant to which the motor drive device is applied, and the switching frequency (carrier frequency) of the inverter is less than a dozen kHz. Therefore, it is very difficult to completely avoid the above-described conditions that cause an excessive current.

  As a result, it is necessary to place detailed restrictions (switching frequency and cable length) on the application conditions of the surge suppression circuit, and resistance that has a large allowable power that does not cause usability or burn out even if excessive current occurs The surge suppression circuit will become larger.

  Therefore, the present invention has been made paying attention to the above-mentioned problems of the prior art, and it is possible to reduce the surge voltage without providing detailed savings in application conditions or selecting a resistor that allows excessive current. An object of the present invention is to provide a surge voltage suppressing device that can be suppressed, a power conversion device using the same, and a motor driving device.

In order to achieve the above object, one aspect of the surge voltage suppression device according to the present invention is a multiphase interpolated in a multiphase cable that connects a multiphase motor and a multiphase inverter that drives the multiphase motor. comprising a reactor, a diode bridge circuit connected in parallel to the diode leg midpoint is individually connected to a multi-phase cable between the multiphase reactor and polyphase motor, the diode bridge circuit, a multi-phase diode leg A ground diode leg is connected in parallel, the midpoint of this ground diode leg is connected to ground, and the DC high potential side and low potential side of the diode bridge circuit are connected to the DC high potential side and DC low potential side of the multiphase inverter. Connected individually.

  Moreover, the one aspect | mode of the power converter device which concerns on this invention is equipped with the multiphase inverter which drives a multiphase motor, and the surge voltage suppression apparatus mentioned above.

  Furthermore, the motor drive device according to the present invention includes a multiphase motor, an inverter that drives the multiphase motor, and the surge voltage suppression device described above.

  According to one aspect of the present invention, since the surge voltage suppression device is configured by the multiphase reactor and the multiphase diode bridge circuit, the resonance problem and the limitation due to the excessive current are caused when the capacitor is used without using the capacitor. It is possible to provide a surge voltage suppressing device that is not received, a power conversion device using the same, and a motor driving device.

1 is a circuit diagram showing a first embodiment of the present invention. It is a figure explaining the generation | occurrence | production principle of a surge voltage, (a) is a circuit diagram, (b) is a wave form diagram. It is a figure explaining the suppression principle of a surge voltage, (a) is a circuit diagram, (b) is a waveform diagram. It is a wave form diagram which shows the surge voltage by the presence or absence of a voltage clamp type dV / dt filter. It is a circuit diagram which shows the 2nd Embodiment of this invention. It is a circuit diagram which shows the modification of 2nd Embodiment. It is a circuit diagram which shows the other modification of 2nd Embodiment.

  Next, an embodiment of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  Further, the embodiment described below exemplifies an apparatus and a method for embodying the technical idea of the present invention, and the technical idea of the present invention is the material, shape, structure, The layout is not specified as follows. The technical idea of the present invention can be variously modified within the technical scope defined by the claims described in the claims.

  First, a first embodiment of a motor drive device including a surge voltage suppression device representing one aspect of the present invention will be described.

  As shown in FIG. 1, the motor drive device 10 includes a three-phase AC power supply 11, a power conversion device 13 to which three-phase AC power output from the three-phase AC power supply 11 is input via a transformer 12, And a three-phase motor 14 driven by three-phase power output from the power converter 13.

  The power conversion device 13 includes a pulse width modulation (PWM) converter (hereinafter referred to as a PWM converter) 21 that converts three-phase AC power input from the transformer 12 via the three-phase reactor 20 into DC power, and the converter 21 And a three-phase inverter 23 that converts the DC power smoothed by the smoothing capacitor 22 into three-phase AC power and supplies it to the three-phase motor 14. Yes.

  Here, in the PWM converter 21, as shown in FIG. 1, a U-phase switching leg CSLu, a V-phase switching leg CSLv, and a W-phase switching leg CSLw are connected in parallel between the high-potential side wiring Lp and the low-potential side wiring Ln. Equipped with a full bridge circuit.

  In the U-phase switching leg CSLu, two switching elements Q11 and Q12 configured by, for example, insulated gate bipolar transistors (IGBT) are connected in series. Similarly to the U-phase switching leg CSLu, the V-phase switching leg CSLv and the W-phase switching leg CSLw are connected in series with the switching elements Q13, Q14 and Q15, Q16. Note that free-wheeling diodes D11 to D16 are connected to the switching elements Q11 to Q16 in antiparallel.

  Further, an intermediate point that is a connection point between the switching elements Q11, Q13, and Q15 of each switching leg CSLu, CSLv, and CSLw and the switching elements Q12, Q14, and Q16 is connected to the output side of the transformer 12.

  Furthermore, a gate signal composed of a pulse width modulation (PWM) signal is input to the gate of each switching element Q11 to Q16 from a gate drive circuit (not shown), thereby converting AC power from the transformer 12 into DC power. Output to the high potential side wiring Lp and the low potential side wiring Ln.

  The converter is not limited to the PWM converter 21, and a diode bridge rectifier circuit in which the switching elements Q11 to Q16 of the PWM converter 21 are replaced with diodes can be applied.

  As shown in FIG. 1, the three-phase inverter 23 includes a U-phase switching leg ISLu, a V-phase switching leg ISLv, and a W-phase between the high-potential side wiring Lp and the low-potential side wiring Ln to which the smoothing capacitor 22 is connected. A switching bridge ISLw is provided with a full bridge circuit connected in parallel.

  In the U-phase switching leg ISLu, for example, two switching elements Q21 and Q22 configured by insulated gate bipolar transistors (IGBT) are connected in series. Similarly to the U-phase switching leg ISLu, the V-phase switching leg ISLv and the W-phase switching leg ISLw are connected in series with the switching elements Q23, Q24 and Q25, Q26. Note that free-wheeling diodes D21 to D26 are connected to the switching elements Q21 to Q26 in antiparallel.

  In addition, the intermediate point that is the connection point between the switching elements Q21, Q23, and Q25 of each switching leg ISLu, ISLv, and ISLw and the switching elements Q22, Q24, and Q26 is a three-phase motor 14 via three-phase cables Lu, Lv, and Lw It is connected to the.

  Further, a gate signal composed of a pulse width modulation (PWM) signal is input to the gates of the switching elements Q21 to Q26 of the three-phase inverter 23 from a gate drive circuit (not shown). In this three-phase inverter 23, the DC power supplied from the high-potential side wiring Lp and the low-potential side wiring Ln to which the smoothing capacitor 22 is connected is converted into AC power, and the three-phase inverters are connected via the three-phase cables Lu, Lb and Lw. The phase motor 14 is supplied.

A voltage clamp type dV / dt filter 30 is provided on the three-phase cables Lu, Lv, and Lw between the three-phase inverter 23 and the three-phase motor 14. The voltage clamp type dV / dt filter 30 includes a three-phase reactor 31 inserted in the three-phase cables Lu, Lv, and Lw individually, and power receiving terminals tu, tv, and tw of the three-phase reactor 31 and the three-phase motor 14. And a diode bridge circuit 32 connected to a connection point between the two.
The three-phase reactor 31 includes a U-phase reactor 31u inserted in the three-phase cable Lu, a V-phase reactor 31v inserted in the three-phase cable Lv, and a W-phase reactor 31w inserted in the three-phase cable Lw. Have

  The diode bridge circuit 32 includes three sets of diode legs 33u, 33v and 33w connected in parallel between the high potential side wiring Lp1 and the low potential side wiring Ln1, and a ground diode leg 34.

  In the diode leg 33u, two diodes D31 and D32 are connected in series between the high potential side wiring Lp1 and the low potential side wiring Ln1, the cathode of the diode D31 is connected to the high potential side wiring Lp1, and the cathode is the cathode of the diode D32. The anode of the diode D32 is connected to the low potential side wiring Ln1. Further, an intermediate point between the diodes D31 and D32 is connected between the U-phase reactor 31u of the three-phase reactor 31 and the power receiving terminal tu of the three-phase motor 14.

  In the diode legs 33v and 33w, two diodes D33, D34, D35, and D36 are connected in series in the forward direction between the high-potential side wiring Lp1 and the low-potential side wiring Ln1 as in the diode leg 33u. An intermediate point between the diodes D33 and D34 is connected between the V-phase reactor 31v of the three-phase reactor 31 and the power receiving terminal tv of the three-phase motor 14, and an intermediate point between the diodes D35 and D36 is a W-phase reactor 31w of the three-phase reactor 31. The power receiving terminal tw of the three-phase motor 14 is connected.

  Similarly to the diode legs 33u to 33w, the ground diode leg 34 includes two diodes D41 and D42 connected in series in the forward direction between the high potential side wiring Lp1 and the low potential side wiring Ln1. The intermediate point between the diodes D41 and D42 is connected to the ground.

  The high potential side wiring Lp1 is connected to the high potential side wiring Lp of the power conversion device 13, and the low potential side wiring Ln1 is connected to the low potential side wiring Ln of the power conversion device 13.

  Here, the surge suppression principle of the voltage clamp type dV / dt filter 30 will be described.

  First, the principle of inverter surge generation will be described with reference to FIG. 2 showing one phase of the three-phase inverter 23 and the three-phase motor 14.

  In FIG. 2A, En is a DC intermediate voltage of the inverter, Zm is an input impedance of the motor, Ca is a cable between the inverter and the motor, and SW is a switching element on the high side of the inverter.

  In the principle circuit of FIG. 2A, a simple reactor L is connected between the switching element SW and the cable Ca as a surge suppression countermeasure component. The reactor L corresponds to the phase reactors 31u to 31w of the three-phase reactor 31 of the present embodiment, but it is known that a sufficient surge suppression effect cannot be obtained with this simple reactor L alone.

  That is, as shown in FIG. 2B, when the switching element SW is turned on at a certain time t0, the input voltage Vin output from the switching element SW immediately rises to the DC intermediate voltage En. On the other hand, the output voltage Vout of the reactor L gradually increases in a parabolic manner and reaches the DC intermediate voltage En. Then, due to the reflection phenomenon according to the cable Ca and the impedance Zm of the motor, the output voltage Vout rapidly increases from the DC intermediate voltage En at a time point t1, as shown in FIG. 2B, and then toward the DC intermediate voltage En. Gradually decreases. It should be noted here that the output voltage Vout of the reactor L becomes a surge voltage that is greater than the DC intermediate voltage En of the inverter, and this excessive surge voltage propagates to the three-phase motor 14 side to cause a motor malfunction. Give rise to

  Note that the output current Is of the reactor L gradually increases in the positive direction as the output voltage Vout increases as shown by the dotted line in FIG. 2B, but the output voltage Vout is sharper than the DC intermediate voltage En. It decreases from the increasing time t1, and then increases in the negative direction after becoming “0” at the time t2.

  In order to suppress this surge voltage, in this embodiment, as shown in the principle diagram shown in FIG. 3A, a diode D is connected in parallel with the reactor L, and the output voltage Vout of the reactor L is the DC intermediate voltage of the inverter. Clamp not to exceed En. A simulation result based on the principle diagram of FIG. 3A is shown in FIG.

  As shown in FIG. 3B, the switching element SW is turned on at time t0, and the input voltage Vin of the reactor L reaches the DC intermediate voltage En of the inverter. At this time, the output voltage Vout output from the reactor L is suppressed to the voltage change rate dV / dt and clamped to the DC intermediate voltage En, so that satisfactory dV / dt filter characteristics can be obtained. Moreover, since the energy of the reflected wave from the power receiving terminal of the motor is regenerated to the inverter through the diode D, there is also an advantage of high efficiency.

  FIG. 4 shows a comparison of the receiving terminal voltage of the motor with and without the dV / dt filter. In FIG. 4, the dotted line shows the motor voltage without the dV / dt filter, and the solid line shows the motor voltage with the dV / dt filter.

  As can be seen from FIG. 4, in the absence of the dV / dt filter, the motor voltage has a square-wave decay waveform, and the maximum peak value rises to 1080 V, which is nearly twice the DC intermediate voltage En = 600 V. On the other hand, when the dV / dt filter is provided, the attenuation waveform has a triangular waveform, and the maximum peak value is suppressed to 850 V, which is less than 1.5 times the DC intermediate voltage En. For this reason, a big effect is especially acquired in reduction of the wire insulation protection of a motor.

  The voltage clamp type dV / dt filter 30 in the first embodiment is obtained by converting the surge suppression circuit having the voltage clamp function shown in FIG. 3A into a three-phase circuit. Therefore, the voltage change rate dV / dt of the three-phase voltage output from the three-phase inverter 23 to the three-phase motor 14 can be suppressed, and each phase voltage of the three-phase voltage is clamped to the DC intermediate voltage En. Satisfactory dV / dt filter characteristics can be obtained. Moreover, since the energy of the reflected wave from the power receiving terminals tu to tw of the three-phase motor 14 is regenerated to the three-phase inverter 23 through the diode legs 33u to 33w of the diode bridge circuit 32, high efficiency can be achieved. Furthermore, the voltage clamp type dV / dt filter 30 can obtain a surge voltage suppression effect equivalent to the surge voltage suppression effect shown in FIG.

  Therefore, it is possible to provide a surge voltage suppression device that can effectively suppress the surge voltage, and to provide a power conversion device and a motor drive device that suppress the surge voltage using the surge voltage suppression device. it can.

  Further, according to the first embodiment, since no capacitor is required to suppress the surge voltage, series resonance due to the use of the capacitor does not occur. Therefore, application restrictions such as the cable length and the switching frequency of the three-phase inverter 23 can be greatly relaxed, and an easy-to-use surge voltage suppression device, power conversion device, and motor drive device can be provided.

  Further, in the voltage clamp type dV / dt filter 30, a ground diode leg 34 is connected in parallel to a three-phase diode bridge circuit 32 for voltage clamp, and an intermediate point of the ground diode leg 34 is connected to the ground. ing.

  Therefore, by clamping the output voltage of each phase reactor 31u to 31w of the three-phase reactor 31 by the voltage clamp type dV / dt filter 30 having the ground diode leg 34, the ground voltage is also clamped to the DC intermediate voltage En. Can do. Thereby, the ground voltage of the three-phase motor 14, that is, the surge voltage of the zero-phase component can also be reduced.

  Here, the surge voltage of the zero-phase component is a surge voltage generated between the frame potential of the three-phase motor 14 and the motor winding, and causes damage to the motor between the ground. In general, the surge voltage of the zero-phase component varies greatly depending on the grounding method and the number of parallel operations of the inverter and motor, in addition to the switching operation of the three-phase inverter and PWM inverter. But measures are difficult.

  However, in the first embodiment, the ground diode leg 34 is included in the diode bridge circuit 32, and the midpoint between the diodes D41 and D42 of the ground diode leg 34 is connected to the ground, so that the surge of the zero phase component is achieved. The voltage can also be clamped to the DC intermediate voltage En, and a great suppression effect can be obtained for the surge voltage of the zero-phase component.

  In addition, the effect of suppressing the surge voltage of the zero-phase component can be easily achieved by simply connecting the ground diode leg 34 whose ground is grounded in parallel to the diode bridge circuit 32 and the three-phase diode legs 33u to 33w constituting the rectifier bridge circuit. Can get to. In addition, the surge voltage suppression effect of the zero-phase component is not affected by the switching operation of the three-phase inverter or the PWM inverter, the grounding method, or the number of parallel operations of the inverter or motor.

  In the first embodiment, the case where the ground diode leg 34 is connected to the diode bridge circuit 32 constituting the voltage clamp type dV / dt filter 30 has been described. However, the ground diode leg 34 is omitted and rectification is performed. The diode bridge circuit 32 can also be configured with only the diode legs 33u to 33w for use.

  Next, a second embodiment of the surge voltage suppressor according to the present invention will be described with reference to FIG. In FIG. 5, the three-phase AC power source 11, the transformer 12, and the PWM converter 21 of the power conversion device 13 that constitute the motor driving device 10 are not shown.

  In the second embodiment, the return current that may occur in the first embodiment described above is attenuated.

  That is, in the second embodiment, as shown in FIG. 5, the intermediate points of the rectifying diode legs 33u, 33v and 33w constituting the diode bridge circuit 32 and the phase reactors 31u, 31v of the three-phase reactor 31 and Current limiting resistors Ru, Rv, and Rw are respectively connected between 31w and connection points of the three-phase motor 14 with the power receiving terminals tu, tv, and tw. Further, a leakage current suppression impedance Ze for suppressing leakage current is connected between the intermediate point of the ground diode leg 34 and the ground. Specifically, the leakage current suppression impedance Ze is a leakage current suppression resistor Re or a grounding capacitor Ce for suppressing a low frequency current component. The leakage current suppression impedance Ze may be a series circuit of a leakage current suppression resistor Re and a ground capacitor Ce for suppressing a low frequency current component.

  Other configurations have the same configurations as those of the first embodiment described above, and corresponding parts to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  A diode bridge circuit 32 is connected between the three-phase motor 14 side of each phase reactor 31 u to 31 w of the three-phase reactor 31 and the high-potential side wiring Lp and the low-potential side wiring Ln of the three-phase inverter 23 of the power converter 13. By doing so, a reflux current path is formed. This return current path is, for example, passed from the output side of each phase reactor 31u, 31v and 31w of the three-phase reactor 31 through the diodes D31, D33 and D35 on the high side of the diode legs 33u, 33v and 33w of the diode bridge circuit 32. This path returns to the input side of the phase reactors 31u, 31v, and 31w through the switching elements Q11, Q13, and Q15 on the high side of the phase inverter 23. The return current flowing through the return current path is equal to the peak value of the surge current.

  Although there is an inductance in the return current path, since there is no element that actively attenuates the current, the return current decay becomes very slow. This reflux current increases the current passing between the collectors and emitters of the switching elements Q21, Q23, and Q25, thereby increasing the switching loss, and increases the restrictions added to the existing product as a countermeasure device.

  The return current path includes the input side of each phase reactor 31u, 31v and 31w of the three-phase reactor 31, the switching elements Q22, Q24 and Q26 on the low side of the three-phase inverter 23, and the diode D32 on the low side of the diode bridge circuit 32. Also formed by D34 and D36.

  In the second embodiment, current-limiting resistors Ru, Rv, and Rw as the reflux current suppression resistors are connected between the three-phase reactor 31 and the diode bridge circuit 32 that are common paths of the two reflux current paths. For this reason, both the high-side return current and the low-side return current can be attenuated by the current limiting resistors Ru, Rv, and Rw, and the return current can be reduced. Therefore, an increase in switching loss due to the switching elements Q21 to Q26 of the three-phase inverter 23 can be suppressed. In this case, the resistance values of the individual current limiting resistors Ru, Rv, and Rw only need to be able to suppress the reflux current of each phase individually, so that a resistance with a relatively small resistance value can be applied, and heat generation is small. can do.

  Furthermore, since the leakage current suppression impedance Ze is connected between the intermediate point of the ground diode leg 34 and the ground, the leakage current flowing to the ground through the ground diode leg 34 can be suppressed by the leakage current suppression impedance Ze.

  In the second embodiment, the case where the current limiting resistors Ru to Rw are connected between the three-phase reactor 31 and the diode bridge circuit 32 has been described. However, the present invention is not limited to this. That is, as shown in FIG. 6, the current limiting resistors Ru to Rw in FIG. 5 are omitted, and instead of these, the high potential side wiring Lp1 and low potential side wiring Ln1 of the diode bridge circuit 32 and the high potential of the three-phase inverter 23 are used. Current limiting resistors Rp and Rn may be connected between the side wiring Lp and the low potential side wiring Ln. In this case, since the return current flowing through the current limiting resistors Rp and Rn increases as compared with the configuration of FIG. 5, a resistor having a large resistance value is required to suppress this, but the number of resistors is reduced. be able to.

Further, FIG. 7 omits the leakage current suppression impedance Ze in the configuration of FIG. 6 and between the high potential side wiring Lp1 and the low potential side wiring Ln1 between the current limiting resistors Rp and Rn and the diode bridge circuit 32. And a snubber capacitor Cs. By disposing the snubber capacitor Cs in the immediate vicinity of the diode bridge circuit 32, the overvoltage breakdown of the diode can be prevented. Further, the snubber capacitor Cs is set to 0. The capacitor is configured with a small capacitance of several μF or less, and has a smaller capacitance than the capacitor used in the surge voltage suppression circuit described in Patent Document 1. For this reason, since the unnecessary resonance frequency of the present invention is much higher than the switching frequency, an excessive current due to series resonance does not occur.
The snubber capacitor Cs can also be added in the circuits of FIGS.

  Moreover, although the said 1st and 2nd embodiment demonstrated the case where the three-phase motor 14 was driven by the three-phase inverter 23 which comprises the power converter device 13, a multi-phase motor more than four phases was a multi-phase inverter. The present invention can also be applied to driving. In this case, the diode bridge circuit 32 may be connected in parallel with a number of diode legs corresponding to the number of phases of the multiphase motor.

  In the first and second embodiments, the case where one power converter 13 drives one three-phase motor 14 has been described. However, one power converter 13 drives a plurality of three-phase motors 14. In this case, the present invention can be applied. Furthermore, the present invention can be applied to a case where a plurality of sets of three-phase inverters and three-phase motors are connected to one converter constituting the power conversion device 13.

  DESCRIPTION OF SYMBOLS 10 ... Motor drive device, 11 ... Three-phase alternating current power supply, 12 ... Transformer, 13 ... Power converter, 14 ... Three-phase motor, 20 ... Three-phase reactor, 21 ... Pulse width modulation (PWM) converter, 22 ... Smoothing capacitor, 23 ... Three-phase inverter, Lu-Lw ... Three-phase cable, tu-tw ... Power receiving terminal, 31 ... Three-phase reactor, 31u ... U-phase reactor, 31v ... V-phase reactor, 31w ... W-phase reactor, 32 ... Diode bridge circuit 33u: U phase diode leg, 33v: V phase diode leg, 33w: W phase diode leg, 34 ... Ground diode leg, Ru to Rw, Rp, Rn ... Current limiting resistance, Ze ... Leakage current suppression impedance, Cs ... Snubber capacitor

Claims (9)

A multi-phase reactor inserted in a multi-phase cable connecting between the multi-phase motor and the multi-phase inverter that drives the multi-phase motor;
A diode bridge circuit connected in parallel with a diode leg individually connected at a midpoint to a multiphase cable between the multiphase reactor and the multiphase motor;
In the diode bridge circuit, a ground diode leg is connected in parallel with the multiphase diode leg, and an intermediate point of the ground diode leg is connected to the ground,
The surge voltage suppressor in which the DC high potential side and the low potential side of the diode bridge circuit are individually connected to the DC high potential side and the DC low potential side of the multiphase inverter. Surge voltage suppressor of claim 1, the return current suppressing resistor in the current path through the diode bridge circuit is interposed. The surge voltage according to claim 2 , wherein the return current suppression resistor is connected between an intermediate point of each multiphase diode leg of the diode bridge circuit and a multiphase cable between the multiphase reactor and the multiphase motor. Suppression device. The return current suppression resistor is connected between the high potential side of the diode bridge circuit and the high potential side of the multiphase inverter, and the low potential side of the diode bridge circuit and the low potential side of the multiphase inverter. The surge voltage suppressor according to claim 2. The surge voltage suppression device according to any one of claims 1 to 4 , wherein a leakage current suppression impedance is connected between an intermediate point of the ground diode leg and ground . The surge voltage suppressing device according to any one of claims 1 to 5 , wherein a snubber capacitor is connected between a DC high potential side and a low potential side of the diode bridge circuit . A multi-phase reactor inserted in a multi-phase cable connecting between the multi-phase motor and the multi-phase inverter that drives the multi-phase motor;
A diode bridge circuit connected in parallel with a diode leg individually connected at a midpoint to a multiphase cable between the multiphase reactor and the multiphase motor;
The DC high potential side and the low potential side of the diode bridge circuit are individually connected to the DC high potential side and the DC low potential side of the multi-phase inverter,
It said diode bridge circuit for a DC high potential side and the snubber capacitor between the low potential side is connected Rusa over di voltage suppressor. A multi-phase inverter for driving a multi-phase motor;
The surge voltage suppression device according to any one of claims 1 to 7,
The power converter provided with. A multiphase motor,
A multiphase inverter for driving the multiphase motor;
The surge voltage suppression device according to any one of claims 1 to 7,
A multi-phase motor driving device.

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