JP5043915B2 - Motor drive power supply - Google Patents

Description

  The present invention relates to a motor drive power supply device having a regeneration function for returning regenerative power generated by a motor to a power source.

  FIG. 5 shows an example of the configuration of a conventional motor drive power supply device having a regeneration function, and FIG. 6 shows a time chart of operation waveforms of respective parts in the conventional motor drive power supply device shown in FIG. ing. In the conventional power supply device, the regenerative power of the motor is returned to the power supply by switching the bridge-connected transistors constituting the converter every 120 ° section of the voltage phase of the three-phase AC power supply. A motor drive power supply device is disposed between the three-phase AC power supply and the motor control device, and includes an AC reactor ACL, six transistors, six diodes, and a phase detection circuit for detecting the phase of the three-phase AC power supply, and 6 The power supply device is composed of a gate signal generation circuit that drives one transistor. When the motor performs the power running operation, the gates of the six transistors are in the off state. At this time, the three-phase alternating current input from the three-phase alternating current power supply is subjected to three-phase full-wave rectification through six diodes connected in parallel to six transistors, and a direct current is supplied to the motor control device. . The motor control device includes an inverter circuit that converts a direct current into an alternating current during power running and reversely converts the alternating current generated by the motor M into a direct current during regeneration. When power is returned from the motor M at the time of regeneration and the voltage of the DC part of the motor control device increases, six transistors as shown in FIG. 6 based on the phase of the three-phase AC power source detected by the phase detection circuit. Are sequentially turned on, and a current is supplied to each phase of the three-phase AC power source to return the DC power to the three-phase AC power source. The section in which each of the six transistors is turned on is a section of 120 ° in which the power supply voltage of each phase is higher than the power supply voltage of the other phase with respect to the upper phase (the phase in which the regenerative voltage is positive). The phase (the phase in which the regenerative voltage is negative) is a 120 ° interval in which the power supply voltage of each phase is lower than the power supply voltages of the other phases. In this conventional power supply device, when the instantaneous regenerative power from the motor M is large and the capacity of the drive power supply device is small, it cannot be sufficiently regenerated. In view of this, Japanese Patent Application Laid-Open No. 62-26192 (Patent Document 1) proposes a regenerative power control device 20 using resistance regeneration together as shown in FIG. In the apparatus 20 shown in FIG. 7, resistance regeneration circuits (13, 14) are provided in parallel to the power regeneration circuit (9). When the motor is decelerated, when the DC voltage of the inverter 4 is less than or equal to a predetermined value, the power regeneration circuit is operated to perform power regeneration to the AC power source. When the DC voltage of the inverter 4 is equal to or higher than a predetermined value, both the power regeneration circuit and the resistance regeneration circuit are operated, and the regenerative power is absorbed by both the power regeneration and the resistance regeneration.

  Japanese Patent Application Laid-Open No. 6-62584 (Patent Document 2) discloses a power supply device provided with timing adjusting means for the purpose of suppressing distortion of current regenerated in the power supply. The time chart of the operation | movement waveform of this well-known power supply device shown in FIG. 8 is shown. In this known power supply device, the period during which the transistor is turned on (see gate signal) is changed. As shown in FIG. 8, in this known power supply device, the timing adjustment means causes the regenerative current to flow in the phase having the maximum potential and the minimum potential compared to the other phases of the three-phase power supply voltages. As for the drive signal for, the output of the drive signal to the transistor for supplying a regenerative current to the phase is started from the time before the potential of the phase reaches the maximum potential. Then, the timing adjustment means outputs the drive signal until a time when the potential of the phase becomes the same potential as the potential of the other one phase through a period in which the potential of the phase is the maximum with respect to the other two phases, and thereafter does not show the maximum . In addition, the timing adjustment unit starts outputting the regenerative signal to the phase from the time before the potential of the phase becomes the minimum potential, so that the potential of the phase becomes the minimum potential with respect to the other two phases. The drive signal is output until a time when the potential becomes the same as the potential of the other one phase through the period shown and does not show the minimum.

Japanese Patent Laid-Open No. 62-26192 JP-A-6-62584

  In a motor drive power supply device using both conventional power regeneration and resistance regeneration, resistance regeneration is also used when the allowable power for power regeneration is not exceeded. Therefore, the power regeneration provided for energy saving cannot be used effectively. This is because the current flowing through the power supply during power regeneration is affected by the power supply impedance, and therefore the allowable power for power regeneration is not always reached when the DC voltage of the inverter reaches a predetermined value. In addition, when the motor is decelerated rapidly, steep regenerative power returns. In such a case, it is desirable to operate the resistance regeneration early to absorb the regenerative power. In such a case, if the absorption of regenerative power is delayed, the inverter DC voltage increases, the current regenerated in the power supply increases more than necessary, and an overcurrent alarm may be assumed depending on the situation. However, as shown in FIG. 8, in the current distortion suppression control in the conventional power regeneration, the two current-crested waveforms in the 120 ° energization section have almost the same maximum value. For this reason, when the resistance regeneration is performed when the two mountain-shaped waveforms of the current in the 120 ° energization section exceed the threshold value, the power supply device cannot perform a high-speed resistance regeneration operation.

  The object of the present invention has been made in view of the above points, and while using the maximum allowable power for power regeneration, suppressing the distortion of the current regenerated to the power source to some extent, and the resistance regeneration operates faster. Another object of the present invention is to provide a motor drive power supply device that is less likely to overcurrent.

The motor drive power supply device of the present invention includes a power regeneration circuit, a regeneration resistor circuit, a conduction signal generation circuit, a phase detector for detecting the phase of a multiphase AC voltage input to the power regeneration circuit, and a polyphase AC A current detector for detecting current. Power regeneration circuit includes a converter function for converting a polyphase alternating current from the polyphase AC power source into a direct current, a rectifying function of supplying DC power to the motor controller, the regenerative electric power regenerated from the motor control apparatus, And a regenerative function for operating a converter circuit including a plurality of bridge-connected switching elements to regenerate a polyphase AC power source. The regenerative resistor circuit is composed of a series circuit of a regenerative resistor and a switching circuit. The regenerative resistor circuit is provided between the DC output terminals of the power supply regenerative circuit, and is configured to consume regenerative power with the regenerative resistor by bringing the switching circuit into a conductive state. ing. Conduction signal generation circuit, at the time of regeneration, to generate a second conduction signal to a first conduction signal to turn on the switching elements, the switching circuit in a conductive state.

In the present invention, during regeneration, based on the output of the phase detector, a period during which the voltage of one phase of the multiphase AC voltage of the multiphase AC power supply is larger than the voltage of the other phase and the voltage of the one phase There decrease composed than the voltage of the other phases, is defined as a basic period of the switching element becomes conductive when regenerating the regenerative power to the one phase. And in particular, conductive signal generating circuit, so as to be higher than the peak of the current waveform generated after the peak of the first current waveform of one phase of the current generated in response to the basic period, the semiconductor switching element A first conduction signal is generated that sets the conduction period from before the basic period starts to before the basic period ends. The conduction signal generation circuit conducts the switching circuit of the regenerative resistor circuit during the period when the maximum phase AC current among the multiphase AC currents is greater than or equal to a predetermined reference current greater than the allowable current value of the switching element. A second continuity signal is generated to enter a state.

According to the present invention, when generating the first conduction signal to until the conduction signal generation circuit basic period ends before the base time period the conduction period of the semiconductor switching element is started for power regeneration, the base time period The peak of the first current waveform of the current of one phase generated correspondingly becomes higher than the peak of the current waveform generated later. If this is done, the distortion of the current regenerated in the power supply slightly increases, but the distortion of the current regenerated in the power supply is suppressed as compared with the normal 120 ° energization control. In addition, a second conduction signal is generated to turn on the switching circuit of the regenerative resistor circuit during a period in which the maximum phase AC current is equal to or greater than a predetermined reference current greater than the allowable current value of the switching element. Then, resistance regeneration can be operated at an early stage, and regenerative power exceeding the power regeneration can be absorbed by resistance regeneration. As a result, the allowable power for power regeneration can be utilized to the maximum extent. As a result, according to the present invention, the DC voltage of the main circuit becomes high and the power supply current does not increase.

The multi-phase AC power supply is generally a three-phase AC power supply. In this case, the power regeneration circuit includes a converter circuit composed of six semiconductor switching elements connected in a bridge and a semiconductor rectifying element connected in a bridge. In addition, the conduction signal generating circuit is configured so that, during regeneration, the voltage of one phase of the three-phase AC voltage of the three-phase AC power supply is larger than the voltages of the other two phases, based on the output of the phase detector. the period in which the voltage of one phase is smaller than the voltage of the other two phases, when defining the basic period of two of the switching element becomes conductive when regenerating the regenerative power to the one phase , to be higher than the peak of the current waveform generated after the peak of the first current waveform of one phase of the current generated in response to the basic period, the conduction period of the two semiconductor switching elements is fundamental period The first conduction signal is generated from the start to the end of the basic period.

  The basic period is preferably greater than 120 ° in electrical angle. If it does in this way, distortion of the current regenerated to a power supply will be controlled compared with usual 120 ° energization control.

The reference current is preferably determined to a value that prevents the semiconductor switching element is destroyed by the regenerative current. Thus it is possible to reliably protect the semiconductor switching element.

It is a figure which shows schematic structure of an example of embodiment of the motor drive power supply device of this invention. It is a figure which shows the structure which generate | occur | produces a 2nd conduction signal. (A) thru | or (D) is a figure which shows the operation | movement waveform of each part of embodiment of FIG. (A) thru | or (D) is a figure which shows the operation | movement waveform in the case of decelerating a motor rapidly. It is a figure which shows the structure of the conventional motor drive power supply device. FIG. 7 is an operation waveform diagram of each unit in FIG. 6. It is a figure which shows the structure of the other conventional motor drive power supply device. FIG. 8 is an operation waveform diagram of each unit in FIG. 7.

  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of an example of an embodiment of a motor driving power supply device of the present invention. An AC reactor ACL is connected to the three-phase AC power supply AC, and transistors Tr1 to Tr6 as six semiconductor switching elements are bridge-connected to the output to constitute a converter circuit CV. Six diodes D1 to D6 are connected in parallel to the six transistors Tr1 to Tr6, respectively. The six diodes D1 to D6 form a bridge-connected three-phase rectifier circuit. A power regeneration circuit PR is configured by the bridged transistors Tr1 to Tr6 and the diodes D1 to D6.

  Between the DC output terminals of the converter circuit CV, a series circuit of a parallel circuit of a regenerative resistor R and a transistor Tr7 constituting a switching circuit and a diode D7 is connected in parallel. This series circuit constitutes a resistance regeneration circuit RR. The resistance regenerative circuit RR is configured to consume regenerative power by the regenerative resistor R by turning on the transistor Tr7 (switching circuit).

  A smoothing capacitor C is connected in parallel between the DC output terminals of the converter circuit CV. A motor controller MC including an inverter circuit is connected to both ends of the smoothing capacitor C. This inverter circuit converts direct current into alternating current and provides a three-phase alternating current motor M with a three-phase alternating current having a predetermined frequency as a motor current. The inverter circuit operates as a converter that converts an alternating current generated by the motor M into a direct current when the motor M decelerates to a regenerative state.

  A phase detector PD is connected to the output side of the AC reactor ACL connected to the R phase, the S phase, and the T phase. A current detector CD is connected to the output side of the AC reactor ACL connected to the R phase and the S phase. The current detector CD detects the R-phase and S-phase AC currents, calculates the T-phase AC current from these AC currents, and outputs it.

Outputs of the current detector CD and the phase detector PD are input to the conduction signal generation circuit SG. The conduction signal generation circuit SG includes a plurality of first conduction signals S for conducting the six transistors Tr1 to Tr6 constituting the converter in the power regeneration circuit PR during the power running and regeneration of the motor M [FIG. ) S1 to S6] and a second conduction signal S ′ for making the transistor Tr7 in the resistance regeneration circuit RR conductive when regenerating. In the present embodiment, during regeneration, based on the output of the phase detector PD, a period in which the voltage of one phase of the three-phase AC voltage output from the three-phase AC power supply AC is larger than the voltage of the other phase. and the voltage of said one phase a becomes smaller than the voltage of the other phases, is defined as a basic period T of the switching element becomes conductive when regenerating the regenerative power to the one phase. In particular, the conduction signal generation circuit SG sets the conduction period CT (signal width of the conduction signals S1 to S6) of the transistors Tr1 to Tr6 at the time of regeneration from before the basic period T to before the basic period T ends. 1 conduction signals S1 to S6 are generated. FIG. 3 clearly shows the basic period T and the conduction period CT for the R phase. The period in which the R-phase voltage is larger than the S-phase and T-phase voltages and the period in which the R-phase voltage is smaller than the S-phase and T-phase voltages are set to the conductive state when regenerating regenerative power in the R-phase. Is defined as a basic period T of the two transistors Tr1 and Tr4. The rise rp of the conduction signals S1 and S2 defining the conduction period CT of these two transistors Tr1 and Tr4 is set before the basic period T starts, and the fall fp of the conduction signals S1 and S2 is set before the basic period T ends. Yes. The conduction periods of the transistors corresponding to other phases are similarly determined. In FIG. 3B, the conduction signals S3 and S4 are the gate signals of the two transistors Tr2 and Tr5 for the S phase. The conduction signals S5 and S6 are gate signals for the two transistors Tr3 and Tr6 for the T phase. The conduction period CT is a current waveform in which a peak P1 of the first current waveform [for example, W1 in FIG. 3C] of one phase (for example, R phase) generated corresponding to the basic period T is generated later. [For example, W2 in FIG. 3C] is determined to be higher than the peak P2.

  When the conduction signal generation circuit SG generates the first conduction signals S1 to S6 for power supply regeneration, the peak P1 of the first current waveform W1 of the current of one phase generated corresponding to the basic period T is Becomes higher than the peak P2 of the current waveform W2 generated from. In this way, the distortion of the current regenerated in the power supply AC slightly increases, but the distortion of the current regenerated in the power supply AC is suppressed as compared with the normal 120 ° energization control.

  In addition, as shown in FIG. 3C, the conduction signal generation circuit SG has a predetermined phase AC current that is the maximum among the three-phase AC currents that is greater than or equal to the allowable current value of the transistors Tr1 to Tr6 (switching elements). During the period when the reference current (ri, -ri) is exceeded, the second conduction signal S ′ [see FIG. 3D] for generating the transistor Tr7 of the regenerative resistance circuit RR is generated. In order to generate the second conduction signal S ′, as shown in FIG. 2, the conduction signal generating circuit SG includes a maximum value detector MD that detects the AC current of the maximum phase among the three-phase AC currents, The comparator CP is provided for determining a period during which the alternating current of the phase to be equal to or greater than a predetermined reference current (ri, -ri). The transistor Tr7 of the regenerative resistor circuit RR is in a conductive state during the period in which the AC current of the maximum phase is equal to or greater than a predetermined reference current (ri, -ri) that is greater than or equal to the allowable current value of the transistors Tr1 to Tr6. When the second conduction signal S ′ is generated, the resistance regeneration can be operated earlier than in the prior art, and the regenerative power exceeding the power regeneration can be absorbed by the resistance regeneration. As a result, the allowable power for power regeneration can be utilized to the maximum extent.

The operation of the embodiment shown in FIG. 1 will be briefly described below with reference to FIG. FIG. 4 is an operation waveform diagram when the motor is suddenly decelerated. When the motor M performs a power running operation, the gates of the transistors Tr1 to Tr6 are off. Then, three-phase full-wave rectification is performed from the three-phase AC power supply AC through the diodes D1 to D6 connected in parallel to the transistors Tr1 to Tr6, and power is supplied to the motor control device MC. When the motor M is in a decelerating state, the motor M is in a regenerative state, and regenerative power is returned from the motor M to the power supply side, and the voltage of the DC unit of the motor control device MC increases [see FIG. 4 (C)]. Based on the phase of the three-phase AC voltage detected by the phase detector PD, as shown in FIG. 3B, the transistors Tr1 to Tr6 are in a conduction state during the conduction period specified by the conduction signals S1 to S6. As a result, the regenerative current flows through each phase and returns the regenerative power that is increasing the voltage of the DC section to the power supply AC. As described above, when the conduction period CT in which the transistors Tr1 to Tr6 are turned on is determined, the section in which the one-phase transistor is conducting becomes longer than in the past, and there are two currents in the 120 ° conduction section of the power regeneration current. The peak P1 of the first waveform W1 is higher than the peak P2 of the later waveform W2. Further, as shown in FIGS. 3C and 4B, the maximum current among the three-phase power supply currents exceeds the threshold value, that is, the reference current (ri, -ri) (current allowed by the transistor). During this period, the second conduction signal S ′ is output. When the conduction signal S ′ makes the transistor Tr7 conductive, a regenerative current flows through the regenerative resistor R, and the regenerative power exceeding the power regeneration is absorbed by the regenerative resistor. As a result, the allowable power for power regeneration can be utilized to the maximum extent. As shown in FIG. 4 (D), a plurality of second conduction signal period S 'are generated, periodically resistance regeneration is performed, the resistance regenerative current Ru flows. When the maximum current among the three-phase power supply currents becomes smaller than the reference current (ri, -ri), the second conduction signal S 'is not generated. As a result, thereafter, only the first conduction signals S1 to S6 are generated, only the power regeneration is performed, and the motor speed is reduced.

The AC reactor ACL may be disposed behind the connection point of the current detection circuit. Further, the phase detection circuit PD may be arranged before the ACL.

As described above, according to the present embodiment, in the motor drive power supply device using both resistance regeneration and power regeneration, the timing at which each of the transistors Tr1 to Tr6 is turned on and off at the time of power regeneration is set to the normal 120 °. since early compared with energization control, when compared to the prior art described in Patent Document 2 strain of current regenerated in the power source is increased slightly. However, the distortion of the current regenerated in the power supply is suppressed as compared with the normal 120 ° energization control. Further, the peak of the first waveform of the power regeneration current waveform appearing in the 120 ° energization section can be increased, and the resistance regeneration can be operated more quickly. As a result, the DC voltage in the main circuit does not increase and the power regeneration current does not increase. In addition, because resistance regeneration is controlled by the magnitude of the power supply current during power regeneration, the resistor regeneration operates after using all the allowable power regeneration capability, and the regenerative resistance capacity can be reduced. The energy saving effect is increased.

  According to the present invention, the resistance regeneration is controlled according to the magnitude of the power supply current during the power regeneration, so that the resistance regeneration is performed after using all the allowable power regeneration capabilities. As a result, the capacity of the regenerative resistor can be reduced, and the energy saving effect is increased.

Tr1 to Tr7 Transistors D1 to D7 Diode CV Converter circuit MC Motor controller M Motor AC Three-phase AC power source CD Current detector PD Phase detector SG Conduction signal generator circuit PR Power source regeneration circuit RR Resistance regeneration circuit

Claims (4)

A converter function for converting a polyphase alternating current from the polyphase AC power source into a direct current, a rectifying function of supplying DC power to the motor controller, the regenerative electric power regenerated from the motor controller side, are bridge-connected A power regeneration circuit having a regeneration function of operating a converter circuit including a plurality of switching elements to regenerate the polyphase AC power;
A regenerative resistor circuit comprising a series circuit of a regenerative resistor and a switching circuit, provided between the DC output terminals of the power supply regenerative circuit, and consuming regenerative power by the regenerative resistor by making the switching circuit conductive.
During power running and during regeneration, a first conduction signal for conducting a plurality of switching elements, wherein during regeneration, and conductive signal generating circuit for generating a second conduction signal to said switching circuit in a conductive state ,
A phase detector for detecting the phase of the polyphase AC voltage input to the power regeneration circuit;
A current detector for detecting the polyphase alternating current;
The conduction signal generation circuit is configured so that, during the regeneration, based on the output of the phase detector, the voltage of one phase of the multiphase AC voltage of the multiphase AC power supply is larger than the voltage of the other phase and the period in which the voltage of said one phase is smaller than the voltage of the other phase, when defining the basic period of the switching element becomes conductive when regenerating the regenerative power to the one phase, the basic period so that the peak of the first current waveform of the current of the one phase that occurs in response is higher than the peak of the current waveform generated later, the conduction period of the semiconductor switching element is the basic period begins The first conduction signal is generated from before to before the end of the basic period, and the AC current of the maximum phase among the multiphase AC currents is determined in advance not less than an allowable current value of the switching element. Reference current Period which is above the regenerative resistor circuit of the switching circuit power supply for driving a motor apparatus characterized by a generating a second conduction signal to the conductive state. The multi-phase AC power source is a three-phase AC power source,
The power regeneration circuit includes the converter circuit including six semiconductor switching elements connected in a bridge and a semiconductor rectifying element connected in a bridge.
The conduction signal generation circuit is configured such that, during the regeneration, the voltage of one phase of the three-phase AC voltage of the three-phase AC power supply is larger than the voltages of the other two phases based on the output of the phase detector. definition voltage period and said one phase and becomes smaller than the voltage of the other two phases, the basic period of two of the switching element becomes conductive when regenerating the regenerative power to the one phase when the as the peak of the first current waveform of said one phase of the current generated in response to the basic period is higher than the peak of the current waveform generated later, of the two semiconductor switching elements The switching element generates the first conduction signal having a conduction period from before the basic period starts to before the basic period ends, and the one-phase alternating current that is the maximum among the three-phase alternating currents is the switching element. Allowable current Period is equal to or higher than above a predetermined reference current, the power source for driving a motor according to claim 1, characterized in that to generate the second conduction signal to the switching circuit in a conductive state of said regenerative resistor circuit apparatus.   The motor drive power supply device according to claim 2, wherein the basic period is greater than 120 ° in electrical angle. The reference current, the motor driving power supply device according to claim 2 which is determined to a value that prevents the said semiconductor switching element is destroyed by the regenerative current.

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