JP5631260B2 - AC motor drive device - Google Patents

Description

  The present invention suppresses the peak power of the AC motor drive device by using the energy stored in the power storage device during the power running operation of the AC motor, and charges the power storage device with the regenerative energy during the regenerative operation of the AC motor. The present invention relates to an AC motor driving device that suppresses a peak of electric power consumed by heat and heat regenerated from an AC motor to a system power supply.

  Conventionally, a converter that converts AC power of a system power source supplied from a power plant or a substation facility in a factory into DC power, an inverter that converts DC power into AC power different from the AC power of the system power source, and the converter A technology of an AC motor drive device that assists energy during a power running operation using a power storage circuit including a power storage device connected in parallel to a DC bus between the inverter and the inverter is disclosed (for example, Patent Document 1). reference).

Japanese Patent No. 4333916

  In the technology described in Patent Document 1 disclosed in the background art, it is possible to suppress the peak power of the AC motor drive device by using the energy stored in the power storage device during the power running operation of the AC motor. If the regenerative energy is charged to the power storage device from the start of the regenerative operation of the motor and the charge capacity of the power storage device is exceeded, the surplus regenerative energy is regenerated to the grid power source regardless of the amount of regenerative energy, or the converter It is converted to heat energy and is wasted.

  In general, since a large amount of electric power is sharply regenerated at the start of regenerative operation, it is necessary to increase the current standards of the reactor and other parts that constitute the power storage circuit for the power storage device. As a result, the device becomes larger and the resources used increase. There were problems such as. In addition, the prior art also has a problem that a technical disclosure regarding a processing method for a sharp regeneration of a large electric power at the start of the regeneration operation has been made.

  The present invention has been made to solve the above-described problems, and can suppress not only the peak power amount supplied from the system power supply but also the peak power amount during the regenerative operation of the AC motor. An object of the present invention is to provide an AC motor drive device that can effectively reduce the amount of peak power regenerated to a system power supply and the amount of power consumed by a converter without increasing the size of the device.

  In order to solve the above-described problems, the present invention provides a converter that converts AC system power into DC power when driving an AC motor, and the DC power obtained by this converter is an AC voltage or frequency suitable for the AC motor. An inverter that converts the electric power to supply to the AC motor, and is connected in parallel to the inverter, assists a part of the power running power by the discharging operation of the electric storage device provided inside the AC motor, and An AC motor driving apparatus that includes a power storage circuit that charges part of the regenerative power by a charging operation of the power storage device during the regenerative operation of the AC motor employs the following configuration.

In the case where powering power larger than a preset first threshold is used in the AC motor, the power storage circuit is configured to store the power storage device based on a voltage value and a current value of DC power on the output side of the converter. A power running power compensation unit for generating a current command value to be discharged;
When regenerative power having an absolute value larger than a preset second threshold value is regenerated from the AC motor, a current command for charging the power storage device based on the voltage value and current value of DC power on the output side of the converter A regenerative power compensator for generating a value;
The power storage device based on a voltage value and a current value of DC power on the output side of the converter, a voltage value between both ends of the power storage device, and an input / output current value within a preset third threshold value and a fourth threshold value. An auxiliary charge control unit that generates a current command value for charging and discharging the power storage device in order to set the voltage value at both ends of the first voltage value to a predetermined voltage value, and the absolute value of the third threshold is the first value The absolute value of the fourth threshold value is smaller than the absolute value of the threshold value, and is smaller than the absolute value of the second threshold value.

According to the present invention, not only the peak power amount supplied from the system power supply can be suppressed, but also the peak power amount during the regenerative operation of the AC motor can be suppressed, and the steep power at the start of the regenerative operation can be achieved. It is possible to suppress the occurrence of peak power even with respect to the occurrence of regeneration. In addition, a supplementary charge control unit is provided, and the third threshold value and the fourth threshold value are set in advance in the supplementary charge control unit, and the absolute value of the third threshold value is set by the power running time power compensation unit. The absolute value of the fourth threshold value is set to be smaller than the absolute value of the second threshold value set in the regeneration power compensation unit, and the third threshold value is set to be smaller than the absolute value of the threshold value. Since the current command value for charging / discharging the power storage device is generated within the range of the fourth threshold, the peak power can be suppressed more reliably during regeneration. Thereby, it becomes possible to effectively reduce the peak power amount regenerated to the system power supply and the power amount consumed by the converter without increasing the size of the apparatus.

It is a block diagram which shows the whole AC motor drive device which concerns on Embodiment 1 of this invention. It is a block diagram of the electrical storage circuit which comprises the same AC motor drive device. FIG. 3 is a circuit diagram illustrating an example of a chopper circuit constituting the power storage circuit of FIG. 2. It is a block diagram which shows the charging / discharging control circuit which comprises the electrical storage circuit of FIG. FIG. 5 is a block diagram of a power running time power compensation unit constituting the charge / discharge control circuit of FIG. 4. It is a block diagram of the electric power compensation part at the time of regeneration which constitutes the charging / discharging control circuit of FIG. It is a block diagram of the auxiliary charge control part which comprises the charge / discharge control circuit of FIG. It is a block diagram of the addition part which comprises the charging / discharging control circuit of FIG. It is a block diagram of the voltage command value production | generation part which comprises the charging / discharging control circuit of FIG. FIG. 5 is a block diagram of a control signal generation unit constituting the charge / discharge control circuit of FIG. 4. It is a block diagram explaining an example of the dead time production | generation part which comprises the control signal production | generation part of FIG. It is a wave form diagram with which it uses for operation | movement description of the alternating current motor drive device which concerns on Embodiment 1 of this invention. It is a block diagram which shows the charging / discharging control circuit which comprises the electrical storage circuit in the alternating current motor drive device which concerns on Embodiment 2 of this invention. It is a block diagram of the addition part which comprises the charging / discharging control circuit of FIG. It is a block diagram explaining an example of the small command value determination part which comprises the addition part of FIG. It is a block diagram of the voltage command value production | generation part which comprises the charging / discharging control circuit of FIG. It is a block diagram of the control signal generation part which comprises the charging / discharging control circuit of FIG. It is a block diagram which shows the charging / discharging control circuit which comprises the electrical storage circuit in the alternating current motor drive device which concerns on Embodiment 3 of this invention. It is a block diagram of the control signal generation part which comprises the charging / discharging control circuit of FIG. It is a block diagram explaining an example of the normalization part which comprises the control-signal production | generation part of FIG. It is a block diagram of the electrical storage circuit in the alternating current motor drive device which concerns on Embodiment 4 of this invention. It is a circuit diagram which shows an example of the chopper circuit which comprises the electrical storage circuit of FIG. It is a block diagram of the charging / discharging control circuit which comprises the electrical storage circuit of FIG. It is a block diagram of the voltage command value generation part which comprises the charging / discharging control circuit of FIG. It is a block diagram of the control signal generation part which comprises the charging / discharging control circuit of FIG. It is a block diagram of the charging / discharging control circuit which comprises the electrical storage circuit in the alternating current motor drive device which concerns on Embodiment 5 of this invention. It is a block diagram of the addition part which comprises the charging / discharging control circuit of FIG. It is a block diagram explaining an example of the gate signal generation part which comprises the addition part of FIG. FIG. 27 is a block diagram of a dead time generation unit that gives a dead time to a control signal generated by a control signal generation unit constituting the charge / discharge control circuit of FIG. 26. FIG. 7 is a block diagram of an Icap2 * generation unit that constitutes the regenerative power compensation unit of FIG. 6. It is a wave form diagram explaining the operation | movement at the time of regeneration operation | movement in the electric power compensation part at the time of regeneration provided with the structure of the Icap2 * production | generation part of FIG. It is a block diagram which shows the part of the electric power compensation part at the time of regeneration of the charging / discharging control circuit which comprises the electrical storage circuit in the alternating current motor drive device which concerns on Embodiment 6 of this invention. FIG. 33 is a block diagram of an Icap2 * generation unit that constitutes the regenerative power compensation unit of FIG. 32. It is a wave form diagram explaining the operation | movement at the time of regeneration operation | movement in the electric power compensation part at the time of regeneration provided with the structure of the Icap2 * production | generation part of FIG. It is a wave form diagram explaining operation | movement of the Icap3 * production | generation part provided in the electric power compensation part at the time of regeneration of the charging / discharging control circuit which comprises the electrical storage circuit in the alternating current motor drive device which concerns on Embodiment 6 of this invention. In FIG. 35, it is a wave form diagram which expands and shows a part in the time-axis direction at the time of a regeneration start. It is a block diagram which shows the whole AC motor drive device which concerns on Embodiment 9 of this invention. It is a block diagram of the electrical storage circuit which comprises the same AC motor drive device of FIG. It is a flowchart with which it uses for description of the charging / discharging control operation | movement of the charging / discharging control circuit which comprises the electrical storage circuit of FIG.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing the entire AC motor driving apparatus according to Embodiment 1 of the present invention.
The AC power of the AC system power supply 1 supplied from the power plant or substation equipment in the factory is converted into DC power by the converter 2 and output to the DC bus 3. The DC power supplied by the DC bus 3 is converted by the inverter 4 into AC power suitable for an AC motor 5 described later. The voltage and frequency of the AC power output from the inverter 4 do not necessarily match the voltage and frequency of the AC power of the system power supply 1. The AC motor 5 is driven by AC power supplied from the inverter 4, and performs operations according to purposes such as processing, transportation, movement, and exercise. On the other hand, a storage circuit 6 is connected to the DC bus 3 in parallel with the inverter 4, and a DC bus voltage value Vdc and a DC bus current value Idc that is an output current value of the converter 2 are input to the storage circuit 6.

  The power storage circuit 6 assists part of the power running power by the discharge operation of the power storage device 61 described later during the power running operation of the AC motor 5, and the regenerative power by the charging operation of the power storage device 61 during the regenerative operation of the AC motor 5. It is provided to suppress both peak power during powering operation and regenerative operation of the AC motor by accumulating a part. As shown in FIG. 2, the power storage circuit 6 mainly includes a power storage device 61, a chopper circuit 62, and a charge / discharge control circuit 63 for controlling the chopper circuit 62.

  The electricity storage device 61 is configured by, for example, an electrolytic capacitor, an electric double layer (EDLC), or a storage battery. And the high voltage | pressure side terminal of the electrical storage device 61 is connected to the below-mentioned reactor 623 which comprises the chopper circuit 62, and the low voltage | pressure side terminal is connected to the low voltage | pressure side DC bus 3b. Here, the chopper circuit 62 is a step-down bidirectional chopper circuit, one of which is connected to the DC bus 3 (3a, 3b) and the other is connected to the power storage device 61.

  The charge / discharge control circuit 63 detects and inputs all of the DC bus voltage value Vdc, the DC bus current value Idc, the voltage value Vcap across the storage device 61, and the charge / discharge current value Icap of the storage device 61. Based on this value, control signals SWP and SWN for controlling switching elements 621 and 622 (described later) in the chopper circuit 62 to a “ON” state or “OFF” state are generated and output to the chopper circuit 62. To do.

  An example of the chopper circuit 62 is shown in FIG. The chopper circuit 62 is connected to the high-voltage side DC bus 3a, the switching element 621 controlled by the control signal SWP output from the charge / discharge control circuit 63, and the low-voltage side DC. A switching element 622 that is connected to the bus 3 b and is controlled to be in a “ON” state or a “OFF” state by a control signal SWN output from the charge / discharge control circuit 63, and one terminal is a switching element 621 and a switching element 622. And the other terminal is connected to the high-voltage side terminal of the electricity storage device 61. Each of the switching elements 621 and 622 is formed of, for example, an IGBT or a transistor and a diode connected in antiparallel to the transistor.

  The control signals SWP and SWN have the “ON” state and the “OFF” state of the switching elements 621 and 622 controlled by the respective control signals SWD and 622 except for the dead time set to prevent a short circuit of the DC bus 3. In the dead time period, the control signals SWP and SWN both control the switching elements 621 and 622 to be turned off to prevent the DC bus 3 from being short-circuited. When one control signal SWP has a higher ratio of the “communication” state than the other control signal SWN, charging of the power storage device 61 is performed, and vice versa. . The details of the operation of the chopper circuit 62 are not the main part of the present invention, and the description thereof will be omitted.

  The charge / discharge control circuit 63 controls charge / discharge of the electricity storage device 61 by control signals SWP, SWN given to the switching elements 621, 622 in the chopper circuit 62. As shown in FIG. 4, the charge / discharge control circuit 63 includes two multipliers 631, 632, a power running power compensation unit 633, a regeneration power compensation unit 634, an auxiliary charge control unit 635, an adder 636, a voltage command value. A generation unit 637 and a control signal generation unit 638 are provided.

  One multiplier 631 calculates the product of the DC bus voltage value Vdc and the DC bus current value Idc, and generates the output power Pcnv of the converter 2. The power Pcnv is output to the power running power compensation unit 633, the regeneration power compensation unit 634, and the auxiliary charge control unit 635, respectively. The other multiplication unit 632 calculates the product of the both-end voltage value Vcap of the power storage device 61 and the charge / discharge current value Icap, and outputs the product as the input / output power Pcap of the power storage device 61 to the auxiliary charge control unit 635.

  Here, for convenience of explanation, the DC bus current value Idc is positive in the direction flowing out of the converter 2, and the charge / discharge current value Icap of the power storage device 61 is positive in the direction of charging the power storage device 61. By defining the direction of each current in this way, the power Pcnv on the output side of the converter 2 is positive when the inverter 4 consumes power and is negative when the power is regenerated from the inverter 4. In addition, the input / output power Pcap of the power storage device 61 is represented by positive power for charging the power storage device 61 and negative power for discharging from the power storage device 61.

  When the AC motor 5 is in power running, the power running power compensation unit 633 has a power running power compensation threshold LPU that is the first threshold value set in advance when the AC motor 5 is in power running. The current command value Icap1 * for discharging the electricity storage device 61 is generated.

  That is, as shown in FIG. 5, the power running power compensation unit 633 stores in advance a power running power compensation threshold LPU that limits the power Pcnv on the output side of the converter 2 during the power running operation of the AC motor driving device. Here, the power running power compensation threshold LPU is a positive value. The power running power compensation unit 633 compares the power Pcnv and the power running power compensation threshold LPU, and when the power Pcnv exceeds the power running power compensation threshold LPU, the power Pcnv is converted into the power running power compensation threshold. The command value Icap1 * of the current to be discharged from the power storage device 61 is generated by the Icap1 * generating unit 6331 according to the power difference E1 when exceeding the LPU, and is output to the adding unit 636. When the power difference E1 is calculated as expressed by the following (formula 1), the power difference E1 becomes a positive value when the power Pcnv exceeds the power-computing power compensation threshold LPU. On the other hand, when the power Pcnv does not exceed the power running power compensation threshold LPU, the power difference E1 is a negative value. In response to this E1, the Icap1 * generating unit 6331 generates a current command value Icap1 * that commands the amount of current that discharges the power storage device 61. When Icap1 * becomes a positive value, the current command value Icap1 * The output is controlled to be “0”. Therefore, the current command value Icap1 * output to the adder 636 is always a negative value or a value of “0”. The Icap1 * generation unit 6331 generally uses PI control, but there is no problem in realizing the present embodiment regardless of PID control, P control, or I control.

  E1 = Pcnv-LPU (Formula 1)

  As will be described later, regeneration power compensation unit 634 generates regeneration power compensation threshold value LPL, which is a second threshold value, in which output side power Pcnv of converter 2 that is the regeneration power during regeneration of AC motor 5 is preset. A current command value Icap2 * for charging the electricity storage device 61 when it exceeds is generated.

  That is, as shown in FIG. 6, the regeneration power compensation unit 634 stores a regeneration power compensation threshold LPL that limits the power Pcnv on the output side of the converter 2 during the regeneration operation of the AC motor drive device. Here, LPL is a negative value. Then, the regenerative power compensation unit 634 compares the power Pcnv and the regenerative power compensation threshold LPL, and according to the power difference E2 when the power Pcnv falls below the regenerative power compensation threshold LPL, the power storage device 61 Is generated by the Icap2 * generating unit 6341 and output to the adding unit 636.

  Here, since the power Pcnv and the regeneration power compensation threshold LPL are both negative values, when the power Pcnv falls below the regeneration power compensation threshold LPL, | Pcnv |, which is the absolute value of the power Pcnv, It means that it becomes larger than | LPL | which is the absolute value of the compensation threshold LPL. When the power difference E2 is calculated as expressed by the following (formula 2), when the power Pcnv is lower than the regeneration power compensation threshold LPL, the power difference E2 becomes a negative value. On the other hand, when the power Pcnv exceeds the regenerative power compensation threshold LPL, the power difference E2 is a positive value. In response to E2, the Icap2 * generation unit 6341 generates a current command value Icap2 * that commands the amount of current to charge the power storage device 61. If Icap2 * becomes a negative value, the current command value Icap2 * The output is controlled to be “0”. Therefore, the current command value Icap2 * output to the adding unit 636 is always a positive value or a value of “0”. The Icap2 * generation unit 6341 generally uses PI control, but there is no problem in realizing the present embodiment in PID control, P control, or I control.

  E2 = Pcnv-LPL (Formula 2)

  As shown in (Equation 4) described later, the auxiliary charging control unit 635 determines the difference between the output side power Pcnv of the converter 2 and the input / output power Pcap of the power storage device 61, that is, the load Pload of the inverter 4 and the AC motor 5. , A preset third threshold and a positive value during the power supplementary charging control unit operation threshold LSU, and a preset fourth threshold and a negative value during the regeneration auxiliary charge control unit operation threshold A current command value Icap3 * for charging / discharging the power storage device 61 so that the voltage value Vcap at both ends of the power storage device 61 is maintained at a preset desired voltage value VcapTH when within the range of LSL It is.

  That is, as shown in FIG. 7, the auxiliary charge control unit 635 stores in advance the desired voltage value VcapTH that the AC motor drive device user of the present invention desires to hold and store the voltage Vcap across the power storage device 61. Has been. The desired voltage value VcapTH is a voltage that controls a reference voltage for restoring the voltage Vcap across the storage device 61 at the start of use of the AC motor drive device or at the end of a series of operations, that is, a voltage value that controls the reference charge amount of the storage device 61. is there. Then, the auxiliary charge control unit 635 compares the voltage value Vcap at both ends of the power storage device 61 with the desired voltage value VcapTH, and instructs a current amount for charging / discharging the power storage device 61 according to the voltage difference E3. The command value Icap3 * is generated by the Icap3 * generating unit 6351 and output to the adding unit 636.

The relationship between the voltage difference E3 and the current command value Icap3 * will now be described by taking as an example the case where the voltage difference E3 is calculated by the following (Equation 3).
When the voltage difference E3 is positive, it means that the voltage value Vcap at both ends of the power storage device 61 is larger than the desired voltage value VcapTH, and therefore, a negative current command value Icap3 * for discharging the power storage device 61. And the voltage value Vcap across the power storage device 61 is reduced. Conversely, when the voltage difference E3 is negative, a positive current command value Icap3 * for charging the power storage device 61 is generated, and the both-ends voltage value Vcap of the power storage device 61 is increased. In general, PI control is used for the Icap3 * generation unit 6351. However, there is no problem in realizing the present embodiment in PID control, P control, or I control.

  E3 = Vcap−VcapTH (Formula 3)

    Pload = Pcnv−Pcap (Formula 4)

  As described above, Pload represents the load of the inverter 4 and the AC motor 5. When the load Pload is positive, the AC motor drive device is in a power running operation. Conversely, when the load Pload is negative, the AC motor drive device is in a regenerative operation.

  The auxiliary charging control unit 635 stores a power running auxiliary charging control unit operation threshold LSU that is a predetermined positive value and a regeneration auxiliary charging control unit operation threshold LSL that is a predetermined negative value. The Icap3 * generation unit 6351 restricts the current command value Icap3 * by the following (formula 5) when 0 <Pload <LSU, and when LSL <Pload <0: In other cases, that is, in the case of Pload> LSU or Pload <LSL, the limit shown in the following (Expression 7) is set.

0 <Icap3 * <(LSU-Pload) / Vcap (Formula 5)
(LSL-Pload) / Vcap <Icap3 * <0 (Formula 6)
Icap3 * = 0 (Formula 7)

  Here, when LPU> LSU and LPL <LSL are set, the auxiliary charging control unit 635 can be controlled to operate when the power running power compensation unit 633 and the regeneration power compensation unit 634 are not operating. Become. That is, the Icap3 * generation unit 6351 of the auxiliary charge control unit 635 is configured so that the load Pload obtained by the above (Equation 4) is within the range between the power running auxiliary charge control unit operation threshold LSU and the regeneration auxiliary charge control unit operation threshold LSL. (LSL <Pload <LSU), the current command value Icap3 * corresponding to the value of the voltage difference E3 given by the above (formula 3) is generated.

  When the load Pload is between the power running power compensation threshold LPU and the power running supplementary charge control unit operation threshold LSU (LSU <Pload <LPU), or the regeneration power compensation threshold LPL and the regenerative supplement charge control unit operation. When it is between the threshold value LSL (LPL <Pload <LSL), the charge / discharge control circuit 63 does not output any current command value Icap1 *, Icap2 *, Icap3 *, resulting in a dead zone. This is a measure for surely suppressing peak power during powering and regeneration of the AC motor 5.

  As shown in FIG. 8, the adding unit 636 includes a current command value Icap1 * output from the power running power compensation unit 633, a current command value Icap2 * output from the regenerative power compensation unit 634, and the auxiliary charging control unit 635. The integrated current command value Icap * is generated by adding the output current command value Icap3 *.

  As shown in FIG. 9, the voltage command value generation unit 637 compares the integrated current command value Icap * output from the addition unit 636 with the charge / discharge current value Icap of the power storage device 61 and calculates the current difference E4. To do. Then, according to the current difference E4, the Vcap * generation unit 6371 generates a voltage command value Vcap * that charges and discharges the power storage device 61 and commands the reached value of the both-end voltage value Vcap of the power storage device 61. The data is output to the control signal generation unit 638 in the next stage.

  When calculating the current difference E4 as expressed by the following (Equation 8), the Vcap * generator 6371 charges the power storage device 61 according to the value of the current difference E4 when the current difference E4 is positive. The voltage command value Vcap * is output so as to increase. Conversely, when the current difference E4 is negative, the voltage command value Vcap * is discharged so that the power storage device 61 is discharged according to the value of the current difference E4. Output to decrease Note that PI control is generally used for the Vcap * generation unit 6371, but there is no problem in realizing the present embodiment regardless of PID control, P control, or I control.

  E4 = Icap * −Icap (Formula 8)

  As shown in FIG. 10, the control signal generation unit 638 includes a normalization unit 6381, a triangular wave generation unit 6382, a comparator 6383, and a dead time generation unit 6384. The dead time generation unit 6384 includes a DC bus. In order to prevent the short circuit 3, a dead time Td that prescribes a time width during which the switching elements 621 and 622 in the chopper circuit 62 are simultaneously turned off is set in advance.

  The normalizing unit 6381 receives the voltage command value Vcap * that is the output of the voltage command value generating unit 637, and outputs a normalized signal Nol that is normalized. In this case, the normalization signal Nol is “0” when the AC motor driving device of the present invention is in a no-load state during neither the power running operation nor the regenerative operation. Note that the normalizing unit 6381 is expressed by the following (Equation 9) when, for example, the AC motor driving device is unloaded and the DC bus voltage value when the chopper circuit 62 does not perform charging / discharging operation is Vcap0. It can also be configured as follows.

  Nol = Vcap * −Vcap0 (Formula 9)

  The triangular wave generation unit 6382 outputs a triangular wave signal Tri having a direct current component “0”. The comparator 6383 outputs a signal PWM that is in the state “1” when Nol ≧ Tri and is in the state “0” when Nol <Tri.

  The dead time generation unit 6384 controls the control signal when the signal PWM shifts from the “1” state to the “0” state and when the signal PWM shifts from the “0” state to the “1” state. A dead time Td is added and output so that both SWP and SWN are in the “off” state.

An example of the dead time generation unit 6384 is shown in FIG.
In FIG. 11, 63841 and 63842 are one-shot multivibrator elements that output a pulse having a time width Td with respect to the rising edge of the input, 63843 and 63844 are 2-input AND elements, and 63845 to 63847 are NOT elements. is there. The signal PWM is input to the one-shot multivibrator element 63841, the 2-input AND element 63843, and the NOT element 63845, respectively. The one-shot multivibrator element 63841 outputs a pulse P1P having a time width Td from the rising edge of the signal PWM and inputs it to the NOT element 63638. The NOT element 63846 outputs a pulse P1C obtained by inverting the pulse P1P, and inputs the pulse P1C to the other input terminal of the 2-input AND element 63843. Therefore, the AND element 63384 outputs a control signal SWP that is short in the state of “1” by the time width Td from the rising edge of the signal PWM of “1”. On the other hand, the output of NOT element 63845, which is an inverted signal of signal PWM, is input to one-shot multivibrator element 63842 and two-input AND element 63844, respectively. The one-shot multivibrator element 63842 outputs a pulse P2P having a time width Td from the rising edge of the inverted signal of the signal PWM, that is, the falling edge of the signal PWM, and inputs the pulse P2P to the NOT element 63847. The NOT element 63847 outputs a pulse P2C obtained by inverting the pulse P2P, and inputs the pulse P2C to the other input terminal of the 2-input AND element 63844. Therefore, the AND element 63844 outputs the control signal SWN in which the period shorter by the time width Td from the falling edge is “1” than the “0” state of the signal PWM. In this way, the control signals SWP and SWN to which the dead time Td that always keeps “0” for the time width Td with respect to the change point of the signal PWM are generated.

  Next, the operation of the AC motor driving apparatus in the first embodiment will be described with reference to FIG.

  Here, the case where the drive control of AC motor 5 used for machine tools, such as press work and cutting, is performed as an example is assumed. In this case, since driving / stopping of the AC motor 5 is frequently repeated, the AC motor driving device repeatedly generates a power running operation state and a regenerative operation state. For this reason, the load Pload changes as shown by the solid line in FIG. Also, the power running power compensation threshold value LPU stored in the power running power compensation unit 633 and the regeneration power compensation threshold value LPL stored in the regenerative power compensation unit 634 are respectively indicated by a one-dot chain line in FIG. Furthermore, the power running auxiliary charge control unit operation threshold value LSU and the regeneration auxiliary charge control unit operation threshold value LSL stored in the auxiliary charge control unit 635 are indicated by a two-dot chain line in FIG.

In such a case, the power difference E1 between the power Pcnv on the output side of the converter 2 in the power running power compensation unit 633 and the power running power compensation threshold LPU is the case where the load Pload exceeds the power running power compensation threshold LPU (FIG. 12). During the period from time T3 to time T4 in (a), a positive value is obtained as shown in FIG. 12B, but the electric power Pcnv on the output side of the converter 2 is obtained by the discharging operation from the power storage device 61 according to the present invention. Since the power difference E1 is suppressed, the amplitude of the power difference E1 is small, while the power difference E1 in other cases (period T0 to time T3 and time T4 to time T9 in FIG. 12A) is a negative value.
With respect to the power difference E1, the Icap1 * generating unit 6331 in the power running time power compensating unit 633 is “0” during the period from time T0 to time T3 in FIG. Thus, the period from the time T3 to the time T4 becomes a negative value, and when it increases rapidly after the time T4 to “0”, the current command value Icap1 * that continues “0” is output thereafter.

  Similarly, the power difference E2 between the power Pcnv on the output side of the converter 2 in the regenerative power compensation unit 634 and the regenerative power compensation threshold LPL is obtained when the load Pload has a regenerative amount larger than the regenerative power compensation threshold LPL ( In the period from time T5 to time T6 in FIG. 12A, a negative value is obtained as shown in FIG. 12D. However, the power on the output side of the converter 2 is obtained by the charging operation of the power storage device 61 according to the present invention. Since Pcnv is suppressed, the amplitude of the power difference E2 is small. On the other hand, the power difference E2 in other cases (period T0 to time T5 and time T6 to time T9 in FIG. 12A) is a positive value. . For this power difference E2, the Icap2 * generation unit 6341 in the regenerative power compensation unit 634 is “0” during the period from time T0 to time T5 in FIG. 12A, as shown in FIG. Thus, although the period from time T5 to time T6 is a positive value, when it decreases gradually to “0” due to a decrease in the regenerative electric energy, a current command value Icap2 * that continues “0” is output thereafter.

When the load Pload is equal to or higher than the regeneration auxiliary charge control unit operation threshold LSL and equal to or less than the power running auxiliary charge control unit operation threshold LSU (time T0 to time T2 and time T4 to time T4 in FIG. 12A). The current command value Icap3 * is output based on the voltage difference E3 between the both-end voltage value Vcap and the desired voltage value VcapTH of the power storage device 61 during the time T5 and the period from the time T7 to the time T9. The Icap3 * generating unit 6351 outputs “0” to the current command value Icap3 * because the voltage difference E3 is “0” during the period from time T0 to time T2 in FIG. During the period from time T4 to time T5, since the power storage device 61 performs a discharging operation according to the current command value Icap1 *, the voltage value Vcap across the power storage device 61 decreases as shown in FIG. The voltage difference E3 becomes a positive value and outputs a positive value to the current command value Icap3 *. Since the power storage device 61 performs a charging operation by the current command value Icap2 * after time T7 in FIG. Since the both-end voltage value Vcap rises exceeding VcapTH as shown in FIG. 12 (h), the voltage difference E3 becomes a negative value, and a negative value is set to the current command value Icap3 *. Output until VcapTH is reached, then output “0”.
As can be seen from (c), (e), and (f) of FIG. 12, the integrated current command value Icap * that is the output of the adder 636 is as shown in FIG. Since the voltage command value generating unit 637 generates the voltage command value Vcap * based on the integrated current command value Icap *, the both-ends voltage value Vcap of the power storage device 61 is controlled as shown in FIG. . As shown in FIG. 12 (j), due to charging / discharging of the power storage device 61 in accordance with the fluctuation of the both-end voltage value Vcap, the upper limit of the power Pcnv on the output side of the converter 2 is the power running power compensation threshold LPU and the lower limit is It is suppressed so as not to exceed the power compensation threshold value LPL during regeneration.

  By configuring the AC motor drive device as in the first embodiment, it becomes possible not only to suppress the peak power amount supplied from the system power source 1 to the power running power compensation threshold LPU, but also during the regenerative operation. It is possible to suppress the peak power amount for regenerating the power to the system power supply 1 and the power amount consumed by the inverter 4 to the regeneration power compensation threshold LPL. In this way, since the peak power amount regenerated to the system power supply and the power amount consumed by the converter 2 can be suppressed, it is possible to use the converter 2 that is small and lightweight and has a small rating (specification). The whole can be made small.

Embodiment 2. FIG.
An embodiment that enables stable control in the AC motor driving device of the present invention will be described. In the second embodiment, the same numbers are assigned to blocks, circuits, or elements having the same or equivalent functions as those in the first embodiment.

  In the second embodiment, as shown in FIG. 13, there is an invalidation signal Disable output from the adder 636, and this invalidation signal Disable is output to the voltage command value generator 637 and the control signal generator 638. This is different from the first embodiment in that the voltage value Vcap at both ends of the power storage device 61 is also input to the voltage command value generation unit 637. The different parts will be described below with reference to the drawings.

  First, in addition to the function of generating integrated current command value Icap * described in the first embodiment, addition unit 636 determines whether the value of integrated current command value Icap * is small as shown in FIG. And a time width TΔ for ensuring stability are stored. The threshold IΔ is compared with the integrated current command value Icap *, so that the integrated current command value Icap * is within the range of the following (formula 10). A small command value determination unit 6361 that generates an invalidation signal Disable indicating a small value, and an integrated current command when the invalidation signal Disable determines that the integrated current command value Icap * is small. And a switch 6362 for forcibly setting the value Icap * to “0”. However, here, for convenience of explanation, the threshold value IΔ is a positive value. IΔ can be set to a value such as 1/50 or 1/100 of the saturation current value of reactor 623 in chopper circuit 62, for example.

  −IΔ <Icap * <IΔ (Equation 10)

  An example of the small command value determination unit 6361 is shown in FIG. In the small command value determination unit 6361, the integrated current command value Icap *, which is the sum of the three current command values Icap1 *, Icap2 *, and Icap3 *, is the “−” terminal of the comparator 63611 and the “+” of the comparator 63612. Input to the terminal. The threshold value IΔ is input to the “+” terminal of the comparator 63611 and the inverter 63613. The inverter 63613 receives the threshold value IΔ and outputs the value of −IΔ to the “−” terminal of the comparator 63612. The comparator 63611 outputs a signal D1 that becomes “1” when the integrated current command value Icap * is less than the threshold value IΔ to one input terminal of the two-input AND element 63614. The comparator 63612 outputs a signal D2 that is in a “1” state when the integrated current command value Icap1 * is greater than the threshold value −IΔ to the other input terminal of the 2-input AND element 63614. Therefore, the output signal D3 of the 2-input AND element 63614 becomes “1” when the above (Equation 10) is satisfied, and is output to the one-shot multivibrator element 63615 and the 2-input AND element 63617. The one-shot multivibrator element 63615 outputs to the NOT element 63616 a pulse that is in a “1” state only for a period of time width TΔ from the rising edge of the signal D3. The output of the NOT element 63616 is output to the other input terminal of the 2-input AND element 63617, and an invalidation signal for determining that the value of the integrated current command value Icap * is small over the period of the time width TΔ in order to prevent chattering Disable is generated.

  In voltage command value generation unit 637, both-end voltage value Vcap of power storage device 61 and invalidation signal Disable from addition unit 636 are input to Vcap * generation unit 6371 as shown in FIG. When determining that the integrated current command value Icap * is small based on the invalidation signal Disable, the Vcap * generation unit 6371 controls to replace the voltage command value Vcap * with the voltage Vcap across the power storage device 61. If it is determined by this control that the integrated current command value Icap * is not small, the voltage command value Vcap * resumes charge / discharge control of the power storage device 61 from the both-end voltage value Vcap regardless of the past circumstances. To do.

In the control signal generation unit 638, as shown in FIG. 17, when the invalidation signal Disable is input to the dead time generation unit 6384 and the invalidation signal Disable indicates that the integrated current command value Icap * is small, The control signals SWP and SWN to be output from the dead time generation unit 6384 are both forcibly masked so as to be in the “off” state. That is, when the integrated current command value Icap * is small and the invalidation signal Disable is output, the control signals SWP and SWN are in the “OFF” state over the period of the time width TΔ, and the operation of the chopper circuit 62 is stopped. The charge / discharge of the electricity storage device 61 is not performed.
Since other configurations are the same as those of the first embodiment, detailed description thereof is omitted here.

  By configuring as in the second embodiment, it becomes possible to suppress the peak power amount during power running and the peak power amount during regeneration, and the AC motor drive device is not in the power running operation state or the regenerative operation state. In spite of being in a steady state, it is possible to prevent the steady state from being lost due to disturbance or current ripple. Further, even when the steady state is deviated, the charge / discharge control of the power storage device 61 can be always restarted from the steady state without depending on the past control state.

Embodiment 3 FIG.
In the first embodiment, the control signal generator 638 of the charge / discharge control circuit 63 generates the control signals SWP and SWN from the voltage command value Vcap *. However, in the third embodiment, the DC bus voltage value is further increased. A case where Vdc is also used will be described. Note that the third embodiment can be applied to either the first embodiment or the second embodiment, but when applied to the first embodiment, focusing on the simplicity of explanation. I will explain it. In the third embodiment, the same numbers are assigned to blocks, circuits, or elements having the same or equivalent functions as those in the first embodiment.

FIG. 18 shows a block diagram of the charge / discharge control circuit 63 in the third embodiment.
As a feature of the third embodiment, the DC bus voltage value Vdc is also input to the control signal generator 638 in addition to the multiplier 631.
When the chopper circuit 62 of the AC motor driving apparatus of the present invention is a step-down bidirectional chopper circuit as shown in FIG. 3, the load Pload is unloaded, that is, “0”, and charging / discharging of the power storage device 61 is performed. In the absence, the following relationship (Equation 11) is established.

  2 · Vcap = Vdc (Formula 11)

  Therefore, in the third embodiment, as shown in FIG. 19, the voltage command value Vcap * and the DC bus voltage value Vdc are input to the normalization unit 6381 in the control signal generation unit 638. In the normalizing unit 6381, as shown in FIG. 20, the divider 636381 calculates Vcap * / Vdc, the multiplier 63812 doubles the result, and the subtractor 63813 calculates the output value of the multiplier 63812. In this method, the normalized signal Nol is obtained by subtracting the numerical value “1”.

By configuring the normalizing unit 6381 in this way, the voltage command value Vcap * becomes the both-ends voltage value Vcap when there is no load and the power storage device 61 is not charged / discharged. From this relationship, the normalization signal Nol is “0”, and a positive value is used when the voltage command value Vcap * is used to control the voltage value Vcap across the power storage device 61 to a value higher than ½ of the DC bus voltage value Vdc. On the contrary, when the normalization signal Nol is to be controlled to a value lower than ½ of the DC bus voltage value Vdc by the voltage command value Vcap *, the normalization signal of negative value is used. Nol is output respectively.
Since other configurations are the same as those in the first embodiment, detailed description thereof is omitted here.

  By configuring the AC motor drive device as in the third embodiment, it becomes possible to suppress the peak power amount during power running and the peak power amount during regeneration, and the voltage command value Vcap * at that time By instructing the increase / decrease with respect to the voltage value Vcap at both ends of the power storage device 61, charge / discharge control of the power storage device 61 with quick response can be performed.

Embodiment 4 FIG.
In the first to third embodiments, the case where the chopper circuit 62 has a single phase has been described. However, the chopper circuit 62 in the AC motor driving device according to the present invention is limited to such a single phase. Therefore, here, as an example, the case where the chopper circuit 62 has three phases will be described by focusing on the simplicity of the description and applied to the first embodiment. In the fourth embodiment, the same numbers are assigned to blocks, circuits, or elements having the same or equivalent functions as those in the first embodiment.

  The power storage circuit 6 of the fourth embodiment includes a three-phase step-down bidirectional chopper circuit 62 as shown in FIG. 21, and the currents at the output terminals a, b, and c of each chopper circuit 62. Each value is detected and output to the charge / discharge control circuit 63 as current values IcapA, IcapB, and IcapC. The three output terminals a, b, and c after detecting the current values IcapA, IcapB, and IcapC are connected to the high-voltage side terminal of the electricity storage device 61. The control signals SWPa, SWNa, SWPb, SWNb, SWPc, and SWNc output from the charge / discharge control circuit 63 are all supplied to the chopper circuit 62.

  As shown in FIG. 22, the chopper circuit 62 includes upper and lower switching elements 621a and 622a controlled by control signals SWPa and SWNa between a high-voltage side DC bus 3a and a low-voltage side DC bus 3b. Two upper and lower switching elements 621b and 622b controlled by SWPb and SWNb and two upper and lower switching elements 621c and 622c controlled by control signals SWPc and SWNc are connected in parallel, respectively. One terminal of the reactor 623a is connected to the connection point of the upper and lower switching elements 621a and 622a, one terminal of the reactor 623b is connected to the connection point of the upper and lower switching elements 621b and 622b, and the upper and lower switching elements 621c and 622c are connected to each other. One terminal of the reactor 623c is connected to the connection point. The other terminals of the reactors 623a, 623b, and 623c are drawn out of the chopper circuit 62 as an output terminal a, an output terminal b, and an output terminal c, respectively, and commonly connected to the high-voltage side terminal of the power storage device 61.

  In the charge / discharge control circuit 63, as shown in FIG. 23, the input current values IcapA, IcapB, and IcapC are input to the voltage command value generation unit 637, and the sum of the three current values is added by the addition unit 639. Calculated. Then, the output of the adding unit 639 is multiplied by the voltage value Vcap at both ends of the power storage device 61 by the multiplication unit 632 to calculate the input / output power Pcap of the power storage device 61 and is output to the auxiliary charge control unit 635. Note that the configuration and operation of the auxiliary charging control unit 635 are basically the same as those in the first embodiment, and thus detailed description thereof is omitted here.

  As shown in FIG. 24, the voltage command value generation unit 637 has one of the addition units 6372a, 6372b, and 6372c, which is a current command value IcapA * obtained by multiplying the integrated current command value Icap * obtained by the addition unit 636 by 1/3. Input to the input terminal. The adder 6372a calculates a current difference E4a obtained by subtracting the current value IcapA from the current command value IcapA *, and outputs it to the VcapA * generator 6371a. Similarly, the adding unit 6372b calculates a current difference E4b obtained by subtracting the current value IcapB from the current command value IcapA *, and outputs it to the VcapB * generating unit 6371b. Further, the adding unit 6372c calculates a current difference E4c obtained by subtracting the current value IcapC from the current command value IcapA *, and outputs it to the VcapC * generating unit 6371c. The VcapA * generating unit 6371a, the VcapB * generating unit 6371b, and the VcapC * generating unit 6371c are controlled by the same control as the Vcap * generating unit 6371 described in the first embodiment, and each voltage command value VcapA * for the power storage device 61 is controlled. , VcapB * and VcapC * are generated and output to the control signal generator 638 in the next stage.

As shown in FIG. 25, the control signal generation unit 638 has the voltage command value VcapA * in the normalization unit 6381a, the voltage command value VcapB * in the normalization unit 6381b, and the voltage command value VcapC * in the normalization unit 6381c. Entered. Each of the normalization units 6381a, 6381b, and 6381c performs the same operation as that of the normalization unit 6381 described in the first embodiment, and outputs normalization signals NolA, NolB, and NolC, respectively.
Similarly to the case described in the first embodiment, the comparator 6383a compares the normalized signal NolA with the triangular wave signal TriA output from the triangular wave generation unit 6382a, and the state “1” when NolA ≧ TriA. In the case of NolA <TriA, the signal PWMa in the state “0” is output to the dead time generation unit 6384a.
Similarly, the comparator 6383b compares the normalized signal NolB with the triangular wave signal TriB output from the triangular wave generation unit 6382b, and outputs the signal PWMb to the dead time generation unit 6384b. However, this triangular wave signal TriB has the same amplitude and frequency as the triangular wave signal TriA, except that the phase is 1/3 of the period, that is, 120 ° behind.
Similarly, the comparator 6383c compares the normalized signal NolC with the triangular wave signal TriC output from the triangular wave generation unit 6382c, and outputs the signal PWMc to the dead time generation unit 6384c. However, this triangular wave signal TriC has the same amplitude and frequency except that the phase is 2/3 of the period, that is, 240 ° behind the triangular wave signal TriA.

  The dead time generation unit 6384a receives the signal PWMa and the time width Td as inputs, and outputs the control signals SWPa and SWNa by performing the same operation as the dead time generation unit 6384 described in the first embodiment. Similarly, the dead time generation unit 6384b receives the signal PWMb and the time width Td and outputs control signals SWPb and SWNb. The dead time generation unit 6384c receives the signal PWMc and the time width Td and outputs control signals SWPc and SWNc.

  By configuring the AC motor drive device as in the fourth embodiment, it becomes possible to suppress the peak power amount during power running and the peak power amount during regeneration, and the first to third embodiments. As compared with the case of FIG. 5, the current flowing through each of the reactors 623a, 623b, 623c of the chopper circuit 62 is reduced to 1/3, and the phases of the triangular wave signals TriA, TriB, TriC to be compared are 1/3 each. Because of the difference, the ripple current of each of the reactors 623a, 623b, 623c is reduced, and in the control of the AC motor driving device, errors can be reduced and noise generation is reduced. This makes it possible to downsize or omit the additional device. In addition, the size (volume) of each reactor 623a, 623b, 623c can be reduced, the device can be downsized, and the device price can be reduced.

Embodiment 5 FIG.
In the first to fourth embodiments, when the voltage value Vcap across the power storage device 61 is increased or decreased, all control signals such as SWP and SWN always switch the switching elements 621 and 622 to “ It is controlled to repeat the “communication” state and the “disconnection” state.

  In contrast, in the fifth embodiment, the discharging of the power storage device 61 during power running and the charging of the power storage device 61 during regeneration are performed by switching elements 621 (621a to 621c) and 622 constituting the chopper circuit 62. Only one of (622a to 622c) is realized by controlling to repeat the "through" state and the "off" state.

  In the fifth embodiment, the control relationship with the invalidation signal Disable for realizing the “disconnected” state of the switching elements 621 and 622 of the chopper circuit 62 will be described as another form of the second embodiment. However, there is no problem even if this fifth embodiment is adopted as another embodiment of the first, third, and fourth embodiments. In the fifth embodiment, the same numbers are assigned to blocks, circuits or elements having the same or equivalent functions as those in the second embodiment.

A block diagram of the charge / discharge control circuit 63 according to the fifth embodiment is shown in FIG.
The charge / discharge control circuit 63 according to the fifth embodiment is different from the second embodiment in that two signals EnableP and EnableN are output from the adder 636 to the control signal generator 638. Compared with the configuration of the adder 636 of the second embodiment shown in FIG. 14, the adder 636 of the fifth embodiment has three current command values Icap1 *, Icap2 *, Icap3 * as shown in FIG. A gate signal generation unit 6363 is newly added which inputs an integrated current command value Icap * which is the sum of the two and a predetermined threshold value IE and outputs two signals EnableP and EnableN. For convenience of explanation, the threshold value IE is a positive value.

  As shown in FIG. 28, the gate signal generation unit 6363 inputs the integrated current command value Icap * to the “+” terminal of one comparator 63636 and the “−” terminal of the other comparator 63632. . The threshold value IE is input to the “−” terminal of one comparator 63636 and the inverter 63633. The inverter 63633 outputs the value −IE obtained by changing the sign of the threshold IE to the “+” terminal of the other comparator 63632. One comparator 63631 outputs a signal EbleP that is in a “1” state when the integrated current command value Icap * is equal to or greater than the threshold value IE. The comparator 63632 generates a signal EbleN that is in a “1” state when the integrated current command value Icap * is equal to or less than the threshold −IE, and outputs the signal EbableN to the control signal generation unit 638.

  Although the overall configuration of the control signal generation unit 638 in the fifth embodiment is basically the same as that shown in FIG. 17, the difference from the second embodiment is that the dead time generation unit 6384 has a new configuration. That is, two signals EnableP and EnableN are input.

In the dead time generation unit 6384, as shown in FIG. 29, with respect to the control signal SWP described in the first to fourth embodiments, a signal DisableC obtained by inverting one enable signal EnableP and the invalidation signal Disable with a NOT element 63848 A new control signal SWP gated using a three-input AND element 63849 is generated with both of the signals. That is, when the integrated current command value Icap * has a large value out of the range of (Equation 10) described above, the invalidation signal Disable is “0”, and the permission signal EnableP is “1”, One control signal SWP is output.
Similarly, with respect to the control signal SWN described in the first to fourth embodiments, a new control signal SWN gated using the three-input AND element 63850 is generated by using both the other enable signal EnableN and the signal DisableC. . That is, when the integrated current command value Icap * has a large value out of the range of (Equation 10) described above, the invalidation signal Disable is “0”, and the permission signal EnableN is “1”, The other control signal SWN is output.

  Thus, when the power storage device 61 is charged during regeneration, only the switching element 621 connected to the high-voltage side DC bus 3a is controlled to repeat the “ON” state and the “OFF” state by one control signal SWP. Thus, the switching element 622 connected to the low-voltage side DC bus 3b is always controlled to the “OFF” state by the other control signal SWN. On the other hand, when discharging the power storage device 61 during power running, the switching element 621 connected to the high-voltage side DC bus 3a is always controlled to the “OFF” state by one control signal SWP, and the other control signal SWN Thus, only the switching element 622 connected to the low-voltage side DC bus 3b is controlled to repeat the “through” state and the “off” state.

When the fifth embodiment is applied to the fourth embodiment, that is, when the chopper circuit 62 has three phases, one enable signal EnableP gates the control signals SWPa, SWPb, SWPc, and the other The permission signal EnableN gates the control signals SWNa, SWNb, and SWNc. It is obvious that the configuration of the fifth embodiment is used even when the chopper circuit 62 is other than a single phase or three phases.
Since other configurations and operations are the same as those in the second embodiment, detailed description thereof is omitted here.

  By configuring the AC motor drive device as in the fifth embodiment, it becomes possible to suppress the peak power amount during power running and the peak power amount during regeneration, and the switching element 621 in the chopper circuit 62, It is also possible to avoid short-circuiting of the DC bus 3 irrespective of the difference between the transition time from the “communication” state 622 to the “disconnection” state and the transition time from the “disconnection” state to the “communication” state. In addition, one of the switching element 621 in the chopper circuit 62 connected to the high-voltage side DC bus 3a and the switching element 622 in the chopper circuit 62 connected to the low-voltage side DC bus 3b continues to be in the “OFF” state. Therefore, the generation of noise can be reduced, and the additional device for noise countermeasure can be downsized or omitted.

  When the threshold value IΔ and the threshold value IE are the same value, a signal obtained by inverting D1 that is the output of the comparator 63611 in the small command value determination unit 6361 is set as one permission signal EnableP, There is also a method in which a signal obtained by inverting D2 that is the output of the comparator 63612 in the command value determination unit 6361 is set as the other permission signal EnableN, and the gate signal generation unit 6363 is omitted. With this configuration, the circuit scale can be reduced and the device price can be reduced.

Embodiment 6 FIG.
The feature of the sixth embodiment is that when a large amount of power is regenerated at the start of the regenerative operation, the current command value Icap2 * generated in the regenerative power compensation unit 634 is realized by PI control or the like. The fact that it can only be gradually changed by an integration factor has been improved so that it can effectively cope with a phenomenon in which a steep regenerative power peak occurs in the power Pcnv on the output side of the converter 2.

  In general, in discrete system PI control, the output y (kT) at time kT with respect to the input e (it) is expressed as follows when the proportional gain is Kp, the integration time is Ti, and the period of the discrete system is D: 12).

FIG. 30 shows details when the Icap2 * generation unit 6341 constituting the regenerative power compensation unit 634 (see FIG. 6) in the first embodiment is realized by PI control.
The Icap2 * generation unit 6341 performs PI control according to the above (Equation 12), and the proportional gain multiplier 63411 supplies the signal E2p obtained by multiplying the power difference E2 by Kp to the integral gain multiplier 63412 and the adder 63415, respectively. The integral gain multiplier 63412 outputs to the adder 63414 a signal E2i obtained by multiplying the signal E2p by (D / Ti). The adder 63414 generates a signal E2q obtained by adding the signal E2i and a signal E2d which is an output of a delay circuit 63413 described later, and outputs the signal E2q to the delay circuit 63413 and the adder 63415. The delay circuit 63413 generates a signal E2d obtained by delaying the signal E2q by time D. Adder 63415 calculates the sum of both signals E2p and E2q and outputs the result as current command value Icap2 *.

  By the way, the regenerative operation in the AC motor drive device is large at the start of the regenerative operation, as shown in FIG. Electricity is often regenerated. Now, assuming that the regeneration power compensation threshold LPL is the amount of power indicated by the alternate long and short dash line in FIG. 31 (a), the desired amount of charge to be charged by the power storage device 61 is as shown in FIG. 31 (b). . If this desired charging power amount is ensured, the power difference E2 defined by (Equation 2) described above continues with a small negative value as shown in FIG. 31 (c).

  However, if the Icap2 * generation unit 6341 in the regenerative power compensation unit 634 is configured to perform the PI control as shown in FIG. 30, the current command value Icap2 * is shown in FIG. 31 (d). As shown, it gradually increases from the start of the regenerative operation (time T5), decreases from a certain time after the time when the desired charge power amount is secured (time T ', not shown), and the desired charge power amount disappears. After that (time T6), it returns to “0” and ends the power compensation operation. In the period (between times T ′ and T6) in which the current command value Icap2 * gradually increases, the amount of power that is actually charged in the power storage device 61 is, as shown in FIG. The amount is not reached. For this reason, as indicated by diagonal lines in FIG. 31 (f), a large amount of regenerative power exceeding the regenerative power compensation threshold LPL is regenerated to the converter 2 and returned to the system power source 1, or heat is generated in the converter 2. It is converted into energy and released. That is, the regenerative electric power is not charged into the power storage device 61 and waste occurs.

  Therefore, in the sixth embodiment, the regenerative power compensation unit 634 can suppress the regenerative power amount at the start of the regenerative operation. That is, as shown in FIG. 32, the regenerative power compensation unit 634 in the sixth embodiment has a comparator 6342 when compared with the configuration of the regenerative power compensation unit 634 (see FIG. 6) in the first embodiment. The regeneration power compensation threshold value LPL is input to the “+” terminal of the comparator 6342 and the power Pcnv on the output side of the converter 2 is input to the “−” terminal. Therefore, when this power Pcnv exceeds the power compensation threshold value LPL during regeneration, that is, when the value of the power Pcnv becomes smaller than the power compensation threshold value LPL during regeneration, the state of “1” is obtained. A determination signal s is output. The determination signal s is output to the Icap2 * generation unit 6341 at the next stage.

  Next, FIG. 33 shows the configuration of the Icap2 * generation unit 6341 according to the sixth embodiment. Here, the proportional gain multiplier 63411, the integral gain multiplier 63411, the delay circuit 63413, the adder 63414, and the adder 63415 constituting the Icap2 * generation unit 6341 have the same functions as those of the same reference numerals in FIG. is there.

The signal E2p output from the proportional gain multiplier 63411 is supplied to the integral gain multiplier 63412 and the adder 63415, respectively. The signal E2i output from the integral gain multiplier 63412 is output to the adder 63414. The adder 63414 generates a signal E2q obtained by adding the signal E2i and the signal E2d output from the delay circuit 63413, and outputs the signal E2q to the limiter 63417. The limiter 63417 outputs “0” when the input signal E2q is less than “0”, and outputs the value of Icap_max when the input signal E2q is larger than a predetermined threshold value Icap_max. When the signal E2q is not less than “0” and not more than the threshold value Icap_max, the value of the input signal E2q is output as it is.
In this case, the threshold value Icap_max is set to a value equal to or smaller than the allowable current amount of the reactor 623 of the chopper circuit 62. Further, as shown in the fourth embodiment, in the case of a multiplexed chopper circuit, the threshold value Icap_max is set to a value equal to or less than the sum of the allowable current amounts of the reactors in the chopper circuit 62. In this way, the output of the limiter 63417 subjected to amplitude limitation is set as a signal E2r. This signal E2r is output to one input terminal of the switch 63416. The switch 63416 switches between two inputs according to the state of the determination signal s output from the comparator 6342 and outputs only one input as the signal E2s. A predetermined regenerative current command value integral component initial value Icap2i is input to the other input terminal of the switch 63416.
The switch 63416 outputs the signal E2r when the determination signal s is “0”, and conversely, when the determination signal s is “1”, the regenerative current command value integral component initial stage is output. The value Icap2i is output. The signal E2s that is the output of the switch 63416 is output to the delay circuit 63413 and the adder 63415, respectively. The delay circuit 63413 generates a signal E2d obtained by delaying the input signal E2s by a predetermined time D. The adder 63415 calculates the sum of the signal E2p and the signal E2s, and outputs the sum to the limiter 63418 as the signal E2t. The limiter 63418 has the same function as the limiter 63417, and outputs the input signal E2t as a current command value Icap2 *.

  Next, the operation of the Icap2 * generation unit 6341 illustrated in FIG. 33 will be described with reference to FIG. Note that FIGS. 34 (a), (b), and (c) have the same waveforms as FIGS. 31 (a), (b), and (c), and thus the description thereof is omitted here.

  At time T5 in FIG. 34, which is the start time of the regenerative operation, the value of the electric power Pcnv on the output side of the converter 2 is smaller than the regenerative power compensation threshold LPL, so that the determination signal s is “ The state changes from “0” to “1”. Therefore, the signal E2s output from the switch 63416 in FIG. 33 outputs the regenerative current command value integral component initial value Icap2i. The signal E2s from which the regenerative current command value integral component initial value Icap2i is output is added to the signal E2p output from the proportional gain multiplier 63411 in the adder 63415, and the current command value Icap2 * is passed through the limiter 63418. Is output. Further, the signal E2s from which the regenerative current command value integral component initial value Icap2i is output is input to the adder 63414 via the delay circuit 63413 in FIG. 33, and is added to the signal E2i output from the integral gain multiplier 63412. .

  By setting the regenerative current command value integral component initial value Icap2i to a value close to the threshold value Icap_max defined in advance for each of the limiters 63417 and 63418, the current command value integral component initial value Icap2i is immediately regenerated at time T5. Based on the changed current command value Icap2 *, as shown in FIG. 34 (f), the amount of power that is actually charged in the power storage device 61 increases rapidly at time T5, and a sufficient amount of regenerative power is secured. be able to. With this operation, the amount of regenerative power exceeding the regenerative power compensation threshold LPL can be significantly suppressed as shown in FIG. 34 (g).

  Thus, when a sufficient amount of regenerative power is ensured in the power storage device 61, the power Pcnv on the output side of the converter 2 becomes a value larger than the regenerative power compensation threshold LPL (a smaller value in comparison with the absolute value). As shown in FIG. 34 (d), the determination signal s returns from the “1” state to the “0” state, and the switch 63416 shown in FIG. 33 selects and outputs the input E2r. Then, due to the current command value Icap2 * shown in FIG. 34 (e), the electric power Pcnv becomes a value smaller than the regenerative power compensation threshold LPL (a large value in the absolute value comparison), so the determination signal s is “0” again. The state changes from “1” to “1”.

  In this manner, during the period when the load Pload exceeds the regeneration power compensation threshold LPL (between time T5 and time T6 in FIG. 34A), the switch 63416 shown in FIG. 33 is in the “1” state and “0”. If the load Pload does not exceed the regenerative power compensation threshold LPL while continuing the above state, the discrimination signal s continues to be in the “0” state, and the regenerative operation is terminated.

  By configuring the AC motor drive device as in the sixth embodiment, it becomes possible to suppress the peak power amount during power running and the peak power amount during regeneration, and also steep regenerative power at the start of regeneration operation. It is possible to suppress the regenerative power amount to the converter 2 below the regenerative power compensation threshold value LPL even when the amount changes, and a large regenerative power amount exceeding the regenerative power compensation threshold value LPL is supplied to the converter 2. Regenerative power is not charged into the power storage device 61 and is wasted, such as being regenerated and returned to the system power supply 1 or converted into thermal energy in the converter 2 and released.

Embodiment 7 FIG.
On the output side of the converter 2, there is a smoothing capacitor (not shown) for stabilizing the DC bus voltage value Vdc, although the capacitance is smaller than that of the power storage device 61. When the AC motor drive device does not perform a power running operation or a regenerative operation, that is, a DC bus voltage value in a no-load state is expressed as Vdc0 in particular. Even if the charging / discharging process of the power storage device 61 is performed, the DC bus voltage value Vdc when the AC motor driving device is in the power running operation is held at a value lower than Vdc0 due to the delay of control and the responsiveness of the power storage device 61. The DC bus voltage value Vdc when the AC motor driving device is in the regenerative operation is held at a value higher than Vdc0.

  The converter 2 is preset with a predetermined threshold value VΔ from the viewpoint of its own circuit protection. When the DC bus voltage value Vdc reaches Vdc0 + VΔ during the regeneration operation of the AC motor driving device, the converter 2 The regenerative power is returned to the system power source 1 or converted into thermal energy by a resistor built in the converter 2 and released. Therefore, if the charging operation of power storage device 61 is not started before the time when DC bus voltage value Vdc is increased to Vdc0 + VΔ during regeneration, regenerative power is regenerated to converter 2 in vain. However, as described above, since the capacitance of the smoothing capacitor of converter 2 is small, DC bus voltage value Vdc may reach Vdc0 + VΔ within a relatively short time.

  Therefore, in the seventh embodiment, immediately before the regenerative operation of the AC motor driving device (that is, in the case of E1 ≦ 0 or E2 ≧ 0), the electric power is stored by the current command value Icap3 * that is the output of the auxiliary charging control unit 635. By setting the device 61 to a charged state, the DC bus voltage value Vdc is forcibly held at a value lower than Vdc0, and the time until the DC bus voltage value Vdc at the start of the regenerative operation of the AC motor driving device reaches Vdc0 + VΔ is determined. By increasing the length, the peak power at the start of the regenerative operation can be surely suppressed. Hereinafter, a specific example of the seventh embodiment will be described.

  An example will be described in which the load Pload (= Pcnv−Pcap) calculated by the auxiliary charge control unit 635 is indicated by a solid line in FIG. FIG. 35 (a) is the same as FIG. 12 (a). Now, in FIG. 35 (a), the time when the waveform starts is T0, the power running start time is T1, the time when the load Pload exceeds the power running auxiliary charge control unit operation threshold LSU, and the time when the load Pload is the power running power compensation threshold. The time exceeding the LPU is T3, and the power running end time is T4. The regenerative operation start time is T5. The period during which auxiliary charge control unit 635 operates is between time T0 and time T2 and between time T4 and time T5 in FIG.

  Next, in Icap3 * generation unit 6351 in auxiliary charge control unit 635, the operation will be described separately for the case where the gain with respect to voltage difference E3 is large and the case where the gain is small.

  First, the case where the gain is large will be described with reference to FIGS. 35 (b), (c), and (d).

  During the power running operation, the power storage device 61 is discharged during the period from time T4 to time T5, and thus the voltage value Vcap across the power storage device 61 does not change during the period from time T0 to time T3. Therefore, the current command value Icap3 * for performing charge / discharge control for stabilizing the voltage of the power storage device 61 remains “0” during the period from time T0 to time T3. Further, as described in the first embodiment, the Icap3 * generation unit 6351 is configured to generate a current command only when the load Pload is between the power running auxiliary charge control unit operation threshold value LSU and the regeneration auxiliary charge control unit operation threshold value LSL. Since the value Icap3 * is output, the output of “0” remains during the period from time T2 to time T4. Therefore, the current command value Icap3 * remains “0” during the period from time T0 to time T4. On the other hand, during the period from time T1 to time T3, there is no discharge from the power storage device 61, and the amount of power supplied from the system power supply 1 by the converter 2 is delayed. For this reason, as shown in FIG. 35D, the DC bus voltage value Vdc continues to decrease. In the period from time T3 to time T4, the current command value Icap1 * is output from the power running time power compensation unit 633. Therefore, as shown in FIG. As shown in FIG. 35D, the DC bus voltage value Vdc is kept constant while the value Vcap is lowered. When the power running operation ends at time T4, the Icap3 * generation unit 6351 starts to operate, and, as shown in FIG. 35B, outputs a positive current command value Icap3 *. Charging of the electricity storage device 61 is started. At this time, since the gain of the Icap3 * generation unit 6351 is large, the current command value Icap3 * outputs a large value (Icap3 * a), and the power storage device 61 is charged rapidly. The both-end voltage value Vcap of the electricity storage device 61 rises as shown in FIG. 35C by the charging process, and the both-end voltage value Vcap recovers to the desired voltage value VcapTH at time TA. During the period from time T4 to time TA, the DC bus voltage value Vdc changes at a value lower than Vcap0, although not as much as during powering operation. When the voltage Vcap across the storage device 61 recovers to the desired voltage value VcapTH, the Icap3 * generation unit 6351 stops operating, the current command value Icap3 * becomes “0” again, and the DC bus voltage value Vdc also returns to Vdc0. And waits for the regeneration operation start time T5 to arrive. At the regenerative operation start time T5, the DC bus voltage value Vdc immediately rises from Vdc0 and reaches Vdc0 + VΔ due to the influence of control delay and the responsiveness of the power storage device 61. Details of the operation at the regenerative operation start time T5 will be described later.

  Next, a case where the gain for the voltage difference E3 is small in the Icap3 * generation unit 6351 in the auxiliary charge control unit 635 will be described with reference to FIGS. 35 (e), (f), and (g).

During the period from time T0 to time T4, the current command value Icap3 * remains “0” for the same reason as described above when the gain of the Icap3 * generation unit 6351 is large. Similarly, during the period from time T0 to time T4, as shown in FIGS. 35 (f) and 35 (g), the both-end voltage Vcap and the DC bus voltage value Vdc of the power storage device 61 are both the Icap3 * generation unit 6351 described above. The waveform is the same as when the gain is large.
However, when the power running operation ends at time T4 and the Icap3 * generation unit 6351 starts to operate, the auxiliary charging control unit 635 outputs a positive current command value Icap3 * and starts charging the power storage device 61. However, since the gain of the Icap3 * generating unit 6351 is small at this time, the current command value Icap3 * outputs only a small value (Icap3 * b) as shown in FIG. 35 (e), and FIG. As shown, the both-end voltage value Vcap of the electricity storage device 61 increases only little by little, and does not recover to the desired voltage value VcapTH by the regeneration operation start time T5. During the period from time T4 to time T5, the state of charge of the power storage device 61 always continues, so the DC bus voltage value Vdc continues to be lower than Vdc0 and reaches the regenerative operation start time T5. At the regenerative operation start time T5, the DC bus voltage value Vdc immediately rises due to the delay in control and the responsiveness of the power storage device 61. However, since the rise start voltage value is a voltage value lower than Vdc0, It takes a while until the voltage value Vdc reaches Vdc0 + VΔ.

  Next, when the DC bus voltage value Vdc does not return to Vdc0 at the regeneration operation start time T5 (in the case of FIG. 35G), that is, when the gain of the Icap3 * generation unit 6351 is small, the regeneration operation start time FIG. 36 shows that the peak power of the regenerative power can be suppressed when the DC bus voltage value Vdc returns to Vdc0 at T5 (in the case of FIG. 35D), that is, when the gain of the Icap3 * generation unit 6351 is large. It explains using.

FIG. 36 is an enlarged view of the waveform near the regeneration operation start time T5 of FIG. 35 in the time axis direction.
As shown in FIG. 36 (a), the peak value during load Pload regeneration (see FIG. 35 (a)) is Pload_min (<0). Further, it is assumed that the current command value Icap2 * for charging control of the power storage device 61 starts to increase from time T52 due to control delay and reaches a steady value at time T54 as shown in FIG. FIGS. 36C and 36D respectively show the behaviors of the DC bus voltage Vdc and the power Pcnv on the output side of the converter 2 when the DC bus voltage value Vdc returns to Vdc0 at the regeneration operation start time T5. 36 (e) and 36 (f) show the behavior of the DC bus voltage Vdc and the power Pcnv on the output side of the converter 2 when the DC bus voltage value Vdc does not return to Vdc0 at the regeneration operation start time T5, respectively. Represents each.

  When the DC bus voltage value Vdc returns to Vdc0 at the regenerative operation start time T5, the regenerative power flows into the smoothing capacitor and the DC bus voltage value Vdc rises from Vdc0, so that the DC bus voltage value Vdc reaches Vdc0 + VΔ. As shown in FIG. 36 (c), time T51 arrives in a period (between time T5 and time T52) in which the current command value Icap2 * for charging control of the power storage device 61 is not yet output. After the DC bus voltage value Vdc reaches Vdc0 + VΔ, the converter 2 starts to regenerate power. Therefore, as shown in FIG. 36 (d), the power Pcnv starts to regenerate from time T51. However, since the current command value Icap2 * has not yet instructed the power storage device 61 to charge during the period from time T51 to time T52, as shown in FIG. 36 (d), all the regenerative power from the AC motor 5 is converted to the converter. 2, the power Pcnv on the output side of the converter 2 reaches the peak value Pload_min. After time T52, charging of power storage device 61 is started in accordance with the charging instruction of current command value Icap2 *, so that the amount of power supplied to converter 2 decreases, and power Pcnv is regenerated power compensation threshold LPL at time T54. To settle down.

  On the other hand, when the DC bus voltage value Vdc does not return to Vdc0 at the regenerative operation start time T5, the regenerative power flows into the smoothing capacitor and increases the DC bus voltage value Vdc, but the DC bus voltage value Vdc is higher than Vdc0. The time T53 when the DC bus voltage value Vdc reaches Vdc0 + VΔ because it rises from a low voltage value is between time T52 and time T54, that is, the current for charging control of the power storage device 61, as shown in FIG. It is after the output of the command value Icap2 * has already started. Since converter 2 starts to regenerate power after DC bus voltage value Vdc reaches Vdc0 + VΔ, as shown in FIG. 36 (f), power Pcnv starts to regenerate from time T53. However, since the current command value Icap2 * has already instructed the power storage device 61 to charge at time T53, the power Pcnv does not reach Pload_min, and the regenerative power at time T54 is in accordance with the charging instruction of the current command value Icap2 *. The compensation threshold LPL is settled.

Therefore, the peak power at the start of the regenerative operation is set by setting the gain of the Icap3 * generating unit 6351 to an appropriate value so that the operations shown in FIGS. 36 (e) and (f) are executed. Suppression can be realized reliably.
Thus, by configuring the AC motor drive device as in the seventh embodiment, it becomes possible to suppress the peak power amount during power running and the peak power amount during regeneration, and at the time of starting the regenerative operation. It becomes possible to reliably suppress the peak power.

Embodiment 8 FIG.
Power running power compensation threshold LPU, regeneration power compensation threshold LPL, desired voltage value VcapTH, power running auxiliary charge control unit operation threshold LSU, regeneration auxiliary charge control unit operation threshold LSL described in the first to seventh embodiments. Dead time Td, and further, Icap_max corresponding to the maximum value of IΔ, IE, VΔ, TΔ, current command value, current command value integration component initial value Icap2i during regeneration, Icap1 * generating unit 6331, Icap2 * generating unit 6341, Icap3 * Values related to the gains of the generation unit 6351 and the Vcap * generation unit 6371 are values to be determined by the load power amount of the AC motor 5, the capacitance of the power storage device 61, the internal resistance, the inductance of the reactor 623, the saturation current amount, and the like. These values are set to appropriate values according to the usage environment of the AC motor drive device. Since it should be determined, it is not decided in advance, but part or all of these values are set by the user of the AC motor driving device each time via buttons, switches or serial communication. It is preferable.

Embodiment 9 FIG.
The case where the charge / discharge control circuit 63 in each of the first to eighth embodiments is realized by hardware has been described. The charge / discharge control circuit 63 receives, as an input, a DC bus voltage value Vdc, a DC bus current value Idc on the output side of the converter 2, a voltage value Vcap across the storage device 61, and a charge / discharge current value Icap of the storage device 61. Output control signals SWP (SWPa to SWPc) and SWN (SWNa to SWNc) for controlling the switching elements 621 (621a to 621c) and 622 (622a to 622c) into two states, a “ON” state and a “OFF” state. Therefore, part or all of the charge / discharge control circuit 63 can be realized by software. Here, the case where it applies to Embodiment 1 is demonstrated. The same number is assigned to a block having the same or equivalent function as in the first embodiment.

  FIG. 37 is a block diagram of an AC motor driving device when the entire charge / discharge control circuit 63 is configured by software, and FIG. 38 is a block diagram of the power storage circuit 6.

  In FIG. 37, an analog / digital converter (A / D converter) 7 converts a DC bus voltage value Vdc into a digital value and outputs it to the storage circuit 6, and an A / D converter 8 is the output side of the converter 2. The DC bus current value Idc is converted to a digital value and output to the storage circuit 6. Other parts in FIG. 37 are the same as those in the first embodiment (FIG. 1).

  In FIG. 38, the A / D converter 64 converts the voltage value Vcap at both ends of the power storage device 61 into a digital value and outputs the digital value to the charge / discharge control circuit 63. The discharge current value Icap is converted into a digital value and output to the charge / discharge control circuit 63. The control signals SWP and SWN are converted into voltage amplitudes and current amounts that can drive the switching elements 621 and 622 in the chopper circuit 62 in the drivers 66 and 67 and output to the chopper circuit 62. Other parts of FIG. 38 are the same as those of the embodiment (FIG. 2).

  Next, a procedure in the case where the entire charge / discharge control circuit 63 is configured by software will be described with reference to FIG.

First, in step S10, the threshold value or current command described in the eighth embodiment is determined by the load power amount, the capacitance or internal resistance of the power storage device 61, the inductance of the reactor 623 in the chopper circuit 62, the saturation current amount, or the like. Values relating to a value generation gain and a voltage command value generation gain are input and stored in a storage element such as a register.
Next, in step S11, the digitized DC bus voltage value Vdc shown in FIG. 37 and the digitized DC bus current value Idc on the output side of converter 2 are input, and in step S12, the output side of converter 2 is output. Electric power Pcnv (= Vdc × Idc) is calculated.
In step S13, the power Pcnv is compared with the power running power compensation threshold LPU and the regeneration power compensation threshold LPL. When the power Pcnv is larger than the power running power compensation threshold LPU, the process proceeds to step S14 described later. On the other hand, if the power Pcnv is smaller than the regeneration power compensation threshold LPL in step S13, the process proceeds to step S15 described later. In step S13, when the power amount Pcnv is equal to or greater than the regeneration power compensation threshold LPL and equal to or less than the power running power compensation threshold LPU, the process proceeds to step S16 described later.
In step S14, processing similar to that of the power running power compensation unit 633 described in the first to seventh embodiments is performed to calculate a current command value Icap1 * for discharging control of the power storage device 61, which will be described later. The process proceeds to S20. In step S15, a process similar to that of regenerative power compensation unit 634 described in the first to seventh embodiments is executed, a current command value Icap2 * for charge control is calculated, and the process proceeds to step S20 described later. .
In step S16, the digitized voltage value Vcap and the input / output current Icap of the digitized power storage device 61 shown in FIG. 38 are input. In step S17, the input / output power Pcap (= Vcap × Icap) is calculated, The load Pload (= Pcnv−Pcap) is calculated from the output power Pcap and the power Pcnv calculated in step S11, and the process proceeds to step S18.
In step S18, when the load amount Pload is larger than the regeneration auxiliary charge control unit operation threshold value LSL and smaller than the power running auxiliary charge control unit operation threshold value LSU, the process proceeds to step S19 described later. Return to S11.
In step S19, processing similar to that of the auxiliary charging control unit 635 described in the first to seventh embodiments is executed to calculate the current command value Icap3 * of the power storage device 61, and the process proceeds to step S20 described later.
In step S20, from the current command value Icap1 * calculated in step S14, the current command value Icap2 * calculated in step S15, and the current command value Icap3 * calculated in step S19, the above-described first to seventh embodiments are performed. The integrated current command value Icap * is generated by executing the same processing as that of the adding unit 636 described. In step S20, if necessary, the invalidation signal Disable and the enable signals EnableP and EnableN described in the second embodiment or the fifth embodiment are also generated, and the process proceeds to step S21.
In step S21, processing similar to that of voltage command value generation unit 637 described in the first to seventh embodiments is executed to calculate voltage command value Vcap *, and the process proceeds to step S22 described later.
In step S22, processing similar to that of the control signal generation unit 638 described in the first to sixth embodiments is performed to generate the control signals SWP and SWN, and the drivers 66 and 67 shown in FIG. The process proceeds to the next step S23.
In step S23, it is determined whether or not a series of operations of the AC motor drive device has been completed. If not completed, the process returns to the above-described step S11, and if completed, the operation of the AC motor drive circuit is terminated as it is. .

1 system power supply, 2 converter, 3 DC bus, 4 inverter, 5 AC motor,
6 power storage circuit, 61 power storage device, 62 chopper circuit, 63 charge / discharge control circuit,
633 Power running compensation unit, 634 regeneration power compensation unit, 635 auxiliary charge control unit,
637 Voltage command value generation part, 638 Control signal generation part.

Claims (4)

A converter that converts AC power into DC power, an inverter that converts the DC power obtained by the converter into AC power having a voltage and frequency suitable for an AC motor, and supplies the AC power to the AC motor, and is connected in parallel to the inverter. During the power running operation of the AC motor, a part of the power running power is assisted by the discharging operation of the power storage device provided therein, and during the regenerative operation of the AC motor, a part of the regenerative power is stored by the charging operation of the power storage device. An AC motor driving device comprising:
The power storage circuit is
A current command value for discharging the power storage device based on a voltage value and a current value of DC power on the output side of the converter when a powering power larger than a preset first threshold is used in the AC motor. A power running power compensation unit for generating
When regenerative power having an absolute value larger than a preset second threshold value is regenerated from the AC motor, a current command for charging the power storage device based on the voltage value and current value of DC power on the output side of the converter A regenerative power compensator for generating a value;
The power storage device based on a voltage value and a current value of DC power on the output side of the converter, a voltage value between both ends of the power storage device, and an input / output current value within a preset third threshold value and a fourth threshold value. An auxiliary charge control unit for generating a current command value for charging / discharging the power storage device in order to set a voltage value at both ends of the battery to a predetermined voltage value;
Including
The absolute value of the third threshold value is smaller than the absolute value of the first threshold value, and the absolute value of the fourth threshold value is smaller than the absolute value of the second threshold value. AC motor driving device for. When the regenerative power having a larger absolute value than the second threshold value is regenerated from the AC motor, the regenerative power compensation unit is not initially set to “0” that is preset as the current command value each time. The AC motor driving apparatus according to claim 1, wherein a value is used . The AC motor driving apparatus according to claim 2 , wherein the regeneration power compensation unit uses a preset initial value other than "0" as an initial value of an integral component of the current command value for charging the power storage device . After the power running power becomes equal to or less than the first threshold value and before the time when the absolute value of the regenerative power becomes larger than the second threshold value, the auxiliary charge control unit is configured to charge the power storage device. The AC motor driving apparatus according to any one of claims 1 to 3, wherein the command value is generated .

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