WO2016063724A1 - Three-phase neutral point clamped power conversion device - Google Patents

Three-phase neutral point clamped power conversion device Download PDF

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Publication number
WO2016063724A1
WO2016063724A1 PCT/JP2015/078447 JP2015078447W WO2016063724A1 WO 2016063724 A1 WO2016063724 A1 WO 2016063724A1 JP 2015078447 W JP2015078447 W JP 2015078447W WO 2016063724 A1 WO2016063724 A1 WO 2016063724A1
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Prior art keywords
phase
command value
neutral point
voltage command
value
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PCT/JP2015/078447
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French (fr)
Japanese (ja)
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賢司 小堀
鎮教 濱田
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株式会社明電舎
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/483—Converters with outputs that each can have more than two voltages levels
    • H02M7/487—Neutral point clamped inverters

Definitions

  • the present invention relates to a three-phase neutral point clamp type multi-level power converter, and more particularly to neutral point voltage control using PWM control.
  • FIG. 7 is a configuration diagram showing a main circuit in a three-phase neutral point clamp type power converter connected to a motor load.
  • the switching devices IGBT in FIG. 7
  • the switching devices S1 to S12 are turned ON / OFF, and an AC voltage is output to the output terminals U, V, and W.
  • This power converter divides the DC voltage PN between the smoothing capacitors Cdc1 and Cdc2, and outputs three-level potentials of the DC potentials P and N and the neutral point potential NP using PWM modulation (Pulse Width Modulation). Is.
  • neutral point potential control (Neutral Point Control) is performed to suppress variations in DC voltages Vdc1 and Vdc2.
  • the neutral point potential control takes a deviation between the DC voltage Vdc1 of the smoothing capacitor Cdc1 on the positive electrode side (P side) between the DC voltages PN and the DC voltage Vdc2 of the smoothing capacitor Cdc2 on the negative electrode side (N side). Is controlled so that becomes zero.
  • FIG. 8 is a block diagram showing a control circuit of a three-phase neutral point clamp type power converter.
  • the phase detector enc is attached to the motor M, and the phase detection value is theta_det.
  • three-phase currents (motor currents) Iu, Iv, and Iw are three-phase to two-phase converted based on the phase detection value theta_det, and a d-axis current detection value Id_det and a q-axis current detection value Iq_det are obtained. obtain.
  • the d-axis current command value Id_cmd and the q-axis current command value Iq_cmd are set as target values, and PI control is performed so that the d-axis current detection values Id_det and Iq_det follow the target values.
  • the output of the current control unit ACR becomes the two-phase voltage command values Vd_cmd and Vq_cmd.
  • the two-phase voltage command values Vd_cmd and Vq_cmd are subjected to two-phase / three-phase conversion by the two-phase / three-phase converter 2 to generate a three-phase voltage command value V_cmd.
  • the neutral point potential control unit NPC calculates a neutral point potential compensation amount V_cmp based on the DC voltages Vdc1 and Vdc2.
  • the neutral point potential compensation amount V_cmp is added to the three-phase voltage command value V_cmd, and the voltage command after the addition is set as a correction voltage command value V_cmd ′.
  • the correction voltage command value V_cmd ′ is limited by the limiter LMT, and the limit processing voltage command value V_cmd ′′ is input to the PWM processing unit PWM.
  • the limiter LMT outputs the correction voltage command value as it is as the limit processing voltage command value V_cmd ′′ when the correction voltage command value V_cmd ′ is below the threshold value, and sets the threshold value when the correction voltage command value V_cmd ′ is equal to or greater than the threshold value. Output as limit processing voltage command value V_cmd ′′.
  • the purpose of providing the limiter LMT is to prevent the gate commands GI_H and GI_L, which will be described later, from becoming abnormal pulses (minimum pulses, etc.) and to prevent distortion in the output voltage and output current of the power converter. .
  • the PWM processing unit PWM generates the gate commands GI_H and GI_L of the switching devices S1 to S12 using the limit processing voltage command value Vcmd ′′.
  • a method of generating the gate commands GI_H and GI_L by comparing the triangular wave carrier signal and the limit processing voltage command value V_cmd ′′ is general.
  • the corrected voltage command value V_cmp ′ is a value obtained by adding the neutral point potential compensation amount V_cmp to the three-phase voltage command value V_cmd.
  • a large output current of the power converter that is, motor current
  • the output of the current control unit ACR is two-phase.
  • the three-phase voltage command value V_cmd after the three-phase conversion also increases.
  • the capacitor capacities of the smoothing capacitors Cdc1 and Cdc2 in FIG. 7 are generally equal, the deviation of the initial charge value, that is, the deviation between the DC voltages Vdc1 and Vdc2 becomes large due to manufacturing variations and aging degradation. That is, the neutral point potential compensation amount V_cmp immediately after startup tends to increase.
  • the gain of the current control or neutral point voltage control is lowered.
  • the steady-state control performance decreases. Therefore, a control mechanism that takes into account the interference between current control and neutral point potential control without reducing the gain of neutral point potential control is required.
  • One aspect of the present invention is a three-phase neutral point clamp type power converter, and its control circuit includes a d-axis current command value and d
  • a current control unit that calculates a two-phase voltage command value by a current control function that performs PI control based on a deviation from the detected shaft current value and a deviation between the q-axis current command value and the q-axis current detected value;
  • a two-phase three-phase conversion unit that converts a phase voltage command value into a three-phase voltage command value, a neutral point potential control unit that calculates a neutral point potential compensation amount that compensates for a voltage deviation of a smoothing capacitor connected in series, Output a value that limits the neutral point potential compensation amount as a limit compensation amount until a preset time has elapsed since the start of operation of the power converter, and after a preset time has elapsed since the start of the operation of the power converter The neutral point potential compensation amount is output as it
  • a limiter that outputs the threshold value as a limit processing voltage command value when the correction voltage command value is equal to or greater than the threshold value, and a PWM control unit that performs PWM control based on the limit treatment voltage command value.
  • the limiting means sets the limit compensation amount to 0 until a preset time elapses after the power converter starts operation.
  • the limiting means sets the limit compensation amount to 0 until the power conversion device starts operation, and the limit compensation amount until a preset time elapses after the power conversion device starts operation. Is gradually increased.
  • the load connected to the three-phase AC output of the power converter is a motor
  • the three-phase current detection value is converted to the d-axis current detection value and the q-axis current detection value based on the phase detection value of the motor
  • the two-phase voltage command value is converted into a three-phase voltage command value based on the phase detection value of the motor.
  • the power conversion device is connected to a grid, and converts a three-phase current detection value into a d-axis current detection value and a q-axis current detection value based on a detection value of the system phase.
  • the two-phase voltage command value is converted into a three-phase voltage command value based on the phase detection value.
  • FIG. 2 is a block diagram illustrating a control circuit according to the first embodiment.
  • FIG. 4 is a block diagram illustrating a control circuit in a second embodiment.
  • 9 is a time chart showing an input / output operation of a variable limiter according to the second embodiment.
  • FIG. 9 is a block diagram illustrating a control circuit according to a third embodiment.
  • FIG. 9 is a block diagram illustrating a control circuit according to a fourth embodiment.
  • the block diagram which shows an example of the conventional control circuit.
  • Embodiments 1 to 4 of the three-phase neutral point clamp type multilevel power conversion device according to the present invention will be described below in detail with reference to FIGS.
  • FIG. 1 is a block diagram illustrating a control circuit of the power conversion device according to the first embodiment.
  • the control circuit of the first embodiment takes into account interference between current control and neutral point potential control.
  • the neutral point potential compensation amount V_cmp output by the neutral point potential control unit NPC is limited until the preset time elapses from the start of operation of the power converter.
  • the delay is limited by the delay counter 4).
  • the delay counter 4 is triggered by a signal at the start of operation of the power conversion device (hereinafter referred to as an operation start signal) Start trigger, and the limit compensation amount until the time constant ⁇ elapses after the operation start signal Start trigger is input.
  • 0 is output as V_cmp_o
  • the neutral point potential compensation amount V_cmp is output as the limit compensation amount V_cmp_o after the time constant ⁇ elapses after the operation start signal Start trigger is input.
  • the time constant ⁇ is calculated based on the d-axis inductance Ld, the q-axis inductance Lq, and the resistance R of the connected motor M.
  • the values of the d-axis inductance Ld, the q-axis inductance Lq, and the resistance R are determined in advance by an impedance measurement test of the motor M or the like.
  • V_cmd ′ V_cmd.
  • V_cmd ′ V_cmd.
  • V_cmp V_cmd + V_cmp.
  • the correction voltage command value V_cmd ′ is neutral during the period from the start of operation of the power conversion device (that is, at the time of motor start) to the time constant ⁇ . It operates only with the three-phase voltage command value V_cmd calculated by the current control without being affected by the potential compensation amount V_cmd. Therefore, current control and neutral point potential control do not interfere, and the output voltage of the power converter operates stably. As a result, a failure stop due to overcurrent protection or overvoltage protection does not occur. Further, since the gains of the current control and neutral point potential control are not lowered in the steady state, it is possible to suppress the deterioration of the control performance in the steady state.
  • the limit compensation amount V_cmp_o is made variable according to the passage of time using the operation start signal Start trigger as a trigger. Others are the same as in the first embodiment.
  • variable limiter 5 is provided instead of the delay counter 4, and an operation start signal Start trigger of the power conversion device and a neutral point potential compensation amount V_cmp are input.
  • variable limiter 5 does not add the compensation amount step by step, but outputs 0 as the limit compensation amount V_cmp_o until the operation start signal Start trigger is input, and the operation start signal Start trigger is input as shown in FIG.
  • the limit compensation amount V_cmp_o is gradually increased in a cushioned manner until the time constant ⁇ , and the neutral point potential compensation amount is set as the limit compensation amount V_cmp_o after the time constant ⁇ elapses after the operation start signal Start trigger is input.
  • V_cmp is output as it is.
  • the limit compensation amount V_cmp_o can be reduced during the period from the start of operation of the power conversion device (that is, when the motor is started) to the time constant ⁇ , interference between current control and neutral point potential control can occur. It becomes small and it becomes possible to stabilize the output voltage of a power converter device. Further, since the neutral point potential compensation amount V_cmp is output as it is as the limit compensation amount V_cmp_0 and the gain is not lowered at the steady state, it is possible to suppress the deterioration of the control performance at the steady state.
  • FIG. 4 shows a main circuit configuration diagram of a three-phase neutral point clamp type power conversion device interconnected with the grid. Input filters Lf and Cf are inserted between the three-phase system voltages Vrs, Vst and Vtr and the three-phase neutral point clamp type power converter.
  • FIG. 5 shows a block diagram of the DC voltage control and current control block of FIG. 4 and 5, the system voltages Vrs, Vst, and Vtr are measured, and the system phase pll_out is obtained using a PLL (Phase Locked Loop) circuit.
  • PLL Phase Locked Loop
  • the three-phase two-phase converter 1 converts the three-phase current detection values (system currents) Ir, Is, It into the d-axis current detection value Id_det and the q-axis current detection value Iq_det based on the system phase pll_out. Is converted to Further, the two-phase three-phase converter 2 converts the two-phase voltage command values Vd_cmd and Vq_cmd into the three-phase voltage command value V_cmd based on the system phase pll_out.
  • Vdc_cmd command for the voltage between PN terminals in FIG. 4
  • AVR voltage control: Automatic Voltage Regulator
  • the correction voltage command value V_cmd ′ reaches the threshold value by adding the compensation amounts of the current control and neutral point potential control during the boosting operation at the start of operation of the power converter, and the limit processing voltage command value V_cmd ′. Since 'is easily restricted, a delay counter 4 is provided. The delay counter 4 calculates a time constant ⁇ based on the input filter inductance Lf and the capacitor Cf. The limit compensation amount V_vmp_o is set to 0 until the time constant ⁇ elapses after the operation start signal Start trigger is input. After the time constant ⁇ has elapsed after the operation start signal Start trigger is input, the limit compensation amount V_cmp_o is medium. By outputting the neutral point potential compensation amount V_cmp as it is, current control and neutral point potential control are made non-interfering, and stable control characteristics can be obtained. As a result, the system currents Ir, Is, It are stabilized.
  • the control circuit of the third embodiment is provided with a variable limiter 5 instead of the delay counter 4 as in the second embodiment.
  • FIG. 6 shows a control circuit according to the fourth embodiment.
  • variable limiter 5 may be performed in the same manner as in the second embodiment.
  • the limit compensation amount V_cmp_o can be reduced at the start of operation of the power converter, and the neutral point potential compensation amount V_cmp can be used as the limit compensation amount V_cmp_o in the steady state. Can be output as they are, so that the interference between the current control and the neutral point potential control is reduced without degrading the control performance in the steady state, and stable control characteristics can be obtained. As a result, the alternating currents Ir, Is, It are stabilized.

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Abstract

In the present invention, in a current control unit AVR, PI control is carried out and voltage command values Vd_cmd, Vq_cmd are calculated, on the basis of the deviation between a d-axis current command value Id_cmd and a d-axis current detection value Id_det and the deviation between a q-axis current command value Iq_cmd and a q-axis current detection value Iq_det. In addition, a neutral point potential control unit NPC calculates a neutral point potential compensation amount V_cmp for compensating the voltage deviation of smoothing capacitors which are connected in series. In a limiting means 4, the neutral point potential compensation amount V_cmp is limited from when operation begins until a preset amount of time has elapsed. In an adder 3, the limited neutral point potential compensation amount V_cmp and the voltage command value Vd_cmd are added, and a compensation voltage command value V_cmd' is calculated. On the basis of the compensation voltage command value V_cmd', PWM control is carried out by a PWM control unit PWM. Due to this configuration, in a three-phase neutral point clamped power conversion device in which PWM control is carried out, interference between current control and neutral point potential control is suppressed.

Description

三相中性点クランプ式の電力変換装置Three-phase neutral point clamp type power converter
　本発明は、三相中性点クランプ式のマルチレベル電力変換装置に係り、特に、ＰＷＭ制御を用いた中性点電圧制御に関する。 The present invention relates to a three-phase neutral point clamp type multi-level power converter, and more particularly to neutral point voltage control using PWM control.
　図７は、モータ負荷を接続した三相中性点クランプ式の電力変換装置における主回路を示す構成図である。スイッチングデバイス（図７ではＩＧＢＴ）Ｓ１～Ｓ１２にゲート指令を入力することによりスイッチングデバイスＳ１～Ｓ１２をＯＮ／ＯＦＦ動作させ、出力端子Ｕ，Ｖ，Ｗに交流電圧を出力する。 FIG. 7 is a configuration diagram showing a main circuit in a three-phase neutral point clamp type power converter connected to a motor load. By inputting a gate command to the switching devices (IGBT in FIG. 7) S1 to S12, the switching devices S1 to S12 are turned ON / OFF, and an AC voltage is output to the output terminals U, V, and W.
　この電力変換装置は直流電圧Ｐ－Ｎ間を平滑コンデンサＣｄｃ１，Ｃｄｃ２により分割し、直流電位Ｐ、Ｎおよび中性点電位ＮＰの３レベルの電位をＰＷＭ変調（Ｐｕｌｓｅ　Ｗｉｄｔｈ　Ｍｏｄｕｌａｔｉｏｎ）を用いて出力するものである。 This power converter divides the DC voltage PN between the smoothing capacitors Cdc1 and Cdc2, and outputs three-level potentials of the DC potentials P and N and the neutral point potential NP using PWM modulation (Pulse Width Modulation). Is.
　ＡＣＲ（電流制御：Ａｕｔｏｍａｔｉｃ　Ｃｕｒｒｅｎｔ　Ｒｅｇｕｌａｔｏｒ）の後、直流電圧Ｖｄｃ１とＶｄｃ２のばらつきを抑える中性点電位制御（Ｎｅｕｔｒａｌ　Ｐｏｉｎｔ　Ｃｏｎｔｒｏｌ）を行っている。中性点電位制御は直流電圧Ｐ－Ｎ間の正極側（Ｐ側）の平滑コンデンサＣｄｃ１の直流電圧Ｖｄｃ１と、負極側（Ｎ側）の平滑コンデンサＣｄｃ２の直流電圧Ｖｄｃ２の偏差をとり、この偏差が零になるように制御を行うものである。 After neutral current regulator (ACR), neutral point potential control (Neutral Point Control) is performed to suppress variations in DC voltages Vdc1 and Vdc2. The neutral point potential control takes a deviation between the DC voltage Vdc1 of the smoothing capacitor Cdc1 on the positive electrode side (P side) between the DC voltages PN and the DC voltage Vdc2 of the smoothing capacitor Cdc2 on the negative electrode side (N side). Is controlled so that becomes zero.
　この電力変換装置の三相交流出力に接続する負荷をモータＭとして電流制御をする場合を例にとり、電力変換装置の制御回路を説明する。図８は、三相中性点クランプ式の電力変換装置の制御回路を示すブロック図である。 The control circuit of the power conversion device will be described by taking as an example a case where current control is performed using the load connected to the three-phase AC output of the power conversion device as the motor M. FIG. 8 is a block diagram showing a control circuit of a three-phase neutral point clamp type power converter.
　モータＭには位相検出器ｅｎｃが取り付けられており、位相検出値をｔｈｅｔａ＿ｄｅｔとする。三相二相変換器１において、三相電流（モータ電流）Ｉｕ，Ｉｖ，Ｉｗを位相検出値ｔｈｅｔａ＿ｄｅｔに基づいて三相二相変換し、ｄ軸電流検出値Ｉｄ＿ｄｅｔおよびｑ軸電流検出値Ｉｑ＿ｄｅｔを得る。 The phase detector enc is attached to the motor M, and the phase detection value is theta_det. In the three-phase to two-phase converter 1, three-phase currents (motor currents) Iu, Iv, and Iw are three-phase to two-phase converted based on the phase detection value theta_det, and a d-axis current detection value Id_det and a q-axis current detection value Iq_det are obtained. obtain.
　次に、電流制御部ＡＣＲにおいて、ｄ軸電流指令値Ｉｄ＿ｃｍｄ，ｑ軸電流指令値Ｉｑ＿ｃｍｄを目標値とし、この目標値にｄ軸電流検出値Ｉｄ＿ｄｅｔ，Ｉｑ＿ｄｅｔが追従するようにＰＩ制御を行う。電流制御部ＡＣＲの出力は二相電圧指令値Ｖｄ＿ｃｍｄ，Ｖｑ＿ｃｍｄとなる。 Next, in the current control unit ACR, the d-axis current command value Id_cmd and the q-axis current command value Iq_cmd are set as target values, and PI control is performed so that the d-axis current detection values Id_det and Iq_det follow the target values. The output of the current control unit ACR becomes the two-phase voltage command values Vd_cmd and Vq_cmd.
　二相電圧指令値Ｖｄ＿ｃｍｄ，Ｖｑ＿ｃｍｄは、二相三相変換器２により二相三相変換が行われ、三相電圧指令値Ｖ＿ｃｍｄが生成される。次に、中性点電位制御部ＮＰＣにおいて、直流電圧Ｖｄｃ１，Ｖｄｃ２に基づいて中性点電位補償量Ｖ＿ｃｍｐを演算する。加算器３において、三相電圧指令値Ｖ＿ｃｍｄに中性点電位補償量Ｖ＿ｃｍｐを加算し、加算後の電圧指令を補正電圧指令値Ｖ＿ｃｍｄ'とする。 The two-phase voltage command values Vd_cmd and Vq_cmd are subjected to two-phase / three-phase conversion by the two-phase / three-phase converter 2 to generate a three-phase voltage command value V_cmd. Next, the neutral point potential control unit NPC calculates a neutral point potential compensation amount V_cmp based on the DC voltages Vdc1 and Vdc2. In the adder 3, the neutral point potential compensation amount V_cmp is added to the three-phase voltage command value V_cmd, and the voltage command after the addition is set as a correction voltage command value V_cmd ′.
　さらに、この補正電圧指令値Ｖ＿ｃｍｄ’に対し、リミッタＬＭＴにより電圧制限をかけ、リミット処理電圧指令値Ｖ＿ｃｍｄ’’をＰＷＭ処理部ＰＷＭへ入力する。ここで、リミッタＬＭＴは補正電圧指令値Ｖ＿ｃｍｄ’が閾値を下回る場合、補正電圧指令値をそのままリミット処理電圧指令値Ｖ＿ｃｍｄ’’として出力し、補正電圧指令値Ｖ＿ｃｍｄ’が閾値以上の場合、閾値をリミット処理電圧指令値Ｖ＿ｃｍｄ’’として出力する。リミッタＬＭＴを設ける目的は、後述のゲート指令ＧＩ＿Ｈ，ＧＩ＿Ｌが異常なパルス（極小パルスなど）となることを抑制し、電力変換装置の出力電圧や出力電流に歪が生じることを防止するためである。 Further, the correction voltage command value V_cmd ′ is limited by the limiter LMT, and the limit processing voltage command value V_cmd ″ is input to the PWM processing unit PWM. Here, the limiter LMT outputs the correction voltage command value as it is as the limit processing voltage command value V_cmd ″ when the correction voltage command value V_cmd ′ is below the threshold value, and sets the threshold value when the correction voltage command value V_cmd ′ is equal to or greater than the threshold value. Output as limit processing voltage command value V_cmd ″. The purpose of providing the limiter LMT is to prevent the gate commands GI_H and GI_L, which will be described later, from becoming abnormal pulses (minimum pulses, etc.) and to prevent distortion in the output voltage and output current of the power converter. .
　ＰＷＭ処理部ＰＷＭでは、リミット処理電圧指令値Ｖｃｍｄ’’を用いて、各スイッチングデバイスＳ１～Ｓ１２のゲート指令ＧＩ＿Ｈ，ＧＩ＿Ｌを生成する。図８には示していないが、三角波キャリア信号とリミット処理電圧指令値Ｖ＿ｃｍｄ’’を比較してゲート指令ＧＩ＿Ｈ，ＧＩ＿Ｌを生成する方法が一般的である。 The PWM processing unit PWM generates the gate commands GI_H and GI_L of the switching devices S1 to S12 using the limit processing voltage command value Vcmd ″. Although not shown in FIG. 8, a method of generating the gate commands GI_H and GI_L by comparing the triangular wave carrier signal and the limit processing voltage command value V_cmd ″ is general.
　上記の技術は、特許文献１～３に記載されている。 The above techniques are described in Patent Documents 1 to 3.
　図８に示すように、補正電圧指令値Ｖ＿ｃｍｐ’は、三相電圧指令値Ｖ＿ｃｍｄに中性点電位補償量Ｖ＿ｃｍｐを加算した値である。電力変換装置の運転開始時すなわちモータＭの始動時は、モータＭの始動トルクの関係で大きな電力変換装置の出力電流（すなわちモータ電流）が必要になるため、電流制御部ＡＣＲの出力を二相三相変換した三相電圧指令値Ｖ＿ｃｍｄも大きくなる。 As shown in FIG. 8, the corrected voltage command value V_cmp ′ is a value obtained by adding the neutral point potential compensation amount V_cmp to the three-phase voltage command value V_cmd. At the start of operation of the power converter, that is, when the motor M starts, a large output current of the power converter (that is, motor current) is required due to the starting torque of the motor M, so the output of the current control unit ACR is two-phase. The three-phase voltage command value V_cmd after the three-phase conversion also increases.
　この三相電圧指令値Ｖ＿ｃｍｄと中性点電位補償量Ｖ＿ｃｍｐが重畳すると、補正電圧指令値Ｖ＿ｃｍｄ’が閾値に達しやすくリミッタＬＭＴの動作によりリミット処理電圧指令値に制限がかかり、Ｖ＿ｃｍｄ’≠Ｖ＿ｃｍｄ’’となる。その結果、安定動作が困難となり、電力変換装置の出力電流や出力電圧が過電流・過電圧になることがある。その場合、過電流保護や過電圧保護などで故障停止してしまい、電力変換装置を運転できなくなる。 When the three-phase voltage command value V_cmd and the neutral point potential compensation amount V_cmd are superimposed, the correction voltage command value V_cmd ′ easily reaches the threshold value, and the limit processing voltage command value is limited by the operation of the limiter LMT, and V_cmd ′ ≠ V_cmd ′. 'Become. As a result, stable operation becomes difficult, and the output current and output voltage of the power converter may become overcurrent / overvoltage. In such a case, the power conversion device cannot be operated due to failure stop due to overcurrent protection or overvoltage protection.
　また、図７の平滑コンデンサＣｄｃ１，Ｃｄｃ２のコンデンサ容量は等しくすることが一般的であるが、製造のばらつきや経年劣化などにより初期充電値の偏差すなわち直流電圧Ｖｄｃ１とＶｄｃ２の偏差が大きくなる。すなわち、起動直後の中性点電位補償量Ｖ＿ｃｍｐは大きくなりやすい。これらの要因から補正電圧指令値Ｖ＿ｃｍｄ’が閾値に達してリミット処理電圧指令値Ｖ＿ｃｍｄ’’が制限されることを回避するには電流制御もしくは中性点電圧制御のゲインを下げることになる。しかし、そのトレードオフとして、定常時の制御性能が低下する。そこで中性点電位制御のゲインを下げることなく電流制御と中性点電位制御の干渉を考慮した制御機構が必要になる。 In addition, although the capacitor capacities of the smoothing capacitors Cdc1 and Cdc2 in FIG. 7 are generally equal, the deviation of the initial charge value, that is, the deviation between the DC voltages Vdc1 and Vdc2 becomes large due to manufacturing variations and aging degradation. That is, the neutral point potential compensation amount V_cmp immediately after startup tends to increase. In order to avoid the correction voltage command value V_cmd 'reaching the threshold value and limiting the limit processing voltage command value V_cmd "from these factors, the gain of the current control or neutral point voltage control is lowered. However, as a trade-off, the steady-state control performance decreases. Therefore, a control mechanism that takes into account the interference between current control and neutral point potential control without reducing the gain of neutral point potential control is required.
　以上示したように、ＰＷＭ制御を行う三相中性点クランプ式の電力変換装置において、電流制御と中性点電位制御の干渉を抑制することが課題となる。 As described above, in the three-phase neutral point clamp type power converter that performs PWM control, it becomes a problem to suppress interference between current control and neutral point potential control.
ＷＯ９７／２５７６６WO97 / 25766 特開平６－２３３５３７号公報JP-A-6-233537 特開平１０－２４８２６２号公報Japanese Patent Laid-Open No. 10-248262
　本発明は、前記従来の問題に鑑み、案出されたもので、その一態様は、 三相中性点クランプ式の電力変換装置であって、その制御回路は、ｄ軸電流指令値とｄ軸電流検出値との偏差、および、ｑ軸電流指令値とｑ軸電流検出値との偏差に基づいてＰＩ制御を行う電流制御機能により、二相電圧指令値を演算する電流制御部と、二相電圧指令値を三相電圧指令値に変換する二相三相変換部と、直列接続された平滑コンデンサの電圧偏差を補償する中性点電位補償量を演算する中性点電位制御部と、電力変換装置の運転開始時から予め設定された時間経過するまで制限補償量として中性点電位補償量を制限した値を出力し、電力変換装置の運転開始時から予め設定された時間経過後は制限補償量として中性点電位補償量をそのまま出力する制限手段と、制限補償量と三相電圧指令値を加算し、補正電圧指令値を演算する加算部と、補正電圧指令値が閾値を下回る場合、補正電圧指令値をそのままリミット処理電圧指令値として出力し、補正電圧指令値が閾値以上の場合、閾値をリミット処理電圧指令値として出力するリミッタと、前記リミット処置電圧指令値に基づいてＰＷＭ制御をするＰＷＭ制御部と、を備えたことを特徴とする。 The present invention has been devised in view of the above-described conventional problems. One aspect of the present invention is a three-phase neutral point clamp type power converter, and its control circuit includes a d-axis current command value and d A current control unit that calculates a two-phase voltage command value by a current control function that performs PI control based on a deviation from the detected shaft current value and a deviation between the q-axis current command value and the q-axis current detected value; A two-phase three-phase conversion unit that converts a phase voltage command value into a three-phase voltage command value, a neutral point potential control unit that calculates a neutral point potential compensation amount that compensates for a voltage deviation of a smoothing capacitor connected in series, Output a value that limits the neutral point potential compensation amount as a limit compensation amount until a preset time has elapsed since the start of operation of the power converter, and after a preset time has elapsed since the start of the operation of the power converter The neutral point potential compensation amount is output as it is as the limit compensation amount. Means, adding the limit compensation amount and three-phase voltage command value, and calculating the correction voltage command value, and when the correction voltage command value is below the threshold value, the correction voltage command value is output as the limit processing voltage command value. And a limiter that outputs the threshold value as a limit processing voltage command value when the correction voltage command value is equal to or greater than the threshold value, and a PWM control unit that performs PWM control based on the limit treatment voltage command value. To do.
　また、その一態様として、前記制限手段は、電力変換装置が運転を開始してから予め設定された時間経過するまで制限補償量を０とすることを特徴とする。 Further, as one aspect thereof, the limiting means sets the limit compensation amount to 0 until a preset time elapses after the power converter starts operation.
　また、他の態様として、前記制限手段は、電力変換装置が運転開始するまで制限補償量を０とし、電力変換装置が運転開始してから予め設定された時間経過するまでの間に制限補償量を徐々に増加させることを特徴とする。 As another aspect, the limiting means sets the limit compensation amount to 0 until the power conversion device starts operation, and the limit compensation amount until a preset time elapses after the power conversion device starts operation. Is gradually increased.
　また、その一態様として、前記電力変換装置の三相交流出力に接続する負荷はモータであり、モータの位相検出値に基づいて三相電流検出値をｄ軸電流検出値，ｑ軸電流検出値に変換し、モータの位相検出値に基づいて二相電圧指令値を三相電圧指令値に変換することを特徴とする。 Further, as one aspect thereof, the load connected to the three-phase AC output of the power converter is a motor, and the three-phase current detection value is converted to the d-axis current detection value and the q-axis current detection value based on the phase detection value of the motor The two-phase voltage command value is converted into a three-phase voltage command value based on the phase detection value of the motor.
　また、他の態様として、前記電力変換装置は系統に連系されており、系統位相の検出値に基づいて三相電流検出値をｄ軸電流検出値，ｑ軸電流検出値に変換し、系統位相の検出値に基づいて二相電圧指令値を三相電圧指令値に変換することを特徴とする。 As another aspect, the power conversion device is connected to a grid, and converts a three-phase current detection value into a d-axis current detection value and a q-axis current detection value based on a detection value of the system phase. The two-phase voltage command value is converted into a three-phase voltage command value based on the phase detection value.
　本発明によれば、ＰＷＭ制御を行う三相中性点クランプ式の電力変換装置において、電流制御と中性点電位制御の干渉を抑制することが可能となる。 According to the present invention, in a three-phase neutral point clamp type power converter that performs PWM control, it is possible to suppress interference between current control and neutral point potential control.
実施形態１における制御回路を示すブロック図。FIG. 2 is a block diagram illustrating a control circuit according to the first embodiment. 実施形態２における制御回路を示すブロック図。FIG. 4 is a block diagram illustrating a control circuit in a second embodiment. 実施形態２における可変リミッタの入出力動作を示すタイムチャート。9 is a time chart showing an input / output operation of a variable limiter according to the second embodiment. 系統に連系した三相中性点クランプ式の電力変換装置の主回路構成図。The main circuit block diagram of the three-phase neutral point clamp type power converter connected to the system. 実施形態３における制御回路を示すブロック図。FIG. 9 is a block diagram illustrating a control circuit according to a third embodiment. 実施形態４における制御回路を示すブロック図。FIG. 9 is a block diagram illustrating a control circuit according to a fourth embodiment. モータ負荷に接続した三相中性点クランプ式の電力変換装置の主回路構成図。The main circuit block diagram of the three-phase neutral point clamp type power converter connected to the motor load. 従来における制御回路の一例を示すブロック図。The block diagram which shows an example of the conventional control circuit.
　以下、本発明に係る三相中性点クランプ式のマルチレベル電力変換装置における実施形態１～４を図１～図６に基づいて詳述する。 Embodiments 1 to 4 of the three-phase neutral point clamp type multilevel power conversion device according to the present invention will be described below in detail with reference to FIGS.
　［実施形態１］
　図１は、本実施形態１における電力変換装置の制御回路を示すブロック図である。本実施形態１の制御回路は、電流制御と中性点電位制御の干渉を考慮している。図８と同一の箇所は同一符号を付してその説明を省略する。 [Embodiment 1]
FIG. 1 is a block diagram illustrating a control circuit of the power conversion device according to the first embodiment. The control circuit of the first embodiment takes into account interference between current control and neutral point potential control. The same parts as those in FIG.
　本実施形態１では、図１に示すように中性点電位制御部ＮＰＣが出力する中性点電位補償量Ｖ＿ｃｍｐを電力変換装置の運転開始時から予め設定された時間経過するまで制限手段（本実施形態１ではディレイカウンタ４）により制限する。ディレイカウンタ４は、電力変換装置の運転開始時の信号（以下、運転開始信号と称する）Ｓｔａｒｔ　ｔｒｉｇｇｅｒをトリガとし、運転開始信号Ｓｔａｒｔ　ｔｒｉｇｇｅｒが入力されてから時定数τが経過するまでは制限補償量Ｖ＿ｃｍｐ＿ｏとして０を出力し、運転開始信号Ｓｔａｒｔ　ｔｒｉｇｇｅｒが入力されてから時定数τが経過後は制限補償量Ｖ＿ｃｍｐ＿ｏとして中性点電位補償量Ｖ＿ｃｍｐを出力する。 In the first embodiment, as shown in FIG. 1, the neutral point potential compensation amount V_cmp output by the neutral point potential control unit NPC is limited until the preset time elapses from the start of operation of the power converter. In the first embodiment, the delay is limited by the delay counter 4). The delay counter 4 is triggered by a signal at the start of operation of the power conversion device (hereinafter referred to as an operation start signal) Start trigger, and the limit compensation amount until the time constant τ elapses after the operation start signal Start trigger is input. 0 is output as V_cmp_o, and the neutral point potential compensation amount V_cmp is output as the limit compensation amount V_cmp_o after the time constant τ elapses after the operation start signal Start trigger is input.
　ディレイカウンタ４では接続されたモータＭのｄ軸インダクタンスＬｄとｑ軸インダクタンスＬｑと抵抗Ｒとに基づき、時定数τが算出されている。ここでｄ軸インダクタンスＬｄ，ｑ軸インダクタンスＬｑ，抵抗Ｒの値は、別途モータＭのインピーダンス測定試験などによってあらかじめ求めておくこととする。 In the delay counter 4, the time constant τ is calculated based on the d-axis inductance Ld, the q-axis inductance Lq, and the resistance R of the connected motor M. Here, the values of the d-axis inductance Ld, the q-axis inductance Lq, and the resistance R are determined in advance by an impedance measurement test of the motor M or the like.
　電力変換装置の運転開始から時定数τまでの期間では、ディレイカウンタ４は零を出力するため、Ｖ＿ｃｍｄ’＝Ｖ＿ｃｍｄとなる。一方、運転開始時から時定数τの時間経過後に、制限補償量Ｖ＿ｃｍｐ＿ｏとして中性点電位補償量Ｖ＿ｃｍｐを三相電圧指令値Ｖ＿ｃｍｄに加算する。したがって、Ｖ＿ｃｍｄ’＝Ｖ＿ｃｍｄ＋Ｖ＿ｃｍｐとなる。 In the period from the start of operation of the power conversion device to the time constant τ, the delay counter 4 outputs zero, so V_cmd ′ = V_cmd. On the other hand, the neutral point potential compensation amount V_cmp is added to the three-phase voltage command value V_cmd as the limit compensation amount V_cmp_o after the time constant τ elapses from the start of operation. Therefore, V_cmd '= V_cmd + V_cmp.
　以上示したように、本実施形態１における電力変換装置によれば、電力変換装置の運転開始時（すなわちモータ始動時）から上記時定数τまでの期間、補正電圧指令値Ｖ＿ｃｍｄ’は中性点電位補償量Ｖ＿ｃｍｐから影響せずに電流制御で算出された三相電圧指令値Ｖ＿ｃｍｄのみで動作する。そのため、電流制御と中性点電位制御は干渉せず、電力変換装置の出力電圧は安定して動作する。その結果、過電流保護や過電圧保護による故障停止が発生しない。また、定常時において電流制御と中性点電位制御のゲインを下げていないため定常時の制御性能が低下することを抑制することが可能となる。 As described above, according to the power conversion device of the first embodiment, the correction voltage command value V_cmd ′ is neutral during the period from the start of operation of the power conversion device (that is, at the time of motor start) to the time constant τ. It operates only with the three-phase voltage command value V_cmd calculated by the current control without being affected by the potential compensation amount V_cmd. Therefore, current control and neutral point potential control do not interfere, and the output voltage of the power converter operates stably. As a result, a failure stop due to overcurrent protection or overvoltage protection does not occur. Further, since the gains of the current control and neutral point potential control are not lowered in the steady state, it is possible to suppress the deterioration of the control performance in the steady state.
　［実施形態２］
　本実施形態２は、制限補償量Ｖ＿ｃｍｐ＿ｏを運転開始信号Ｓｔａｒｔ　ｔｒｉｇｇｅｒをトリガとして時間経過に応じて可変にしたものである。その他は実施形態１と同様である。 [Embodiment 2]
In the second embodiment, the limit compensation amount V_cmp_o is made variable according to the passage of time using the operation start signal Start trigger as a trigger. Others are the same as in the first embodiment.
　具体的には、ディレイカウンタ４の代わりに可変リミッタ５を設け、電力変換装置の運転開始信号Ｓｔａｒｔ　ｔｒｉｇｇｅｒと、中性点電位補償量Ｖ＿ｃｍｐと、を入力する。 Specifically, a variable limiter 5 is provided instead of the delay counter 4, and an operation start signal Start trigger of the power conversion device and a neutral point potential compensation amount V_cmp are input.
　可変リミッタ５は、ステップ的に補償量を加算するのではなく、図３に示すように、運転開始信号Ｓｔａｒｔ　ｔｒｉｇｇｅｒ入力するまで制限補償量Ｖ＿ｃｍｐ＿ｏとして０を出力し、運転開始信号Ｓｔａｒｔ　ｔｒｉｇｇｅｒが入力されてから時定数τまでの時間をクッション的に、制限補償量Ｖ＿ｃｍｐ＿ｏを徐々に増加させ、運転開始信号Ｓｔａｒｔ　ｔｒｉｇｇｅｒが入力されてから時定数τ経過後、制限補償量Ｖ＿ｃｍｐ＿ｏとして中性点電位補償量Ｖ＿ｃｍｐをそのまま出力する。 The variable limiter 5 does not add the compensation amount step by step, but outputs 0 as the limit compensation amount V_cmp_o until the operation start signal Start trigger is input, and the operation start signal Start trigger is input as shown in FIG. The limit compensation amount V_cmp_o is gradually increased in a cushioned manner until the time constant τ, and the neutral point potential compensation amount is set as the limit compensation amount V_cmp_o after the time constant τ elapses after the operation start signal Start trigger is input. V_cmp is output as it is.
　本実施形態２によれば、電力変換装置の運転開始時（すなわちモータ始動時）から上記時定数τまでの期間、制限補償量Ｖ＿ｃｍｐ＿ｏを小さくできるため、電流制御と中性点電位制御の干渉が小さくなり、電力変換装置の出力電圧を安定させることが可能となる。また、定常時は制限補償量Ｖ＿ｃｍｐ＿０として中性点電位補償量Ｖ＿ｃｍｐをそのまま出力しゲインを下げていないため、定常時の制御性能が低下することを抑制することが可能となる。 According to the second embodiment, since the limit compensation amount V_cmp_o can be reduced during the period from the start of operation of the power conversion device (that is, when the motor is started) to the time constant τ, interference between current control and neutral point potential control can occur. It becomes small and it becomes possible to stabilize the output voltage of a power converter device. Further, since the neutral point potential compensation amount V_cmp is output as it is as the limit compensation amount V_cmp_0 and the gain is not lowered at the steady state, it is possible to suppress the deterioration of the control performance at the steady state.
　［実施形態３］
　本実施形態３では、系統連系を行い直流電圧Ｖｄｃ１，Ｖｄｃ２の制御を行う場合を考える。まず、図４に系統連系した三相中性点クランプ式の電力変換装置の主回路構成図を示す。三相の系統電圧Ｖｒｓ，Ｖｓｔ，Ｖｔｒと三相中性点クランプ式の電力変換装置との間に、入力フィルタＬｆ，Ｃｆを挿入している。 [Embodiment 3]
In the third embodiment, a case is considered in which grid connection is performed to control the DC voltages Vdc1 and Vdc2. First, FIG. 4 shows a main circuit configuration diagram of a three-phase neutral point clamp type power conversion device interconnected with the grid. Input filters Lf and Cf are inserted between the three-phase system voltages Vrs, Vst and Vtr and the three-phase neutral point clamp type power converter.
　続いて、図５に図４の直流電圧制御，電流制御ブロック構成図を示す。図４，５の基準電圧をＶｒｓとし、系統電圧Ｖｒｓ，Ｖｓｔ，Ｖｔｒを計測しＰＬＬ（Ｐｈａｓｅ　Ｌｏｃｋｅｄ　Ｌｏｏｐ）回路を用いて系統位相ｐｌｌ＿ｏｕｔを求める。 Subsequently, FIG. 5 shows a block diagram of the DC voltage control and current control block of FIG. 4 and 5, the system voltages Vrs, Vst, and Vtr are measured, and the system phase pll_out is obtained using a PLL (Phase Locked Loop) circuit.
　本実施形態３では、三相二相変換器１により、系統位相ｐｌｌ＿ｏｕｔに基づいて、三相電流検出値（系統電流）Ｉｒ，Ｉｓ，Ｉｔがｄ軸電流検出値Ｉｄ＿ｄｅｔ，ｑ軸電流検出値Ｉｑ＿ｄｅｔに変換される。また、二相三相変換器２により、系統位相ｐｌｌ＿ｏｕｔに基づいて、二相電圧指令値Ｖｄ＿ｃｍｄ，Ｖｑ＿ｃｍｄが三相電圧指令値Ｖ＿ｃｍｄに変換される。 In the third embodiment, the three-phase two-phase converter 1 converts the three-phase current detection values (system currents) Ir, Is, It into the d-axis current detection value Id_det and the q-axis current detection value Iq_det based on the system phase pll_out. Is converted to Further, the two-phase three-phase converter 2 converts the two-phase voltage command values Vd_cmd and Vq_cmd into the three-phase voltage command value V_cmd based on the system phase pll_out.
　また、本実施形態３では、直流電圧指令Ｖｄｃ＿ｃｍｄ（図４のＰＮ端子間電圧の指令）と直流電圧Ｖｄｃ１，Ｖｄｃ２の和との偏差をとり、ＡＶＲ（電圧制御：Ａｕｔｏｍａｔｉｃ　Ｖｏｌｔａｇｅ　Ｒｅｇｕｌａｔｏｒ）をかけた値を電流制御のｄ軸電流指令値Ｉｄ＿ｃｍｄ，ｑ軸電流指令値Ｉｑ＿ｃｍｄとしている。なお、ＡＶＲの構成については、特許文献２に示されている。その他は実施形態１と同様である。 In the third embodiment, a value obtained by taking a deviation between the DC voltage command Vdc_cmd (command for the voltage between PN terminals in FIG. 4) and the sum of the DC voltages Vdc1 and Vdc2 and applying AVR (voltage control: Automatic Voltage Regulator). Are d-axis current command value Id_cmd and q-axis current command value Iq_cmd for current control. The configuration of AVR is shown in Patent Document 2. Others are the same as in the first embodiment.
　系統連系時は、電力変換装置の運転開始時における昇圧動作時に電流制御と中性点電位制御の補償量を加算することで補正電圧指令値Ｖ＿ｃｍｄ’が閾値に達しリミット処理電圧指令値Ｖ＿ｃｍｄ’’が制限されやすいため、ディレイカウンタ４を設ける。ディレイカウンタ４では、入力フィルタのインダクタンスＬｆとコンデンサＣｆに基づき、時定数τを算出する。運転開始信号Ｓｔａｒｔ　ｔｒｉｇｇｅｒが入力されてから時定数τの時間経過までは制限補償量Ｖ＿ｖｍｐ＿ｏを０とし、運転開始信号Ｓｔａｒｔ　ｔｒｉｇｇｅｒが入力されてから時定数τの時間経過後に、制限補償量Ｖ＿ｃｍｐ＿ｏとして中性点電位補償量Ｖ＿ｃｍｐをそのまま出力することで、電流制御と中性点電位制御が非干渉化し、安定した制御特性を得ることができる。これにより、系統電流Ｉｒ，Ｉｓ，Ｉｔが安定化する。 At the time of grid connection, the correction voltage command value V_cmd ′ reaches the threshold value by adding the compensation amounts of the current control and neutral point potential control during the boosting operation at the start of operation of the power converter, and the limit processing voltage command value V_cmd ′. Since 'is easily restricted, a delay counter 4 is provided. The delay counter 4 calculates a time constant τ based on the input filter inductance Lf and the capacitor Cf. The limit compensation amount V_vmp_o is set to 0 until the time constant τ elapses after the operation start signal Start trigger is input. After the time constant τ has elapsed after the operation start signal Start trigger is input, the limit compensation amount V_cmp_o is medium. By outputting the neutral point potential compensation amount V_cmp as it is, current control and neutral point potential control are made non-interfering, and stable control characteristics can be obtained. As a result, the system currents Ir, Is, It are stabilized.
　［実施形態４］
　本実施形態４は、実施形態３の制御回路に対し、実施形態２と同様に、ディレイカウンタ４の代わりに可変リミッタ５を設けたものである。図６に本実施形態４における制御回路を示す。 [Embodiment 4]
In the fourth embodiment, the control circuit of the third embodiment is provided with a variable limiter 5 instead of the delay counter 4 as in the second embodiment. FIG. 6 shows a control circuit according to the fourth embodiment.
　可変リミッタ５の動作は、実施形態２と同様の演算をすればよく、電力変換装置の運転開始時は制限補償量Ｖ＿ｃｍｐ＿ｏを小さくでき、定常時は制限補償量Ｖ＿ｃｍｐ＿ｏとして中性点電位補償量Ｖ＿ｃｍｐをそのまま出力できるため、定常時の制御性能を低下することなく、電流制御と中性点電位制御の干渉が小さくなり、安定した制御特性を得ることができる。これにより、交流電流Ｉｒ，Ｉｓ，Ｉｔが安定化する。 The operation of the variable limiter 5 may be performed in the same manner as in the second embodiment. The limit compensation amount V_cmp_o can be reduced at the start of operation of the power converter, and the neutral point potential compensation amount V_cmp can be used as the limit compensation amount V_cmp_o in the steady state. Can be output as they are, so that the interference between the current control and the neutral point potential control is reduced without degrading the control performance in the steady state, and stable control characteristics can be obtained. As a result, the alternating currents Ir, Is, It are stabilized.
　以上、本発明において、記載された具体例に対してのみ詳細に説明したが、本発明の技術思想の範囲で多彩な変形および修正が可能であることは、当業者にとって明白なことであり、このような変形および修正が特許請求の範囲に属することは当然のことである。 Although the present invention has been described in detail only for the specific examples described above, it is obvious to those skilled in the art that various changes and modifications are possible within the scope of the technical idea of the present invention. Such variations and modifications are naturally within the scope of the claims.

Claims (5)

  1. 　三相中性点クランプ式の電力変換装置であって、
    　その制御回路は、
    　ｄ軸電流指令値とｄ軸電流検出値との偏差、および、ｑ軸電流指令値とｑ軸電流検出値との偏差に基づいてＰＩ制御を行う電流制御機能により、二相電圧指令値を演算する電流制御部と、
    　二相電圧指令値を三相電圧指令値に変換する二相三相変換部と、
    　直列接続された平滑コンデンサの電圧偏差を補償する中性点電位補償量を演算する中性点電位制御部と、
    　電力変換装置の運転開始時から予め設定された時間経過するまで制限補償量として中性点電位補償量を制限した値を出力し、電力変換装置の運転開始時から予め設定された時間経過後は制限補償量として中性点電位補償量をそのまま出力する制限手段と、
    　制限補償量と三相電圧指令値を加算し、補正電圧指令値を演算する加算部と、
    　補正電圧指令値が閾値を下回る場合、補正電圧指令値をそのままリミット処理電圧指令値として出力し、補正電圧指令値が閾値以上の場合、閾値をリミット処理電圧指令値として出力するリミッタと、
    　前記リミット処置電圧指令値に基づいてＰＷＭ制御をするＰＷＭ制御部と、を備えた三相中性点クランプ式の電力変換装置。     A three-phase neutral point clamp type power converter,
    The control circuit is
    Two-phase voltage command value is calculated by current control function that performs PI control based on deviation between d-axis current command value and d-axis current detection value, and deviation between q-axis current command value and q-axis current detection value Current controller to
    A two-phase three-phase converter for converting a two-phase voltage command value into a three-phase voltage command value;
    A neutral point potential control unit for calculating a neutral point potential compensation amount that compensates for voltage deviation of the smoothing capacitors connected in series;
    Output a value that limits the neutral point potential compensation amount as a limit compensation amount until a preset time has elapsed since the start of operation of the power converter, and after a preset time has elapsed since the start of the operation of the power converter Limiting means for directly outputting the neutral point potential compensation amount as the limit compensation amount;
    An addition unit for adding the limit compensation amount and the three-phase voltage command value and calculating a correction voltage command value;
    When the correction voltage command value is below the threshold value, the correction voltage command value is output as it is as the limit processing voltage command value, and when the correction voltage command value is equal to or greater than the threshold value, a limiter that outputs the threshold value as the limit processing voltage command value;
    A three-phase neutral point clamp type power converter comprising: a PWM control unit that performs PWM control based on the limit treatment voltage command value.
  2. 　前記制限手段は、
    　電力変換装置が運転を開始してから予め設定された時間経過するまで制限補償量を０とする請求項１記載の三相中性点クランプ式の電力変換装置。     The limiting means is
    The three-phase neutral point clamp type power converter according to claim 1, wherein the limit compensation amount is set to 0 until a preset time elapses after the power converter starts operation.
  3. 　前記制限手段は、
    　電力変換装置が運転開始するまで制限補償量を０とし、電力変換装置が運転開始してから予め設定された時間経過するまでの間に制限補償量を徐々に増加させる請求項１記載の三相中性点クランプ式の電力変換装置。     The limiting means is
    The three-phase according to claim 1, wherein the limit compensation amount is set to 0 until the power conversion device starts operation, and the limit compensation amount is gradually increased until a preset time elapses after the power conversion device starts operation. Neutral point clamp type power converter.
  4. 　前記電力変換装置の三相交流出力に接続する負荷はモータであり、
    　モータの位相検出値に基づいて三相電流検出値をｄ軸電流検出値，ｑ軸電流検出値に変換し、モータの位相検出値に基づいて二相電圧指令値を三相電圧指令値に変換する請求項１～３のうち何れかに記載の３相中性点クランプ式の電力変換装置。     The load connected to the three-phase AC output of the power converter is a motor,
    Based on the phase detection value of the motor, the three-phase current detection value is converted into the d-axis current detection value and the q-axis current detection value. Based on the phase detection value of the motor, the two-phase voltage command value is converted into the three-phase voltage command value. The three-phase neutral point clamp type power converter according to any one of claims 1 to 3.
  5. 　前記電力変換装置は系統に連系されており、系統位相の検出値に基づいて三相電流検出値をｄ軸電流検出値，ｑ軸電流検出値に変換し、系統位相の検出値に基づいて二相電圧指令値を三相電圧指令値に変換する請求項１～３のうち何れかに記載の３相中性点クランプ式の電力変換装置。 The power converter is connected to a grid, converts a three-phase current detection value into a d-axis current detection value and a q-axis current detection value based on the detection value of the system phase, and based on the detection value of the system phase. The three-phase neutral point clamp type power converter according to any one of claims 1 to 3, wherein the two-phase voltage command value is converted into a three-phase voltage command value.
PCT/JP2015/078447 2014-10-20 2015-10-07 Three-phase neutral point clamped power conversion device WO2016063724A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01298959A (en) * 1988-05-27 1989-12-01 Mitsubishi Electric Corp Pwm converter
JPH09172783A (en) * 1995-12-19 1997-06-30 Toshiba Corp Npc inverter
JPH09191656A (en) * 1996-01-09 1997-07-22 Hitachi Ltd Multilevel power converter
JP2003111433A (en) * 2001-09-27 2003-04-11 Mitsubishi Electric Corp Neutral point clamped 3-level inverter

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01298959A (en) * 1988-05-27 1989-12-01 Mitsubishi Electric Corp Pwm converter
JPH09172783A (en) * 1995-12-19 1997-06-30 Toshiba Corp Npc inverter
JPH09191656A (en) * 1996-01-09 1997-07-22 Hitachi Ltd Multilevel power converter
JP2003111433A (en) * 2001-09-27 2003-04-11 Mitsubishi Electric Corp Neutral point clamped 3-level inverter

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