JP4094412B2 - Power regeneration converter - Google Patents

Description

【００７２】
また、回生トランジスタＴｒ１〜Ｔｒ６の駆動信号の切換時間（次回相切換時間）の演算では、駆動信号の切り換えを行わない位相の相電圧位相検出信号の立ち上がり時間と立ち下がり時間の中間点の時刻を求めることを行う。これによって、例えば、回生トランジスタＴｒ１をオン動作からオフ動作に切り換え、回生トランジスタＴｒ３をオフ動作からオン動作に切り換えるタイミングは、Ｔ相電圧位相検出信号の立ち下がりから立ち上がりまでの中間点となる。
【００７３】
つまり、次回相切換時間は、時刻ｔｎ−１と時刻ｔｎ−４との中間時刻に電源周期の半周期を加えた次式（２）
次回相切換時間＝［｛（ｔｎ−１）＋（ｔｎ−４）｝／２］＋電源周期／２
…（２）
によって求めることができる。このようにして求められた電源周期と次回相切換時間とに基づき回生トランジスタＴｒ１〜Ｔｒ６の駆動信号が生成されるので（図８（５））、回生トランジスタＴｒ１〜Ｔｒ６は、本来のタイミングでオン・オフ動作することになる。
【００７４】
次に、図６に示す回生信号生成部２２が電源電圧波形検出部２１の検出波形に基づき電圧不平衡や高調波歪みに対する補正操作を行う構成について説明する。図９は、この発明の一実施の形態として図１に示す電源電圧波形検出部２１の構成例を示すブロック図である。
【００７５】
図９において、電源電圧波形検出部２１は、ダイオードＤ３１〜Ｄ３６による３相ブリッジ整流回路を備えている。この３相ブリッジ整流回路は、三相交流電源２からリアクトルＬＲ，ＬＳ，ＬＴを介して入力される三相電圧を整流する。この３相ブリッジ整流回路の“＋”“−”出力間には、抵抗器Ｒ４，Ｒ５の直列回路による抵抗分圧回路が接続され、整流された脈流波形電圧の分圧電圧が抵抗器Ｒ５の両端に現れる。抵抗器Ｒ５の両端電圧は、アンプ９１を介してＡ／Ｄ変換器９２に入力される。Ａ／Ｄ変換器９２は、３相ブリッジ整流回路にて整流された脈流電圧波形をサンプリングし、各サンプリング値（図１に示すＶｒｅｆ）を監視信号として図６に示す回生信号生成部２２のＭＰＵ６９に出力するようになっている。
【００７６】
つまり、ＭＰＵ６９は、電源電圧波形検出部２１からの電源電圧波形を常時監視し、電源電圧の不平衡（電圧のアンバランス、位相差のずれ）や電源電圧の高調波歪みを検出し、それに基づき回生トランジスタＴｒ１〜Ｔｒ６のオン・オフ動作タイミングを補正し、安定した電源回生動作が可能となるようにしている。以下、その補正操作を図１０と図１１を参照して具体的に説明する。
【００７７】
図１０は、図７に示す回生動作が行われるこの発明の一実施の形態である電源回生コンバータにおいて三相電圧に不平衡が生じた場合の回生動作を説明するタイムチャートである。
【００７８】
図８にて説明したように、ＭＰＵ６９は、例えば、Ｒ相の上アーム回生トランジスタＴｒ１とＳ相の上アーム回生トランジスタＴｒ３とのオン・オフ動作切換タイミングをＴ相電圧位相相検出信号の立ち下がりと立ち上がりとの中間点に定めている。
【００７９】
この場合、電源電圧に不平衡（電圧のアンバランス、位相差のずれ）が発生すると、上記のように定めた中間点と、電圧が最大または最小となる相の入れ替わり点との間にずれが生ずることになる。例えば、図１０は、Ｒ相電圧のみが高い場合を示すが、図１０（２）に示すように、Ｔ相電圧位相相検出信号の立ち下がりと立ち上がりとの中間点と、Ｒ相電圧とＳ相電圧との相入れ替わり点との間に時間ｔ０のずれが生ずる。
【００８０】
そこで、ＭＰＵ６９は、図１０（３）に示すように、電源電圧波形検出部２１からの電源電圧波形における電圧最大値の切り替わり位相を常時監視し、上記のようなずれを検出すると、そのずれ量を記憶し、回生トランジスタＴｒ１〜Ｔｒ６に与える駆動信号の変化タイミングを補正し、コンパレータ６８に出力する。
【００８１】
その結果、電源電圧に不平衡が発生している場合でも、図１０（４）に示すように、電圧が最大または最小となる相の入れ替わりタイミングと回生トランジスタＴｒ１〜Ｔｒ６のオン・オフ動作タイミングとを常に一致させることができ、電圧の最も高い相に回生電流を流すことができるようになる（図１０（５））。
【００８２】
次に、図１１は、図７に示す回生動作が行われるこの発明の一実施の形態である電源回生コンバータにおいて三相電圧に高調波歪みが生じた場合の回生動作の停止判断を説明するタイムチャートである。
【００８３】
図１１（１）では、三相電圧に高調波歪みが生じている様子が示されている。上記のように、ＭＰＵ６９は、電源電圧波形検出部２１からの電源電圧波形に基づき線間電圧の最も高くなる位相が検出できる。
【００８４】
そこで、ＭＰＵ６９は、直流母線１６，１７の電圧が低下すると、図１１（２）に示すように、検出した最も線間電圧の高くなる位相において回生電流検出器１９が検出する回生電流を監視する。そして、回生動作停止用の回生電流サンプリング位相（図１１（３）に示す＊印）を回生電流が最も小さくなる位相に補正し、回生停止判断を行う。
【００８５】
その結果、図１１（１）に示すように電源波形歪がある場合でも安定した回生動作の停止制御が行える。なお、三相電圧に不平衡がある場合にも、前記と同様に電圧の低い相では回生停止判断を行わないようにすることができるので、安定した回生制御が行える。
【００８６】
なお、三相電圧に不平衡がある場合や高調波歪みが発生している場合の補正操作は、線間電圧のゼロクロス点検出による従来の電圧位相検出方式においても同様に適用できることは言うまでもない。
【００８７】
【発明の効果】
以上説明したように、この発明によれば、相電圧の入れ替わりタイミングにずれを検出したとき、すなわち、三相電圧に不平衡があるときは、その不平衡状態に合わせて回生トランジスタのオン・オフ駆動信号の変化タイミングを補正することができるので、三相電圧に不平衡があるときでも正常に電源回生が行えるようになる。
【００８８】
つぎの発明によれば、平滑コンデンサの端子電圧が低下した場合において電圧が最大となる位相の回生電流を利用して回生動作の停止判断を行うので、電源電圧に高調波歪みが発生している場合でも安定して回生動作とその停止が行えるようになる。
【００８９】
つぎの発明によれば、三相交流電源の相電圧のゼロクロス検出によって検出した電圧位相の変化タイミングと回生トランジスタのオン・オフ動作タイミングとを異ならせることができる。したがって、回生トランジスタのオン・オフ動作に起因して発生するスパイク状の歪み電圧の影響を受けずに安定して電源位相の検出が行えるようになる。
【図面の簡単な説明】
【図１】 この発明を適用とする電源回生コンバータの構成例を示すブロック図である。
【図２】 図１に示す電源回生コンバータでの回生動作の開始と停止を説明するタイムチャートである。
【図３】 図１に示す電源回生コンバータで一般的に行われている回生動作を説明するタイムチャートである。
【図４】 図３に示す一般的な回生動作が行われる電源回生コンバータにおいて三相電圧に不平衡が生じた場合の回生動作を説明するタイムチャートである。
【図５】 図３に示す一般的な回生動作が行われる電源回生コンバータにおいて三相電圧に高調波歪みが生じた場合の回生動作を説明するタイムチャートである。
【図６】 この発明の一実施の形態として図１に示す位相検出部および回生信号生成部の構成例を示すブロック図である。
【図７】 図６に示す位相検出部および回生信号生成部を備えたこの発明の一実施の形態である電源回生コンバータでの回生動作を説明するタイムチャートである。
【図８】 図６に示す回生信号生成部の回生信号生成動作を説明するタイムチャートである。
【図９】 この発明の一実施の形態として図１に示す電源電圧波形検出部の構成例を示すブロック図である。
【図１０】 図７に示す回生動作が行われるこの発明の一実施の形態である電源回生コンバータにおいて三相電圧に不平衡が生じた場合の回生動作を説明するタイムチャートである。
【図１１】 図７に示す回生動作が行われるこの発明の一実施の形態である電源回生コンバータにおいて三相電圧に高調波歪みが生じた場合の回生動作の停止判断を説明するタイムチャートである。
【符号の説明】
１ 電源回生コンバータ、２ 三相交流電源、３ 三相誘導電動機（モータ）、４ インバータ装置、５ リアクトル（ＬＲ、ＬＳ、ＬＴ）、１１〜１３ 交流電源端子、１４，１５ 直流電源端子、１６，１７ 直流母線、１８ 直流電圧検出部、１９ 回生電流検出器、２０ 位相検出部、２１ 交流電圧波形検出部、２２ 回生信号生成部、Ｃ 平滑コンデンサ、Ｔｒ１，Ｔｒ２，Ｔｒ３，Ｔｒ４，Ｔｒ５，Ｔｒ６ 回生トランジスタ、Ｄ１〜Ｄ６ ダイオード、ＯＩ１，ＯＩ２，ＯＩ３ ホトカプラ、６６ タイマー、６７ ラッチ回路、６８ コンパレータ、６９ マイクロ・プロセッサ・ユニット（ＭＰＵ）、Ｄ３１〜Ｄ３６３相ブリッジ整流回路を構成するダイオード、Ｒ４，Ｒ５ 抵抗分圧回路を構成する抵抗器、９２ Ａ／Ｄ変換器。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power regeneration converter.
[0002]
[Prior art]
A power regeneration converter is a device that is arranged between an inverter device that controls a three-phase induction motor at variable speed and a three-phase AC power source, and that regenerates the induced electromotive force generated when the three-phase induction motor decelerates to the three-phase AC power source. is there.
[0003]
This power regenerative converter is provided with six smoothing capacitors provided in parallel to a smoothing capacitor connected to a group of full-wave rectifier diodes in the inverter device and three upper arms and three lower arms. And a control circuit that controls on / off of the six regenerative transistors.
[0004]
The smoothing capacitor is charged with a DC voltage rectified by a full-wave rectifier diode group during powering of the three-phase induction motor. When the terminal voltage of the smoothing capacitor rises due to the induced electromotive force generated when the three-phase induction motor decelerates and becomes higher than the voltage of the three-phase AC power supply, the control circuit connects the six regenerative transistors to the voltage phase of the three-phase AC power supply. The power stored in the smoothing capacitor is regenerated to the three-phase AC power source.
[0005]
Here, conventionally, the on / off operation relationship of the six regenerative transistors is synchronized with the voltage phase of the three-phase AC power supply as follows. That is, in the control circuit, based on the phase detection signal generated by the zero-crossing point detection of the line voltage of the three-phase AC power supply and the detection voltage of the three-phase AC power supply, the voltage among the three upper arms and the three lower arms The regenerative transistor of the upper arm connected to the largest phase and the regenerative transistor of the lower arm connected to the smallest phase are turned on, and the others are turned off, and the corresponding regenerative transistor is given a drive signal to turn off. (For example, Patent Document 1).
[0006]
[Patent Document 1]
JP 2000-253686A (0018-0021, FIG. 1)
[0007]
[Problems to be solved by the invention]
However, in the conventional power regeneration converter, the change timing of the phase detection signal coincides with the on / off operation timing of the regeneration transistor, so that the spike-like distortion voltage generated due to the on / off operation of the regeneration transistor. In some cases, the detection of the power supply phase is erroneous due to the influence of the above, and the operation is unstable, for example, the regenerative transistor is erroneously turned on.
[0008]
In addition, when an unbalance occurs in the phase voltage of the three-phase AC power supply, a shift occurs between the change timing of the drive signal and the switching timing of the phase voltage (zero cross point of the line voltage). In this case, conventionally, since the regenerative transistor is turned on even at a large voltage difference between the power supply voltage and the DC bus voltage, an excessive regenerative current flows.
[0009]
In addition, when the regenerative energy is small, the regenerative current is close to zero near the peak of the power supply voltage phase, and the regenerative current at the phase where the line voltage is maximum is monitored. However, if harmonic distortion occurs in the power supply voltage, conventionally, there is a case where the regenerative stop determination is erroneous and the regenerative operation is not stopped.
[0010]
The present invention has been made in view of the above, and can detect the voltage phase of the three-phase AC power supply with a phase shifted from the on / off operation timing of the regenerative transistor, and can detect unbalance and harmonic distortion in the voltage of the three-phase AC power supply. An object of the present invention is to obtain a power regeneration converter having means for correcting the on / off operation timing of a regeneration transistor.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, a power regenerative converter according to the present invention is disposed between a three-phase AC power supply and a control device for variable-speed control of the three-phase induction motor, and detects a voltage phase of the three-phase AC power supply. A phase detection unit, a regenerative transistor that switches a terminal voltage of a smoothing capacitor that accumulates an induced electromotive force generated when the three-phase induction motor decelerates and performs a power regenerative operation on the three-phase AC power source, and an on-state of the regenerative transistor In a power regeneration converter including a regeneration signal generation unit that generates an off drive signal based on a detection signal of the phase detection unit, the regeneration signal generation unit monitors a voltage waveform of the three-phase AC power source, Maximum or minimum Phase voltage But Replaced Ru timing And an intermediate position between the voltage phase change points detected by the phase detection means, When the deviation is detected, the change timing of the on / off drive signal given to the regenerative transistor is When the phase voltage changes It is characterized by correcting.
[0012]
According to this invention, Maximum or minimum Phase voltage But Replaced Ru timing And the intermediate position between the voltage phase change points detected by the phase detection means Is detected, that is, when there is an imbalance in the three-phase voltage, the change timing of the on / off drive signal of the regenerative transistor is adjusted according to the unbalanced state. When the phase voltage changes It can be corrected.
[0013]
A power regenerative converter according to the next invention is arranged between a three-phase AC power supply and a control device for variable-speed control of the three-phase induction motor, phase detection means for detecting a voltage phase of the three-phase AC power supply, A regenerative transistor that performs a power regenerative operation on the three-phase AC power source by switching a terminal voltage of a smoothing capacitor that accumulates an induced electromotive force generated at the time of deceleration of the three-phase induction motor, and an on / off drive signal of the regenerative transistor In the power regeneration converter including the regeneration signal generation means that generates based on the detection signal of the phase detection means, the regeneration signal generation means monitors the voltage waveform of the three-phase AC power supply, and the terminal voltage of the smoothing capacitor decreases. In this case, the phase at which the voltage of the three-phase AC power supply is maximum is detected, and the regenerative current sampling phase for stopping the regenerative operation is detected. To the phase where the regenerative current becomes the smallest It is characterized by correcting.
[0014]
According to the present invention, when the terminal voltage of the smoothing capacitor is lowered, the regenerative operation is determined to be stopped using the regenerative current of the phase where the voltage becomes the maximum, so that the harmonic distortion occurs in the power supply voltage. However, the regenerative operation can be stopped and stopped stably.
[0015]
In the power regeneration converter according to the next invention, in the above invention, the regeneration signal generating means outputs an on / off drive signal to be supplied to the regeneration transistor, and the phase detecting means converts the voltage phase of the three-phase AC power supply into a phase voltage. Based on the intermediate position between the voltage phase change points detected by zero cross detection So that the line voltage difference of the three-phase AC power supply changes to zero. It is characterized by generating.
[0016]
According to this invention, the three-phase AC power source Phase of Detected by voltage zero cross detection Voltage phase Change timing When Regenerative transistor on / off operation timing and The Can be different.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Exemplary embodiments of a power regeneration converter according to the present invention will be explained below in detail with reference to the accompanying drawings.
[0018]
FIG. 1 is a block diagram showing a configuration example of a power regeneration converter to which the present invention is applied. As shown in FIG. 1, a power regeneration converter 1 includes a three-phase AC power source 2 that generates a three-phase (R-phase, S-phase, and T-phase) AC voltage, and a three-phase induction motor (hereinafter referred to as “motor”) 3. Is arranged between the inverter device 4 for variable speed control. In FIG. 1, the connection line between the three-phase AC power source 2 and the inverter device 4 is not shown.
[0019]
The power regeneration converter 1 includes AC power supply terminals 11, 12, and 13. Each power supply terminal of the three-phase AC power supply 2 is connected to AC power supply terminals 11, 12, and 13 via a reactor (LR, LS, LT) 5. Further, the power regeneration converter 1 includes DC power supply terminals 14 and 15. The DC power supply terminals 14 and 15 are connected to a DC bus in the inverter device 4.
[0020]
In the power regeneration converter 1, DC buses 16 and 17 connected to the DC power supply terminals 14 and 15 are arranged, and a smoothing capacitor C is connected between the DC buses 16 and 17. Both ends of the smoothing capacitor C are connected to the DC voltage detector 18. A regenerative current detector 19 is disposed on the DC bus 16.
[0021]
Between the DC buses 16 and 17, three sets of regenerative transistors Tr1 and Tr2, regenerative transistors Tr3 and Tr4, and regenerative transistors Tr5 and Tr6 connected in series are connected in parallel. That is, the collector terminals of the regenerative transistors Tr1, Tr3, Tr5 constituting the upper arm are connected between the DC buses 16, and the emitter terminals of the regenerative transistors Tr2, Tr4, Tr6 constituting the lower arm are connected to the DC bus 17. It is connected.
[0022]
The emitter terminal of the regenerative transistor Tr1 and the collector terminal of the regenerative transistor Tr2 are connected to the AC power supply terminal 11 in common. The emitter terminal of the regeneration transistor Tr3 and the collector terminal of the regeneration transistor Tr4 are connected to the AC power supply terminal 12 in common. The emitter terminal of the regeneration transistor Tr5 and the collector terminal of the regeneration transistor Tr6 are connected to the AC power supply terminal 13 in common. Note that diodes D1 to D6 are connected in parallel to these regenerative transistors. That is, the anode terminal of the diode is connected to the emitter terminal of the regenerative transistor, and the cathode terminal of the diode is connected to the collector terminal of the regenerative transistor.
[0023]
The AC power supply terminals 11, 12, and 13 are connected to a power supply phase detector 20 and an AC voltage waveform detector 21, and each output terminal of the power supply phase detector 20 and the AC voltage waveform detector 21 has a regenerative signal. The generator 22 is connected. The output terminal of the DC voltage detector 18 and the output terminal of the regenerative current detector 19 are also connected to the regenerative signal generator 22. The six output terminals of the regeneration signal generator 22 are connected to corresponding base terminals of the regeneration transistors Tr1, Tr2, Tr3, Tr4, Tr5, Tr6.
[0024]
In the above configuration, in order to facilitate understanding of the present invention, FIG. 5 The general operation of the power regeneration converter will be described with reference to FIG. FIG. 2 is a time chart for explaining the start and stop of the regenerative operation in the power regeneration converter shown in FIG. FIG. 3 is a time chart for explaining the regenerative operation generally performed in the power regeneration converter shown in FIG. FIG. 4 is a time chart for explaining the regenerative operation when an unbalance occurs in the three-phase voltage in the power regeneration converter in which the general regenerative operation shown in FIG. 3 is performed. FIG. 5 is a time chart for explaining the regenerative operation when harmonic distortion occurs in the three-phase voltage in the power regeneration converter in which the general regenerative operation shown in FIG. 3 is performed.
[0025]
1 and 2, the regenerative operation is started as follows. As shown in FIG. 2 (1), the AC voltage waveform detector 21 has a peak value V of the three-phase AC power supply 2. _pr-s Is detected and the power supply voltage peak value Vr is detected. e This is output to the regenerative signal generator 22 as f. On the other hand, the DC voltage detector 18 detects the terminal voltage of the smoothing capacitor C, that is, the voltages of the DC buses 16 and 17, and outputs the detected DC bus voltage Vpn to the regenerative signal generator 22. Further, the phase detector 20 detects the voltage phase of the three-phase AC power supply 2 and outputs it to the regenerative signal generator 22. Note that the phase detector 20 conventionally detects an interphase voltage phase by detecting a zero-cross point of the line voltage.
[0026]
When the deceleration control of the motor 3 is performed, a current due to the generated induced electromotive force flows into the smoothing capacitor C, and the terminal voltage of the smoothing capacitor C increases. As a result, the terminal voltage of the smoothing capacitor C becomes higher than the voltage of one phase of the three phases (R phase, S phase, T phase) of the three-phase AC power supply 2, and the terminal voltage of the smoothing capacitor C and the three-phase AC A voltage difference is generated between the voltage of the power source 2.
[0027]
Therefore, in the regenerative signal generation unit 22, FIG. 2 ), The power supply voltage peak value Vref detected by the AC voltage waveform detector 21 is compared with the DC bus voltage value Vpn detected by the DC voltage detector 18, and the DC bus voltage value Vpn is When the voltage peak value Vref becomes higher, drive signals (regenerative signals) for the regenerative transistors Tr1 to Tr6 are generated based on the phase detection signal from the phase detector 20, and the on / off control operation of the regenerative transistors Tr1 to Tr6 is performed. To start. The contents of the on / off control operation of the regenerative transistors Tr1 to Tr6 will be described later (FIG. 3).
[0028]
As a result, a three-phase regenerative current is generated from the smoothing capacitor C to the three-phase AC power source 2 through the regenerative transistors Tr1 to Tr6, the power supply terminals 11 to 13, and the reactor 5 (FIG. 2 (3)). The regenerative current detector 19 detects a bus current flowing through the DC bus 16 and outputs a regenerative current detection signal Ipn to the regenerative signal generator 22. When the power regeneration is started, a large-amplitude regenerative current is detected as shown on the left side of FIG.
[0029]
Next, the regeneration operation is stopped as follows. When the power regeneration operation is started, even if the motor is decelerating, only a difference corresponding to the ON voltage of the regeneration transistor occurs between the DC bus voltage value Vpn and the power supply voltage peak value Vref, and the voltage difference becomes extremely small. . As a result, if the regeneration stop is determined only by the decrease in the DC bus voltage value Vpn, the regeneration is frequently started and stopped repeatedly, and the regeneration operation is intermittently performed, so that the operation becomes unstable.
[0030]
In view of this, the regenerative signal generation unit 22 determines the stop timing of the regenerative operation from the regenerative current detection signal Ipn and the DC bus voltage value Vpn. Specifically, when the regenerative current from the motor decreases, that is, when the regenerative energy decreases, the regenerative current (regenerative current detection signal Ipn) of the power regeneration converter 1 is as shown on the right side of FIG. The current approaches zero near the peak of the power supply voltage phase. By utilizing this, the regenerative current is monitored at the phase where the voltage value of the line voltage is maximum, that is, at the time indicated by * shown on the right side of FIG. 2 (4), and the regenerative current detection signal Ipn is a predetermined value. When it becomes below, the on / off control operation of the regenerative transistors Tr1 to Tr6 is stopped.
[0031]
Next, the operation during power regeneration will be described with reference to FIG. 1 and FIG. As described above, the power regeneration is performed using the voltage difference between the terminal voltage of the smoothing capacitor C and the voltage of the three-phase AC power supply 2 and the regenerative current is limited by the reactor 5, so that the on / off operation is performed. If the phase of the regenerative transistor is incorrect, the voltage difference becomes large and a large current flows rapidly, which may cause the device to stop or be damaged. Therefore, the detection of the power supply phase and the on / off control of the regenerative transistors Tr1 to Tr6 are performed as follows.
[0032]
As shown in FIG. 3B, the phase detection unit 20 detects a zero cross point of the line voltage, and between the zero cross points, a high level (hereinafter referred to as “H level”) and a low level (hereinafter referred to as “L level”). And a phase detection signal that alternately changes. That is, the voltage phase detection signal between R and S maintains the “H” level during the period when the R phase voltage−S phase voltage> 0, and when the R phase voltage−S phase voltage = 0, Although the level falls to the level and the R-phase voltage-S-phase voltage <0, the "L" level is maintained, and although not shown, when the R-phase voltage-S-phase voltage = 0 next, "H""A signal that rises to a level and repeats this. The same applies to the ST voltage phase detection signal and the TR voltage phase detection signal.
[0033]
Regarding the on / off control of the regenerative transistors Tr1 to Tr6, the upper arm regenerative transistors Tr1, Tr3, Tr5 must be turned on in the maximum voltage phase among the three-phase (R phase, S phase, T phase) voltages. There is. Conversely, the lower arm regenerative transistors Tr2, Tr4, Tr6 must be turned on in the phase of the minimum voltage among the three-phase voltages. Then, it is necessary to switch the on / off operation relationship at the zero cross point of the line voltage where the phase voltage is switched.
[0034]
Therefore, the regenerative signal generation unit 22 has three line voltage phase detection signals (FIG. 3 (2)) from the phase detection unit 20 and the power supply voltage peak value Vref from the AC voltage waveform detection unit 21. Of the upper arm and the three lower arms, the upper arm regenerative transistor connected to the phase with the highest voltage and the lower arm regenerative transistor connected to the phase with the lowest voltage are turned on, and the others are turned off. The regenerative signal to be applied is supplied to the corresponding regenerative transistor.
[0035]
As a result, the regenerative transistors Tr1 to Tr6 perform an on operation and an off operation according to the relationship shown in FIG. In the upper arm regenerative transistors Trl, Tr3, Tr5, the regenerative transistor Trl is within a period in which the R-phase voltage is maximum, that is, from the time t10 when the R-phase voltage> T-phase voltage is satisfied, The ON operation is performed during the period up to t50. The regenerative transistor Tr3 performs an ON operation within a period in which the S-phase voltage is maximum, that is, from a time t50 when the S-phase voltage> the R-phase voltage to a time t90 when the S-phase voltage <the T-phase voltage. The regenerative transistor Tr5 performs an on-operation within a period in which the T-phase voltage is maximum, that is, from a time t90 when T-phase voltage> S-phase voltage to a time t10 when T-phase voltage <R-phase voltage.
[0036]
Further, in the lower-arm regenerative transistors Tr2, Tr4, Tr6, the regenerative transistor Tr2 is within the period in which the R-phase voltage is minimum, that is, the R-phase voltage> S-phase voltage from time t70 when the R-phase voltage <T-phase voltage The ON operation is performed within a period until time t110. The regenerative transistor Tr4 performs an ON operation within a period in which the S phase voltage is minimum, that is, from a time t110 when the S phase voltage <R phase voltage is reached to a time t30 when the S phase voltage> T phase voltage. The regenerative transistor Tr6 performs an ON operation within a period in which the T-phase voltage is minimum, that is, from a time t30 when the T-phase voltage <S-phase voltage is reached to a time t70 when the T-phase voltage> R-phase voltage.
[0037]
That is, during the period from time t10 to time t50 when the upper arm regenerative transistor Trl is turned on, the lower arm regenerative transistor Tr4 is turned on during the period from time t10 to time t30, and from time t30 to time t30. During the period up to t50, the regenerative transistor Tr6 of the lower arm is on. During the period from time t50 to time t90 when the upper arm regenerative transistor Tr3 is turned on, the lower arm regenerative transistor Tr6 is turned on during the period from time t50 to time t70, and from time t70 to time t90. During this period, the regenerative transistor Tr2 of the lower arm is on. Within the period from time t90 to time t10 when the upper arm regenerative transistor Tr5 is turned on, the lower arm regenerative transistor Tr2 is turned on during the period from time t90 to time t110, and from time t110 to time t10. During this period, the regenerative transistor Tr4 of the lower arm is on.
[0038]
As a result, the regenerative current (R phase, S phase, T phase) having a pulse waveform as shown in FIG. 3 (4) is changed from the smoothing capacitor C to the regenerative transistors Tr1 to Tr6 to the reactor 5 (LR, LS, LT) → three. It flows with the phase AC power supply 2.
[0039]
Here, a spike-like distortion voltage is generated in the voltage of the three-phase AC power supply 2 due to the on / off operation of the regenerative transistors Tr1 to Tr6. As can be understood from FIGS. The change timing of the inter-phase voltage phase detection signal coincides with the on / off operation timing of the regenerative transistors Tr1 to Tr6. Therefore, the phase detection unit 20 that detects the phase of the line voltage may erroneously detect the power supply phase, and the regenerative signal generation unit 22 may erroneously turn on the regenerative transistors Tr1 to Tr6. Conventionally, measures for connecting the power input terminal of the phase detector 20 between the reactor 5 and the three-phase AC power source 2 and measures for adding a current limiting resistor have been taken as countermeasures.
[0040]
Also, as shown in FIG. 4A, for example, when an unbalance occurs such that the R phase voltage is higher than the other phase voltages, the phase detection unit 20 that detects the phase of the line voltage detects the normal state. It occurs that a position shifted by time t from the zero cross point is detected as a zero cross point. As a result, in the regenerative signal generation unit 22, as shown in FIGS. 4 (2) and (3), the regenerative transistor is turned on even in a place where the voltage difference between the power supply voltage and the DC bus voltage is large. As shown in (), a phenomenon in which the regenerative current becomes excessive appears.
[0041]
In addition, when determining whether to stop the regenerative operation, if the power supply voltage has a harmonic distortion as shown in FIG. 5 (1), the regenerative current changes to a waveform as shown in FIG. 5 (2). To do. Then, if the regenerative stop determination is made with the current value sampled at the position of * in the figure, the regenerative stop determination may be wrong and the regenerative operation may not stop.
[0042]
Therefore, in the present invention, the phase detection unit 20 is configured to be able to detect the power supply phase at a phase that excludes the on / off operation timing of the regenerative transistor, and the regenerative signal generation unit 22 is in the state of power supply unbalance or harmonic distortion. It is comprised so that correction | amendment operation can be performed with respect to. This will be specifically described below.
[0043]
FIG. 6 is a block diagram showing a configuration example of the phase detection unit and the regenerative signal generation unit shown in FIG. 1 as one embodiment of the present invention. FIG. 7 is a time chart for explaining the regenerative operation in the power regeneration converter according to the embodiment of the present invention including the phase detector and the regenerative signal generator shown in FIG. FIG. 8 is a time chart for explaining the regeneration signal generation operation of the regeneration signal generation unit shown in FIG.
[0044]
In FIG. 6, the phase detection unit 20 according to this embodiment includes phase detection photocouplers OI 1, OI 2, and OI 3, and outputs a phase detection signal based on zero-cross point detection of each phase voltage to the regenerative signal generation unit 22. It has become.
[0045]
The light-emitting diode of the photocoupler OI1 has an anode connected to the R-phase AC power supply terminal 11 through a current limiting resistor R1. In addition, a diode D11 is connected in reverse parallel to the light emitting diode. The light-emitting diode of the photocoupler OI2 has an anode connected to the S-phase AC power supply terminal 12 via a current limiting resistor R2. A diode D12 is connected in antiparallel to the light emitting diode. The light-emitting diode of the photocoupler OI3 has an anode connected to the T-phase AC power supply terminal 13 via a current limiting resistor R3. A diode D13 is connected in antiparallel to the light emitting diode.
[0046]
The cathodes of the light emitting diodes of the photocouplers OI1, OI2, and OI3 are connected to each other. The phototransistor of the photocoupler OI1 has an emitter terminal connected to the ground and a collector terminal connected to the regenerative signal generator 22 via the inverter 61. A connection line between the collector terminal and the inverter 61 is connected to a power source via a pull-up resistor R11.
[0047]
The phototransistor of the photocoupler OI2 has an emitter terminal connected to the ground and a collector terminal connected to the regenerative signal generator 22 via the inverter 62. A connection line between the collector terminal and the inverter 62 is connected to the power supply via the pull-up resistor R12. The phototransistor of the photocoupler OI3 has an emitter terminal connected to the ground and a collector terminal connected to the regenerative signal generator 22 via the inverter 63. The connection line between the collector terminal and the inverter 63 is Not marked Pull-up resistor Vessel Connected to the power supply.
[0048]
According to the configuration of the phase detection unit 20 according to this embodiment, if the voltage drops of the photocouplers OI1, OI2, OI3 and the diodes D11, D12, D13 are ignored, the circuit is connected to the three-phase AC power source 2 by resistors R1, R2, Since it is a circuit in which R3 is star-connected, a three-phase sine wave alternating current flows. Accordingly, the R-phase, S-phase, and T-phase voltage phase detection signals that are the outputs of the photocouplers OI1, OI2, and OI3 are determined by the direction of the three-phase sinusoidal alternating current.
[0049]
That is, the photocoupler OI1 is turned on when the R-phase voltage of the three-phase AC power supply 2 is “+”, and the input level of the inverter 61 is set to the “L” level. The photocoupler OI1 performs an off operation when the R-phase voltage is “−”, and sets the input level of the inverter 61 to the “H” level. Therefore, the inverter 61 outputs an R-phase voltage phase detection signal that becomes “H” level during the period in which the R-phase voltage is “+” to the regenerative signal generator 22.
[0050]
The photocoupler OI2 is turned on when the S-phase voltage of the three-phase AC power supply 2 is “+”, and sets the input level of the inverter 62 to the “L” level. The photocoupler OI2 performs an off operation when the S-phase voltage is “−”, and sets the input level of the inverter 62 to the “H” level. Therefore, the inverter 62 outputs the S phase voltage phase detection signal that is at the “H” level during the period in which the S phase voltage is “+” to the regenerative signal generation unit 22.
[0051]
The photocoupler OI3 is turned on when the T-phase voltage of the three-phase AC power supply 2 is “+”, and sets the input level of the inverter 63 to the “L” level. The photocoupler OI3 performs an off operation when the T-phase voltage is “−”, and sets the input level of the inverter 63 to the “H” level. Therefore, the inverter 63 outputs a T-phase voltage phase detection signal that is at the “H” level during the period in which the T-phase voltage is “+” to the regenerative signal generation unit 22.
[0052]
Therefore, the respective phase voltages of the three-phase AC power supply 2 with respect to the neutral point and the R phase, S phase, and T phase voltage phase detection signals output from the phase detection unit 20 shown in FIG. 7 (1) and (2).
[0053]
That is, the R-phase voltage changes from “−” to “+” at time t00, and changes from “+” to “−” at time t60. Since the current flowing through the resistor R1 of the phase detector 20 has the same waveform, the R-phase voltage phase detection signal also changes from the “L” level to the “H” level at time t00, and from the “H” level to “ It changes to L ”level.
[0054]
The S-phase voltage changes from “−” to “+” at time t40, and changes from “+” to “−” at time t100. Since the current flowing through the resistor R2 of the phase detector 20 has the same waveform, the S-phase voltage phase detection signal also changes from “L” level to “H” level at time t40, and from “H” level to “H” level at time t100. It changes to L ”level.
[0055]
Similarly, the T-phase voltage changes from “+” to “−” at time t20, and changes from “−” to “+” at time t80. Since the current flowing through the resistor R3 of the phase detector 20 also has the same waveform, the T-phase voltage phase detection signal also changes from “H” level to “L” level at time t20, and from “L” level to “H” at t80. "Change to level.
[0056]
Here, since the regenerative transistors Tr1 to Tr6 need to be turned on / off according to the timing relationship described in FIG. 3 (3), the regenerative signal generator 22 shown in FIG. In response to the phase voltage phase signal shown in FIG. 7 (2), as shown in FIG. 7 (3), the regenerative transistors Tr1 to Tr6 are turned on / off in the same timing relationship as explained in FIG. 3 (3). A drive signal for turning off is generated.
[0057]
That is, in FIG. 7 (3), the regenerative transistor Tr1 has a maximum R-phase voltage, that is, from time t10 when R-phase voltage> T-phase voltage to time t50 when R-phase voltage <S-phase voltage. Turns on during the period. The regenerative transistor Tr2 performs an on-operation within a period in which the R-phase voltage is minimum, that is, from a time t70 when the R-phase voltage <T-phase voltage to a time t110 when the R-phase voltage> S-phase voltage. The regenerative transistor Tr3 performs an ON operation within a period in which the S-phase voltage is maximum, that is, from a time t50 when the S-phase voltage> the R-phase voltage to a time t90 when the S-phase voltage <the T-phase voltage.
[0058]
The regenerative transistor Tr4 performs an ON operation within a period in which the S phase voltage is minimum, that is, from a time t110 when the S phase voltage <R phase voltage is reached to a time t30 when the S phase voltage> T phase voltage. The regenerative transistor Tr5 performs an on-operation within a period in which the T-phase voltage is maximum, that is, from a time t90 when T-phase voltage> S-phase voltage to a time t10 when T-phase voltage <R-phase voltage. The regenerative transistor Tr6 performs an ON operation within a period in which the T-phase voltage is minimum, that is, from a time t30 when the T-phase voltage <S-phase voltage is reached to a time t70 when the T-phase voltage> R-phase voltage.
[0059]
As can be understood from FIGS. 7 (2) and 7 (3), the change point of the phase voltage phase detection signal generated by the phase detector 20 shown in FIG. 6 is the timing at which none of the regenerative transistors Tr1 to Tr6 performs the switching operation. ing. Therefore, the phase detection unit 20 shown in FIG. 6 can perform phase detection without being affected by the spike-like distortion voltage generated when the regenerative transistors Tr1 to Tr6 are switched on / off.
[0060]
Further, since the phase voltage phase detection signal has a changing point within a period during which the transistor of the phase to be detected is performing the off operation, the phase cannot be detected by the regenerative operation. For example, at time t00 in FIG. 7 (3), the regenerative transistors Tr4 and Tr5 are turned on, so that the LS terminal voltage and the LT terminal voltage of the reactor 5 change with respect to the original power supply voltage. However, the LR terminal voltage of the reactor 5 is not changed. Therefore, the phase detection of the R phase voltage can be performed normally. Thus, according to this embodiment, measures for connecting the power input terminal of the phase detector 20 between the reactor 5 and the three-phase AC power source 2 and measures for adding a current limiting resistor are unnecessary. It can be.
[0061]
Next, the regenerative signal generator 22 shown in FIG. 6 can perform a correction operation for voltage imbalance and waveform distortion in the process of controlling the on / off operation relationship of the regenerative transistors Tr1 to Tr6 at the original timing as described above. It is configured as follows. First, a configuration in which the regenerative transistors Tr1 to Tr6 are turned on / off at the original timing as described above will be described.
[0062]
In FIG. 6, in the regenerative signal generation unit 22, the outputs of the inverters 61, 62, and 63 of the phase detection unit 20 (phase detection signals of each phase voltage) MPU ”). In the exclusive OR circuit 65, one of the input three-phase phase voltage phase detection signals changes. The Detect time. The output of the exclusive OR circuit 65 is input to the latch circuit 67 as a control signal.
[0063]
The timer 66 is a free-run count type timer that generates a timer value that serves as a reference for generating a regenerative signal. The timer value is input to the comparator 68, the latch circuit 67, and the MPU 69.
[0064]
The latch circuit 67 latches the timer value of the timer 66 when one of the three phase voltage phase detection signals output from the exclusive OR circuit 65 changes, and holds and outputs the value to the MPU 69. Thereby, the MPU 69 can know the time when the power supply phase changes.
[0065]
MPU69 is a three-phase voltage phase detection From the signal and the timer value from the timer 66 at the changed time, the power cycle and the time (next phase switching time) when the regenerative transistors Tr1 to Tr6 are turned on / off next are calculated, and the calculated time is the regenerative transistor. It outputs to the comparator 68 as ON / OFF command value of Tr1-Tr6.
[0066]
The comparator 68 includes six comparators corresponding to the regenerative transistors Tr1 to Tr6. When the on / off command value matches the timer value from the timer 66, the comparator 68 outputs drive signals to the regenerative transistors Tr1 to Tr6. Change.
[0067]
With reference to FIG. 8, the calculation contents in the MPU 69 will be specifically described. Of the output of the timer 66 (FIG. 8 (3)), the timer value at the time when any of the three-phase phase voltage phase detection signals (FIG. 8 (2)) changes is held in the latch circuit 67 and stored in the MPU 69. It is taken in and stored one by one (FIG. 8 (4)).
[0068]
In FIG. 8 (4), the timer values tn-12, tn-11,..., Tn-n, tn are accumulated at each change time of the three-phase phase voltage phase detection signal (FIG. 8 (2)). It is shown. Based on the stored timer value (FIG. 8 (4)) and the three-phase phase voltage phase detection signal (FIG. 8 (2)) input from the phase detector 20, the MPU 69 performs the power cycle as follows. And the next phase switching time are calculated.
[0069]
That is, in the phase detection unit 20 shown in FIG. 6, the zero-cross points of the respective phases are detected by the photocouplers OI1, OI2, and OI3, and the phase voltage phase detection signal that changes positively and negatively is output. Due to the influence of the variation in the transmission rate and the like, there is a difference between the change timing of the phase voltage phase detection signal and the actual positive / negative change timing of the power supply voltage.
[0070]
Therefore, in order to prevent the MPU 69 from being affected by this timing shift, the power supply cycle is calculated by the time of the interval between the same edges in the same phase. For example, it is calculated by the time from the rising edge of the current R-phase voltage to the rising edge of the previous R-phase voltage. Specifically, the influence of the detection error is suppressed by performing an average calculation of each phase using the equation (1).
[0071]
[Expression 1]

[0072]
In the calculation of the drive signal switching time (next phase switching time) of the regenerative transistors Tr1 to Tr6, the time between the rise time and the fall time of the phase voltage phase detection signal of the phase where the drive signal is not switched is calculated. Do what you want. Thereby, for example, the timing at which the regeneration transistor Tr1 is switched from the on operation to the off operation and the regeneration transistor Tr3 is switched from the off operation to the on operation is an intermediate point from the fall to the rise of the T-phase voltage phase detection signal.
[0073]
That is, the next phase switching time is obtained by adding the half cycle of the power cycle to the intermediate time between time tn-1 and time tn-4 (2)
Next phase switching time = [{(tn−1) + (tn−4)} / 2] + power supply cycle / 2
... (2)
Can be obtained. Since the drive signals of the regenerative transistors Tr1 to Tr6 are generated based on the power supply cycle thus determined and the next phase switching time (FIG. 8 (5)), the regenerative transistors Tr1 to Tr6 are turned on at the original timing.・ It will turn off.
[0074]
Next, a configuration in which the regenerative signal generation unit 22 shown in FIG. 6 performs a correction operation for voltage imbalance and harmonic distortion based on the detection waveform of the power supply voltage waveform detection unit 21 will be described. FIG. 9 is a block diagram showing a configuration example of the power supply voltage waveform detection unit 21 shown in FIG. 1 as an embodiment of the present invention.
[0075]
In FIG. 9, the power supply voltage waveform detection unit 21 includes a three-phase bridge rectifier circuit including diodes D31 to D36. This three-phase bridge rectifier circuit rectifies the three-phase voltage input from the three-phase AC power supply 2 through the reactors LR, LS, and LT. Between the “+” and “−” outputs of this three-phase bridge rectifier circuit, a resistor voltage divider circuit comprising a series circuit of resistors R4 and R5 is connected, and the divided voltage of the rectified pulsating waveform voltage is the resistor R5. Appears at both ends of. The voltage across the resistor R5 is input to the A / D converter 92 via the amplifier 91. The A / D converter 92 samples the pulsating voltage waveform rectified by the three-phase bridge rectifier circuit, and uses each sampled value (Vref shown in FIG. 1) as a monitoring signal for the regenerative signal generator 22 shown in FIG. The data is output to the MPU 69.
[0076]
In other words, the MPU 69 constantly monitors the power supply voltage waveform from the power supply voltage waveform detection unit 21 to detect power supply voltage imbalance (voltage imbalance, phase difference) and power supply harmonic distortion. The on / off operation timings of the regenerative transistors Tr1 to Tr6 are corrected so that a stable power regeneration operation is possible. The correction operation will be specifically described below with reference to FIGS.
[0077]
FIG. 10 is a time chart for explaining the regenerative operation when an unbalance occurs in the three-phase voltage in the power regeneration converter according to the embodiment of the present invention in which the regenerative operation shown in FIG. 7 is performed.
[0078]
As described with reference to FIG. 8, for example, the MPU 69 determines the ON / OFF operation switching timing between the R-phase upper arm regenerative transistor Tr1 and the S phase upper arm regenerative transistor Tr3 as the fall of the T phase voltage phase phase detection signal. And is set at the midpoint of the rise.
[0079]
In this case, when an imbalance (voltage imbalance, phase difference) occurs in the power supply voltage, there is a difference between the intermediate point defined above and the phase change point where the voltage is maximum or minimum. Will occur. For example, FIG. 10 shows the case where only the R-phase voltage is high, but as shown in FIG. 10 (2), the intermediate point between the falling and rising edges of the T-phase voltage phase-phase detection signal, the R-phase voltage and S There is a time t0 deviation between the phase voltage and the phase change point.
[0080]
Therefore, as shown in FIG. 10 (3), the MPU 69 constantly monitors the switching phase of the voltage maximum value in the power supply voltage waveform from the power supply voltage waveform detection unit 21, and detects the deviation as described above. Is stored, and the change timing of the drive signal applied to the regenerative transistors Tr1 to Tr6 is corrected and output to the comparator 68.
[0081]
As a result, even when an unbalance occurs in the power supply voltage, as shown in FIG. 10 (4), the phase switching timing at which the voltage is maximum or minimum and the on / off operation timing of the regenerative transistors Tr1 to Tr6 Can always be made to coincide with each other, and a regenerative current can be passed through the phase with the highest voltage (FIG. 10 (5)).
[0082]
Next, FIG. 11 is a time for explaining the determination of stopping the regenerative operation when harmonic distortion occurs in the three-phase voltage in the power regeneration converter according to the embodiment of the present invention in which the regenerative operation shown in FIG. 7 is performed. It is a chart.
[0083]
FIG. 11 (1) shows a state in which harmonic distortion occurs in the three-phase voltage. As described above, the MPU 69 can detect the phase with the highest line voltage based on the power supply voltage waveform from the power supply voltage waveform detection unit 21.
[0084]
Therefore, when the voltage of the DC buses 16 and 17 decreases, the MPU 69 monitors the regenerative current detected by the regenerative current detector 19 at the phase where the detected line voltage is the highest, as shown in FIG. . Then, the regenerative current sampling phase for stopping the regenerative operation (marked with * in FIG. 11 (3)) is corrected to the phase where the regenerative current becomes the smallest, and the regenerative stop is determined.
[0085]
As a result, stable regenerative operation stop control can be performed even when there is a power waveform distortion as shown in FIG. Even when there is an imbalance in the three-phase voltage, it is possible not to perform the regeneration stop determination in the low voltage phase as described above, so that stable regeneration control can be performed.
[0086]
Needless to say, the correction operation in the case where the three-phase voltage is unbalanced or in the case where the harmonic distortion is generated can be similarly applied to the conventional voltage phase detection method using the zero-cross point detection of the line voltage.
[0087]
【The invention's effect】
As described above, according to the present invention, when a deviation is detected in the switching timing of the phase voltage, that is, when the three-phase voltage is unbalanced, the regenerative transistor is turned on / off in accordance with the unbalanced state. Since the change timing of the drive signal can be corrected, the power regeneration can be normally performed even when the three-phase voltage is unbalanced.
[0088]
According to the next invention, when the terminal voltage of the smoothing capacitor is lowered, the regenerative operation stop determination is performed using the regenerative current of the phase where the voltage becomes the maximum, so that the harmonic distortion occurs in the power supply voltage. Even in this case, the regenerative operation can be stably stopped.
[0089]
According to the next invention, a three-phase AC power source Phase of Detected by voltage zero cross detection Voltage phase Change timing When Regenerative transistor on / off operation timing and The Can be different. Therefore, the power supply phase can be stably detected without being affected by the spike-like distortion voltage generated due to the on / off operation of the regenerative transistor.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration example of a power regeneration converter to which the present invention is applied.
FIG. 2 is a time chart for explaining start and stop of a regenerative operation in the power regeneration converter shown in FIG.
FIG. 3 is a time chart for explaining a regenerative operation that is generally performed in the power regeneration converter shown in FIG. 1;
4 is a time chart illustrating a regenerative operation when an unbalance occurs in a three-phase voltage in a power regeneration converter in which a general regenerative operation shown in FIG. 3 is performed.
5 is a time chart for explaining the regenerative operation when harmonic distortion occurs in the three-phase voltage in the power regeneration converter in which the general regenerative operation shown in FIG. 3 is performed.
6 is a block diagram showing a configuration example of a phase detection unit and a regenerative signal generation unit shown in FIG. 1 as an embodiment of the present invention.
7 is a time chart illustrating a regenerative operation in a power regeneration converter according to an embodiment of the present invention including the phase detector and the regenerative signal generator shown in FIG.
8 is a time chart for explaining a regeneration signal generation operation of the regeneration signal generation unit shown in FIG.
9 is a block diagram showing a configuration example of a power supply voltage waveform detection unit shown in FIG. 1 as an embodiment of the present invention.
10 is a time chart for explaining a regenerative operation when an unbalance occurs in the three-phase voltage in the power regeneration converter according to the embodiment of the present invention in which the regenerative operation shown in FIG. 7 is performed. FIG.
11 is a time chart for explaining stop determination of regenerative operation when harmonic distortion occurs in the three-phase voltage in the power regenerative converter according to the embodiment of the present invention in which the regenerative operation shown in FIG. 7 is performed. .
[Explanation of symbols]
1 power regeneration converter, 2 three-phase AC power supply, 3 three-phase induction motor (motor), 4 inverter device, 5 reactors (LR, LS, LT), 11 to 13 AC power supply terminal, 14, 15 DC power supply terminal, 16, 17 DC bus, 18 DC voltage detector, 19 regenerative current detector, 20 phase detector, 21 AC voltage waveform detector, 22 regenerative signal generator, C smoothing capacitor, Tr1, Tr2, Tr3, Tr4, Tr5, Tr6 regenerative Transistor, D1 to D6 diode, OI1, OI2, OI3 photocoupler, 66 timer, 67 latch circuit, 68 comparator, 69 microprocessor unit (MPU), D31 to D363 phase bridge rectifier diode, R4, R5 resistor A resistor constituting the voltage dividing circuit, 92 A / D converter.

Claims (3)

Phase detection means arranged between a three-phase AC power supply and a control device for variable speed control of the three-phase induction motor, and a phase detection means for detecting the voltage phase of the three-phase AC power supply, and induction generated when the three-phase induction motor is decelerated Based on the detection signal of the phase detection means, a regenerative transistor for switching the terminal voltage of the smoothing capacitor for accumulating the electromotive force to perform a power regenerative operation on the three-phase AC power supply, and an on / off drive signal for the regenerative transistor In a power regeneration converter comprising regeneration signal generating means,
The regenerative signal generation means monitors the voltage waveform of the three-phase AC power supply, and shifts between the maximum or minimum phase voltage switching timing and the intermediate position between the voltage phase change points detected by the phase detection means. A power regenerative converter that corrects the change timing of an on / off drive signal applied to the regenerative transistor to a timing at which the phase voltage is switched when detected. Phase detection means arranged between a three-phase AC power supply and a control device for variable speed control of the three-phase induction motor, and a phase detection means for detecting the voltage phase of the three-phase AC power supply, and induction generated when the three-phase induction motor is decelerated Based on the detection signal of the phase detection means, a regenerative transistor for switching the terminal voltage of the smoothing capacitor for accumulating the electromotive force to perform a power regenerative operation on the three-phase AC power supply, and an on / off drive signal for the regenerative transistor In a power regeneration converter comprising regeneration signal generating means,
The regenerative signal generation means monitors the voltage waveform of the three-phase AC power supply, detects the phase at which the voltage of the three-phase AC power supply becomes maximum when the terminal voltage of the smoothing capacitor decreases, and A power regeneration converter that corrects the regenerative current sampling phase to a phase that minimizes the regenerative current . The regenerative signal generation means is an intermediate position between voltage phase change points at which the phase detection means detects the voltage phase of the three-phase AC power supply by zero-cross detection of the phase voltage. 3. The power regeneration converter according to claim 1, wherein the power regenerative converter is generated so as to change at a timing at which a line voltage difference of the three-phase AC power supply becomes zero with reference to .

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