JPS59175384A - Firing method of regenerative rectifier circuit - Google Patents

Abstract

PURPOSE:To always obtain stable commutation by monitoring the phases of the highest and lowest potential phases at the regenerative operation time, and driving the base of a self-extinguishing element of the phase corresponding to the discriminated phase signal on the basis of the signal. CONSTITUTION:Transistor element groups T1-T6 of a regenerative rectifier circuit 1 are nonconductive at the power drive time of a load motor. A DC voltage rectified by the diode element groups D1-D6 of the rectifier circuit 1 is PWM- controlled by a power inverter 2 to obtain power of similar sinusoidal wave. The prescribed base drive signal is obtained by a base drive circuit 6 on the basis of the phase discrimination signal of the highest potential led from the maximum- minimum leading circuit 5 and the phase discrimination signal of the lowest potential, and the groups T1-T6 of the rectifier circuit 1 are base driven by a drive signal which is temporarily amplified by a pulse amplifier 7 from the signal.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ignition method when a self-extinguishing element is connected in parallel to a diode of a diode rectifier as a rectifier circuit for power regeneration, and particularly relates to an ignition method when a self-extinguishing element is connected in parallel to a diode of a diode rectifier. It is an object of the present invention to provide a method for starting a rectifier circuit for power regeneration, which enables stable commutation operation regardless of the situation.

The M inverter is preferably used as a variable frequency power supply for electric motors, but this 1% (a diode rectifier without control capability is used as the inverter's rectifier, but when performing rapid deceleration etc. with such an inverter, As is well known, diode rectifiers cannot perform power regeneration, so a separately excited inverter 3 dedicated to power regeneration is connected to the inverter 4 as shown in Figure 1, and a predetermined 2-way regenerative operation is performed. In Fig. 1, the inverter includes a diode rectifier 1 in which diode D6 is bridge-connected, and thyristor elements Su-8w and 5x-
8z is connected in a pure bridge, and each thyristor element is connected in anti-parallel to feedback diodes Du-Dw and Dx-Dz 1 to form an inverse conversion section 2, and a DC reactor DCL1 of a DC intermediate circuit. Furthermore, the separately excited inverter 3 is a thyristor S! ~ 86W pure spring connection, transformer TF" and glue handle D for suppressing circulating transient current
In particular, the transformer TF uses an isolation transformer for the purpose of preventing circulating current flowing through each diode of the diode rectifier 1 and each thyristor of the separately excited inverter B, and further includes a separately excited inverter B. In order to perform the specified 0N-OFF operation, each of the cyrisk elements 6 requires a required commutation margin angle, so the output voltage of the separately excited inverter is inevitably lower than the T-wave rectification value of the diode rectifier. Therefore, it is inserted for the purpose of stepping up. In such a power regeneration method using a separately excited inverter, if the commercial power supply voltage waveform is distorted, commutation failure is likely to occur due to insufficient commutation margin angle, and furthermore, as mentioned above, the output This method requires an insulating transformer TF and a current suppressing reactor DCL in order to step up the voltage and prevent circulating current, which poses problems such as being uneconomical. For such a regeneration method of a separately excited inverter, for example, each diode element group D of the diode rectifier 1 of the m inverter
A conceivable method is to connect self-extinguishing elements such as transistors in antiparallel to terminals 1 to D6, and regenerate regenerated power from the load side to the commercial frequency power supply bus line through these self-extinguishing elements. This method is shown in Fig. 6, which is an example in which a self-extinguishing element and a transistor element group T1 to T3 are used. Since an isolation transformer and a reactor for suppressing circulating current are not required, the circuit configuration is simplified and an economical system can be realized.
In the commercial line shown in the figure, the transistor T2 in Figure 3 conducts during the V-phase period, which has the highest potential in the source voltage waveform, and for some reason during this V-phase period, the power supply voltage waveform changes as shown in Figure 2. When the W-phase potential becomes higher than the V-phase potential due to distortion, the W-phase diode D3 → the V-phase transistor T!, as shown by the broken line in FIG. Current flows through the path, causing a short circuit on the power supply side. This short circuit current is between W phase and V phase.
It is determined by six quantities: the phase difference voltage, the power supply impedance, and the distortion period of the power supply voltage waveform shown in Figure 2.
The current value of the DC intermediate circuit of the inverter is also added, resulting in a very thick fault current. Therefore, existing power transistor elements have an overcurrent withstand value of 1f that is sufficient to withstand a large fault current, and the transistor element group is thermally destroyed and cannot continue to operate.

The present invention was invented in view of this point, and in particular, during regenerative operation, the self-extinguishing element at the highest potential among the elements to which the commercial frequency power supply voltage is applied, and the self-extinguishing element at the lowest potential The main feature is that stable commutation operation is always possible by determining the ignition method in which the self-extinguishing element in the circuit is always conductive. Explain in detail.

In the embodiment shown in Fig. 4, the main circuit configuration of the zone inverter is exactly the same as that of the conventional device, and on the wood flow side, it is used as a means for introducing the ignition signal of the element group of the regenerative rectifier circuit that operates especially during regenerative operation. , isolation transformer T1 and diode element group D7~
A first rectifier circuit 4 each comprising a rectifier made of D12 and a resistor provided between the DC output terminals of this rectifier.
1 and I!, which has exactly the same configuration as this circuit. 2 rectifier circuit 42
Then, a commercial frequency power source is generated based on the DC output signal that is guided through the stiff rectifier circuit! The maximum value-minimum value groove for deriving the phase with the highest potential and the phase with the lowest potential of the circuit 5 and the transistor element group T of the regenerative rectifier circuit 1 based on the signal derived from this circuit. , -T6, and a pulse amplification circuit 7 that once amplifies the base drive signal constitute a base drive signal generation circuit.

The operation of the nut flow side configured as described above will be described with reference to the time chart shown in FIG. ~T6 is in a non-conducting state, and the inverse converter 2 performs a predetermined PRM control on the DC voltage rectified by the diode element groups D1 to D6 of the circuit 1 to generate a predetermined number of pulses every half cycle of the AC output voltage. The required power of the approximate sine wave that generates the voltage is obtained, and the load motor is continuously operated using the power of the approximate sine wave. When driving in this direction (-), if you rapidly decelerate and drive in reverse, or even more rapidly decelerate and stop,
As is well known, by extinguishing the thyristor element group 5u-8z of the inverse converter 2 and conducting the transistor element group T, -T6 of the regenerative rectifier circuit 1, the regenerative power from the load motor is Although regeneration occurs on the commercial frequency power supply bus through the path of the feedback diode group Du-Dz of the inverse converter 2 and the transistor element groups T1 to T6 of the regenerative rectifier circuit 1, during such regenerative operation, in the wooden embodiment, First, the base drive circuit 6 generates a required pace drive signal based on two signals, the phase discrimination signal at the highest potential and the phase discrimination signal at the lowest potential, which are guided by the maximum value-minimum value derivation circuit 5. This signal is once amplified by the pulse amplification circuit 7, and the drive signal is used to drive the transistor element group T of the regenerative rectifier circuit 1.
Base drive 1 to T6.

The waveform diagram in Figure 5 shows a time chart during such pace drive, where the 5th position shows the commercial frequency power supply voltage waveform, and similarly Figure 5 (l is an example of a rectifier for regeneration). Reverse voltage waveform applied to transistor T2 of circuit 1 (this is also the forward voltage waveform of diode D2)
In FIG. 5, q indicates the pace drive signal of the J-phase transistor T1, FIG. 5 indicates the W-phase pace drive signal, and the fifth outlet indicates the V-phase pace drive signal. Therefore, during the T1 period when the potential of the U phase is the highest, the transistor T1 of the regenerative rectifier circuit 1 is conductive, and the period T is also maintained.

Then, the V-phase transistor T2 becomes conductive.

During such pace drive, during the period when the ■ phase is at the highest potential and correspondingly the V phase transistor T2 is conductive, as shown in FIG. 5(4), time 1. If the power supply voltage waveform becomes distorted and suddenly drops to zero potential for some reason, the W-phase potential will be higher than the V-phase potential, so based on this condition, the maximum value-minimum value derivation circuit 5 At time t1, an ON pace drive signal is applied to the W-phase transistor T3 to make it conductive, and a reverse pace drive signal is applied to the ■-phase transistor T2 to immediately extinguish it. In addition, during this period, the ON pace drive signal given to the element with an open phase on the negative side continues as it is, and the regenerated power is regenerated on the power supply side through the path of the W-phase transistor T and the open-phase transistor T4. That will happen. This operation continues until time t2 when the power supply voltage waveform returns to normal, and the power supply short-circuit accident between v and W that occurs because the V-phase transistor T is in conduction, as seen in conventional devices, is prevented. It can be prevented. Now, at time t1 point, V
When the power supply voltage of the phase is normal, a pace drive signal for ON is given to the transistor T2 of the phase ■ based on the V phase discrimination signal given from the maximum value-minimum value derivation circuit 5, and the transistor T of the W phase is turned on. A pace drive signal for OFF is applied to the load, and the regenerated power from the load is regenerated on the power supply side through the path of the V-phase transistor T2 and the open-phase transistor T4. At time t3, the potential of the W phase becomes higher than the potential of the V phase, so regenerative power is regenerated through the W phase at the highest potential and the open phase at the lowest potential.

As described above, in the present invention, the phase with the highest potential and the phase with the lowest potential in the commercial frequency power supply voltage are monitored during a predetermined regenerative operation, and the corresponding phase is monitored based on the determined phase signal. Since the self-arc-extinguishing element is base-driven, it has a heel-to-heel effect as shown below.

■ Even if power supply voltage distortion or phase loss occurs on the commercial frequency power supply bus side during roundworm operation, each self-extinguishing element for the highest potential phase and lowest potential phase will always respond to the commercial frequency power supply voltage. Since the base drive is set to 5, stable regenerative operation can be performed throughout the entire operating range.

■ The elements that operate during regenerative operation in the regenerative rectifier circuit are self-extinguishing elements such as transistors and gate turn-off thyristors, so the circuit configuration in terms of commutation can be simplified compared to reverse blocking thyristors.

(2) Since it is not necessary to provide an isolation transformer and a circulating current suppressing reactor as seen in separately excited inverters, a very economical inverter device can be realized based on the effect of the above-mentioned zero term.

[Brief explanation of drawings]

Figure 81 is a specific circuit configuration diagram of the inverter showing the conventional regeneration method when using a separately excited inverter.
The figure is a power supply voltage waveform diagram used to explain the regeneration operation of a conventional device when self-extinguishing elements are connected in antiparallel to the diode rectifier of an inverter. A circuit diagram showing a specific example of a conventional regenerative rectifier circuit in which a self-extinguishing element is connected in anti-parallel to a diode rectifier of a PIvM inverter to be used. FIG. Specific circuit configuration diagram,
FIG. 5 is a time chart diagram illustrating the operation during regeneration. 1 is a regenerative rectifier circuit, 2 is an inverse converter, 4. -42 is the first
and a second rectifier circuit, 5 a maximum value-minimum value derivation circuit, 6
is a pace drive circuit, and 7 is a pulse amplification circuit. patent applicant

Claims (1)

[Claims] A self-arc extinguishing element is connected in antiparallel to each diode of the diode rectifier, and during power running, the DC power rectified by the diode rectifier is supplied to the reciprocating converter, and during regenerative operation, the DC power is supplied to the inverse converter through the self-arc extinguishing element group. This is a regenerative rectifier circuit that regenerates regenerative power guided from a group of feedback diodes on the commercial frequency power supply bus side, and controls the self-arc-extinguishing element group at 0N-OFI during regenerative operation. In the device, the phase having the highest potential and the phase having the lowest potential in the commercial frequency power supply voltage are respectively determined, and the half phase of the regenerative rectifier circuit corresponding to these phase discrimination signals is determined. A method for igniting a regenerative rectifier circuit, characterized in that a self-extinguishing element is made conductive.