JPS62230386A - Current control system in power converter - Google Patents

Abstract

PURPOSE:To detect currents before the next ignition signal is generated oven when the angle of ignition is shifted to a maximum value by mounting a signal generation circuit reset by an ignition signal and generating at least one pulse signal after a fixed time passes. CONSTITUTION:An ignition control-angle is shifted to a maximum value in order to change the direction of feed of currents, and a current value is reduced suddenly. Since the intervals of ignition pulses outputted from a phase shifter 16 are lengthened at that time, the intervals of the reset of a signal generator 19 are also prolonged. Consequently, the signal generation circuit 19 is not reset within the previously set time, thus generating a pulse signal S2 after a fixed time passes. A CPU 11 detects a current actual value through an analog input circuit 14 every time it receives the pulse S2 through an interrupt controller 13, and starts operation required for changing over the direction of feed of currents immediately after the current value reaches zero.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control method for controlling the current of an inductive load including a motor via a static power converter.

[Conventional technology]

When using a static power converter to control the current value of an inductive load including a motor, the current value is updated every time the static power converter commutates, so the current value is updated in synchronization with the ignition signal. Generally, it is detected and controlled.

[Problem that the invention seeks to solve]

However, in such a method, when changing the current feeding direction or reducing the current value due to the generation of current, it is necessary to shift the ignition control angle to the maximum value, but if this happens, the next time Therefore, (1) Even if the current value becomes zero during a shift, the current feeding direction cannot be changed immediately, as shown in Figure 3 (b). In this case, the dead switching time as shown by T increases.

(2) When recording current values as data for diagnosing the cause of a failure when a failure occurs, the current value is not updated during shifting, so errors may occur as shown by the dotted lines in Figure 6 (B) or Figure 4 (B). The value is recorded.

There were problems such as. In addition, FIG. 6 is an explanatory diagram showing the relationship between the phase shifter output and the current output waveform when changing the feeding direction.
The figure is an explanatory diagram showing the relationship between the phase shifter output and the current output waveform when the current value is decreased due to the occurrence of overcurrent.

Therefore, even when the firing angle is shifted to the maximum value, this invention detects the current value before the next firing signal is generated, thereby reducing wasted time associated with switching the current feeding direction, and correcting the current value. The purpose is to provide a current control method that can record values.

[Means for solving problems]

For a device that uses a static power converter to control the current of an inductive load such as an electric motor in synchronization with a ignition signal of the power converter, it is reset by the ignition signal and generates at least one pulse signal after a certain period of time. A signal generation circuit is provided.

[Effect]

When the ignition control angle is shifted to the maximum value in order to rapidly decrease the current value due to a change in the current feeding direction or the occurrence of an overcurrent, the current value is detected by the signal from the signal generation circuit described above, and the next The current value to be recorded before the ignition signal is generated is updated, and when switching the power feeding direction, the switching can be performed immediately if the current value becomes zero.

[Embodiments of the invention]

FIG. 1 is a block diagram showing an embodiment of the present invention.

The current control device 1 of this embodiment includes a central processing unit (CPU)
11. Memory 121 Interrupt controller 13° Analog input circuit for detecting current value 142 Digital output circuit for outputting firing control angle 151 Phase shifter 16, this phase shifter 1
OR circuit 18 which performs an OR operation of the pulse signals from 6 (12 pulse signals in forward and reverse directions). It is comprised of a delay circuit 17 which delays a signal for a certain period of time, a signal generating circuit 19 which generates at least one pulse signal at certain intervals, and the like.

The waveform diagram of FIG. 2 is also a rare fish, and its operation will be explained below. That is, the firing control angle calculated by the CPU 11 is given to the phase shifter 16 via the digital output circuit 15, and the resulting firing pulse is given to the power converter 6 via the pulse amplifier 5. Anyway, OR circuit 1
8 is input. The output signal is delayed by the delay circuit 17 for a certain period of time (for example, the time until the instantaneous value of the current flowing through the inductive load matches the average value after the ignition pulse is generated), and then is input to the interrupt controller 13. At the same time, the signal generation circuit 19 is reset. The CPU 11 is shown in Figure 2 (
Every time an interrupt signal S- as shown in c) is received, the actual current value is detected as shown in FIG. A proportional-integral adjustment (PI adjustment) calculation is performed, and the ignition control angle is determined from the result and outputted to the digital output circuit 15 again. By repeating the above operations, the current flowing through the power converter 6 is controlled in synchronization with the ignition pulse.

For example, assume that the ignition control angle is shifted to the maximum value in order to change the current feeding direction, and the current value is suddenly decreased. In this case, since the interval between firing pulses output from the phase shifter 16 increases, the signal Q
c) spread widely. For this reason, the signal generating circuit 19 is not reset within a preset time, thereby generating a pulse signal as shown in FIG. 2(d).

Every time the CPU 11 receives this pulse S2 via the interrupt controller 13, it detects the actual current value via the analog input circuit 14, and when the current value becomes zero, it immediately switches the current feeding direction. start an action. As a result, the wasted time for switching is shortened, and current can be detected even during shifting.

〔Effect of the invention〕

According to this invention, even when the ignition control angle is shifted in the direction of narrowing the current in order to reduce the current flowing through the power converter, the current can be detected at a point other than the point synchronized with the ignition pulse. (1) When changing the current feeding direction, the change can be made as soon as the current value becomes zero during the shift, thereby minimizing wasted time.

(2) Even when current values are recorded at regular time intervals in order to diagnose the cause of a failure, the current values are updated during the shift, so correct values can be recorded.

(3) Since overcurrent can be determined during shifting, various advantages are brought about, such as the ability to perform protective operations quickly.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram showing an embodiment of the present invention, Fig. 2 is a waveform diagram of each part to explain its operation, and Fig. 3 shows the relationship between the phase shifter output and current output waveform when changing the feeding direction. The explanatory diagram, FIG. 4, is an explanatory diagram showing the relationship between the phase shifter output and the current output waveform when reducing the current value due to the occurrence of overcurrent. Code explanation 1... Current control device, 2... Rectifier,
3...Transformer, 4...Current transformer, 5...
...Pulse amplifier, 6...Power converter, 7
...Inductive load (motor), 11...
Arithmetic control unit (CPU), 12...Memory, 1
3... Interrupt controller, 14... Analog input circuit, 15... Digital output circuit, 16... Phase shifter, 17... Delay circuit, 18...OR circuit, 19...signal generation circuit.

Claims (1)

[Claims] In a current control method in which the current value of an inductive load driven via a static power converter is detected in synchronization with an ignition signal, and control is performed based on the detected current value, the following points are provided: A signal generation circuit is provided that generates at least one pulse signal every time a predetermined time elapses after the arc signal is output, and when the generation interval of the ignition signal becomes large, the pulse signal from the signal generation circuit is A current control method in a power converter characterized by detecting and controlling a current value based on the current value.