JPS62213590A - Chopper gate control system - Google Patents

Abstract

PURPOSE:To suppress an oscillation phenomenon due to a negative resistance by providing a delay element to detect a voltage when detecting power. CONSTITUTION:The conduction rate of a chopper switch SW is controlled by closing a gate when the integrations of the products of predetermined power obtained as functions of a command torque Tm and a speed Nm for necessary energy in chopping period T, a chopper voltage (power source voltage) Vl'', and chopper current ic become equal. A primary delay element 39 is provided in the chopper voltage detector. Thus, an oscillation phenomenon occurring when a power source filter capacitor 9 is provided can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a gate control method in a chopper control device, and particularly to a gate control method suitable for stabilizing motor drive.

[Background of the invention]

Conventionally, for example, in the chopper gate control method described in the published publication (Japanese Patent Application No. 58-130827), when a power control method is used, the impedance seen from the overhead line side is exhibited negative resistance, so if a power supply filter was present, the negative resistance could cause an oscillation phenomenon, resulting in loss of control.

[Purpose of the invention]

An object of the present invention is to suppress the oscillation phenomenon caused by load resistance, which is a problem of the above power control method, and to provide a stable chopper control method.

[Summary of the invention]

In order to achieve the above object, the present invention focuses on the fact that the quick response of gate control to changes in power supply voltage in a power control method generates negative resistance as seen from the power supply side, and the present invention has been developed to A delay element is provided to suppress the immediate response to power supply voltage fluctuations and to eliminate the resonance phenomenon with the power supply side impedance.

[Embodiments of the invention]

FIG. 1 shows the overall configuration of the present invention, where 1 is a chopper switch SW such as a thyristor, 2 is a flywheel diode D2, 3 is a gate control section, 41 is a motor armature, and 42 is a field winding. , 5 is a smoothing reactor, 6 is a tacho generator TG, 7 is a power supply, 8 is a power filter reactor Lx, 9 is a filter capacitor Cx, and there is a power filter Lt=Ct.

In the configuration shown in FIG. 1, the current flow rate control of the chopper switch Sw is conventionally performed by multiplying the required energy in the chopping period T by the period by the required power obtained as a function of the command torques T and N. and by closing the gate when the integral of the product of the chopper voltage (within the supply voltage Vt) and the chopper current ic equals the required energy.

is under control. Figure 2 is the control block diagram.
31. 32 is a multiplier, 33 is an integrator, 34 is a comparator, 3
5 is a flip-flop, 36 is a chopping period/decision pulse generator, 37 is a gate pulse amplifier, and 38 is a gate pulse transformer.

The operating characteristics of the chopper realized by the circuit shown in Figure 2 are as follows:
As stated in Japanese Patent Application No. 58-130821, it has the characteristics of good output torque characteristics, high responsiveness, and little dependence on power supply voltage.

However, if the power filters Lx and Cn as shown in FIG. 1 are added to the control of the configuration shown in FIG. 2, the voltage of the filter capacitor C1 will cause an oscillation phenomenon, making control impossible.

The reason for this is that the above control has constant power characteristics that are independent of the power supply voltage, and the controlled motor has ideal characteristics that the current and torque do not fluctuate even when the power supply voltage fluctuates.
On the other hand, the impedance seen from the power supply side has negative resistance.

That is, as shown in FIG. 3, when the chopper output power P is controlled to be constant, the power supply current II is as follows with respect to the power supply voltage vt: 1 dew = - (1) V The impedance Z becomes .

A resonant circuit composed of this negative resistance and Lx and Cx of the filter oscillates in a divergent manner, and as a result, chopper control becomes possible.

In order to solve this problem, the present invention adds a first-order delay element 39 to the chopper voltage detection section as shown in FIG. 4, and calculates the chopper output power by the product of its output v1 and IC. This is solved by making the impedance seen from the power supply side include a reactance component instead of a pure negative resistance component.

As shown in the time chart of FIG. 5, the voltage-current characteristics in this case are constant even when V 1 ' changes.

does not change immediately, but exhibits a -order lag response, and by appropriately selecting this lag time constant, it is possible to suppress the oscillation phenomenon on the filter capacitor terminal.

In the above, oscillation is suppressed by adding a delay to the capacitor terminal voltage, that is, the chopper switch supply voltage.
By setting this point to a point obtained by dividing the capacitor terminal voltage at an appropriate ratio, it is possible to make it equivalent to inserting a first-order lag element, and the same effect can be obtained by this method as well.

〔Effect of the invention〕

As described above, according to the present invention, in a chopper that performs constant power or constant current control, the oscillation phenomenon that occurs when a power filter capacitor is present is suppressed, and stable operation is realized.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of the present invention, FIG. 2 is a control circuit block diagram of a conventional example, FIG. 3 is an electrical characteristic diagram thereof, and FIG.
The figure is a control block diagram of the present invention. FIG. 5 is a time response diagram of the present invention. DESCRIPTION OF SYMBOLS 1... Thyristor switch, 2... Flywheel diode, 3... Gate control part, 5... Main circuit reactor, 6... Speed detector, 7... Power supply, 8...
- Power filter reactor, 9... Power filter capacitor, 31.32... Multiplier, 33... Integrator,
34...Comparator, 35...Flip-flop, 37
...Gate pulse amplifier, 38...Gate pulse transformer, 39...Agent: Patent attorney Katsukata Ogawa <1. '
=;' 7Z l Fig. 2 fig. power supply 7ε 詮→

Claims (1)

[Claims] 1. In the chopper gate control method, the required power of the load side to be supplied with power by the chopper device is set in advance, and power equal to the required power is supplied from the chopper side. A chopper gate control method characterized in that a delay element is added to the detection of the supply voltage when the amount of power supplied in one cycle is obtained by integrating the product of instantaneous values of current. 2. The chopper gate control method according to item 1, wherein the delay element for detecting the supply voltage is a first-order delay filter. 3. The chopper gate control method according to item 1, characterized in that the supplied power is obtained using a load current instead of the above-mentioned supplied current. 4. In the chopper gate control method described in item 1, the power supply voltage detection point is a point that includes both the power supply point and the point where the voltage between the filter capacitor terminals is divided. method.