JPS6031189B2 - transistor inverter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transistor inverter with a simple configuration that allows highly accurate output voltage control.

Conventionally, the output voltage of a transistor inverter has been controlled by 'a) DC input voltage adjustment methods such as adjusting the voltage of a rectifier on the power supply side or using a DC chopper on the DC side, {b} adjusting the phase of the conduction width and using a large-capacity inverter. There are methods in which the inverter circuit itself has a voltage regulating function.

The present invention relates to the above-mentioned method 'al, which includes a switching transistor group for switching energization to a load, an oscillator with a variable oscillation frequency, and a drive signal that sequentially drives the transistor group based on the oscillation frequency of the oscillator. and a monostable multipipulator that forms a pulse train with a constant ON width based on the oscillation frequency, and performs chopper control of the current supplied to the transistor group based on the pulse train, thereby achieving highly accurate output voltage control. It is an object of the present invention to provide a transistor inverter with a simple structure that can be used.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments shown in the drawings, with an electric motor having three-phase stator windings U, V, and W connected as a load.

FIG. 1 is a diagram showing the configuration of a transistor inverter according to the present invention, and FIG. 2 is a diagram showing its time chart.

Figure 3 is a diagram showing the output pulse train of a monostable multipipulator when the oscillation frequency of the oscillator is changed;
The figure is a diagram showing characteristics of FV (frequency-voltage) conversion between the oscillation frequency of the oscillator and the output voltage. Furthermore, Figure 5,
FIG. 6 is a diagram showing an embodiment in which the configuration of the transistor group is changed and the state of energization to the load.

In FIG. 1, 1 is an oscillator whose oscillation frequency can be adjusted freely, 2 is a frequency divider that divides the output signal of the oscillator 1, and 3 is a transistor group 4 based on the output signal of the frequency divider 2.
This is a distributor that forms a drive signal that is sequentially distributed to

That is, the frequency divider 2 and the distributor 3 constitute a drive signal forming section for the transistor group 4.

The transistor group 4 includes switching transistors 5,
6 and 7, which are connected in series to the windings U, V, and W, respectively.

8 is a monostable multipipelator connected to the oscillator 1, which oscillates at the same oscillation frequency as the oscillator 1, and which always forms a pulse train with a constant ON width regardless of frequency changes; Driven by a pulse train,
This is a chopper that chopper-controls the current supplied from the power supply 10 to the load 11 and the transistor group 4.

The time chart of the transistor inverter with the above configuration is as shown in FIG.
The oscillation frequency f of the oscillator 1 is divided into f/5 by the divider 2, and based on this output signal, the divider 3 generates a drive signal for the transistor group 4. fu
, fv, ftv and the drive signals fu, f
v and fw are sequentially distributed to the respective transistors 5, 6, and 7, and the transistor group 4 is in an active state.

On the other hand, since the current supplied to the transistor group 4 is chopper-controlled by the chopper 9 driven by the pulse train P, when combined with the operation of the transistor group 4, the motor windings U, V, W constituting the load 11 Chopper currents such as Pu, Pv, and Pw are applied.

In the above configuration, by operating the oscillator 1 to change the oscillation frequency, the oscillation frequency of the monostable multipipulator 8 changes in the same way, so the inverter output voltage varies depending on the change in the oscillation frequency of the oscillator 1. It is possible to obtain excellent F-V conversion characteristics that change almost linearly in proportion to the amount.

That is, when the oscillator 1 is operated to change the oscillation frequency to f, f/2, and f/4 as shown in FIG.
2, P/4 and the same aircraft, but at this time the pulse train is ON
Since the width is always constant regardless of frequency changes, the pulse train duty ratio (ON width/
- cycle width) is reduced, high-precision F/V conversion is performed based on the three oscillation frequencies of the oscillator 1, and the inverter output voltage is controlled. Since the output frequency signal of the oscillator 1 simultaneously forms the drive signal for the transistor group 4 and the drive signal for the chopper 9, the configuration is extremely simple, and it is especially easy to incorporate and connect to microcomputer equipment that mainly uses digital control. It can be an easy structure.

On the other hand, the configuration of the transistor group 4 can be changed as appropriate depending on the target load. For example, in order to approximate the energization waveform to the load 11 to a sine wave, the configuration of the transistor group 4 is changed as shown in FIG. Each and every one of them.

When configured with three-phase transistors connected in a zero push-pull manner, the active states of the windings of each phase by each transistor and the current waveforms actually chopper-controlled by the chopper 9 are fx and Px shown in FIG. 6, respectively. By operating the oscillator 1, similar excellent F-V conversion characteristics can be obtained.

As explained above, the present invention provides a transistor inverter that can perform highly accurate output voltage control through F-V conversion, has a simple configuration, and is easy to connect to digital control equipment such as a microcomputer. Obtainable.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of a transistor inverter according to the present invention, and FIG. 2 is a diagram showing its time chart. FIG. 3 is a diagram showing the output pulse train of the monostable multipipulator when the oscillation frequency of the oscillator is changed, and FIG. 4 is a diagram showing the conversion characteristics between the oscillation frequency of the oscillator and the inverter output voltage. Further, FIGS. 5 and 6 are diagrams showing an embodiment in which the configuration of the transistor group is changed and the state of energization to the load. 1... Oscillator, 2...
...Frequency divider, 3...Distributor, 4...Transistor group, 8...Monostable multipipulator, 9...Chopper, 11. ·····load. Figure 3 Hair 1 Figure Younger brother 2 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] 1. A drive signal forming section consisting of a switching transistor group for switching energization to a load, an oscillator with a variable oscillation frequency, a frequency divider and a distributor that sequentially drive the transistor group based on the oscillation frequency of the oscillator, and the A transistor inverter comprising a monostable multivibrator that forms a pulse train with a constant ON width based on an oscillation frequency, and chopper-controls power supplied to the transistor group based on the pulse train.