JPS61244273A - Control power source - Google Patents

Abstract

PURPOSE:To obtain an inexpensive and economic control power source by using a photocoupler to detect an output voltage, and forming the function of fourquadrant calculations of an operational amplifier. CONSTITUTION:An AC power source 1 is converted by a rectifier 2 to a DC, smoothed by a condenser 3, and supplied to a load 4. A switch element 5 is connected in parallel with a rectifier 2A, and an energy from a load side is regenerated to a power source 1 side. Further, the R-phase, S-phase current reference I*R, I*S are compared by current controllers 13A, 13B with current detection signals IR, IS from current detectors 7A, 7B of the phases, and controlled to a target voltage VSR while controlling the current with switch elements 5 to 100% of power factor. In this case, current reference generators 24A, 24B and a voltage controller 23 are provided, a photocoupler for detecting the output voltage Vc is provided in the controller 23, a triangular wave signal VTR is compared with an error signal, and a pulse-width-modulated pulselike switching signal VSW is output to the generators 24A, 24B.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a power supply device capable of pulse width modulation control, and particularly includes a current reference generation circuit that controls input current so as to reduce harmonic current. This invention relates to a controlled power supply device.

[Technical background of the invention and its problems]

FIG. 8 shows a general configuration of a power supply device having a large-capacity capacitor in the main circuit.

The alternating current supplied from the power supply l is rectified by a rectifier circuit 2C and converted into direct current. The capacitor 3 is for smoothing the DC voltage.

Input current of such a circuit1. ．． is shown in Figure 9(b),
The current Ias has a waveform as shown in (C). In the figure, (b) shows the case where the load is small, (C) shows the case where the load is large, and (,) shows the case where the capacitor 3 is not provided for comparison.

In this way, a capacitor input type power supply device contains very large harmonic components, which adversely affects the power supply side. To prevent this, human power ° current 1. ．． A control power source has been developed in which the power factor is 1 with a current close to a sine wave as shown in FIG. 9(d). FIG. 10 shows the conventional configuration of the device.

This device has few low-order harmonics due to the switching operation of the switching element 5, which is inserted at the input side of the power supply and connected in parallel to the accelerator 6 and the two rectifying elements, and the power factor is close to a sine wave with a power factor of 1 (Fig. 9). Input current 1 as shown in (d). . It can be done.

The load 4 is, for example, in the case of an inverter, an induction motor via a group of switches that convert direct current to alternating current, and in the case of Leonard, a direct current motor via switching elements such as transistors.

It is possible to regenerate this energy from the load side to the power source side.

The load voltage VC is detected as a voltage signal V8 by the voltage detection circuit 8, and the voltage reference signal Vs is detected by the voltage control circuit 10.
It is compared with m and is amplified. On the other hand, the power supply voltage synchronization circuit 11
A sine wave signal axis and EG synchronized with the B-phase and S-phase power supply voltages are output from the 12 multipliers.

12B is multiplied by the output "RR" of the voltage control circuit 10 to generate current reference signals of 8 phases and 8 phases.

The current references I- and I- of the B-phase and S-phase are generated in synchronization with the phase voltage of the B-phase and S-phase, respectively, and the input current 11. is generated so that the power factor becomes 1. is controlled. That is, each phase's reef current reference I- and knee are current control circuits 13A,
13B compares and amplifies the current detection signals detected by the current detection circuits 7A and 7B of each phase, and generates voltage control signals v1 and v8 of the phase and S phases, which control the switching of each switching element 5. Power factor: 100%
If the current control is performed, the target voltage V, ”C'JIE
Pressure control is performed.

However, all conventional devices require multipliers and voltage sensing circuits to generate a synchronized sinusoidal current reference, and the multipliers in particular require four-quadrant operations and are expensive. In addition, the voltage detection circuit requires a chopper circuit and an isolation transformer to isolate the voltage of the main circuit and convert it into a voltage that can be used by the control circuit, making it expensive as well. This was a hindrance to its realization.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned problems, and its purpose is to provide a power supply device in which the input current is controlled in a sinusoidal manner by PWM control to reduce harmonic components and control the power factor to 100%. , improved current reference generation, and voltage detection configurations and made them inexpensive (
The objective is to realize and provide an economical control power source.

[Summary of the invention]

In order to achieve the above object, the present invention provides a device equipped with a power converter to which an AC voltage is input, a smoothing capacitor is provided on the DC side, and converts between AC and DC using PWM control.
A voltage detection circuit includes a photocoupler that outputs a voltage detection signal proportional to the output voltage within a predetermined range through which an input current flows according to the output voltage, and a voltage detection circuit that compares the voltage reference signal with the voltage detection signal and responds to the voltage deviation. voltage control means for outputting an error signal in synchronization with the AC voltage; comparison means for comparing the error signal and the triangular wave signal and outputting an on/off command with a ratio according to the error signal; This is an economical control power supply device that is equipped with a current reference generation means that outputs a current reference signal according to the error signal based on the on/off command 1, and that these functions are realized at low cost using common electronic components.

[Embodiments of the invention]

A configuration diagram of an embodiment of the control power supply of the present invention is shown in FIG.
show.

Characteristic parts of the present invention reside in the '1st flow reference generation sections 24A and 24B and the voltage control circuit, and the other components are the same as those of the conventional system and are given the same reference numerals. Note that 17 is a triangular wave generation circuit attached to the voltage control section.

The pressure control unit compares the magnetic pressure reference V□ and the output voltage vc of the control power supply, compares the deviation signal with the triangular wave signal v1, and generates a pulsed switching signal VS+W whose pulse width is modulated according to the difference. Output current reference generation means, 24
At B, a sine wave synchronization signal ex"a outputted from the power supply voltage synchronization circuit 11 and the switching signal v8W12 output a "flux reference signal R+ ka" which is proportional to the product of the deviation signal and the synchronization signal. , thereafter, current control with a power factor of 100% is performed as in the conventional case.

Voltage control unit 23, which is a feature of the present invention. FIG. 2 shows a concrete example of the m-flow standard generation section 24B. Although only the current reference generation section 24A is shown, the current reference generation section 24B is also configured with a similar circuit.

The voltage control unit n includes a voltage detection circuit 5. which detects a signal V8m corresponding to the output magnetic pressure VC. A proportional-integral voltage control circuit 10 compares and amplifies the voltage reference V, - and the signal van, and compares the output signal EIIIL with the triangular wave signal VTR to obtain the signal B.
It is composed of a comparator 16 that outputs on/off commands V and W with a time width corresponding to the time range.

The current reference generation unit 24A includes 21 inverting amplifiers that reverse the polarity of the synchronizing signal am, and a summing amplifier 18A that receives the synchronizing signal em or -eB and has low switching.
, consists of 19 and 20 switches f, which are turned on and off by an on-off command v8W, and 22 phase compensation amplifiers, which compensate for phase delays.

The voltage detection circuit 5 uses a photocoupler 25g to control the current of the light emitting diode, and as shown in the input/output characteristics of FIG.
The configuration is such that an output voltage Vl1m proportional to C is obtained.

This device is a three-phase circuit, and by controlling the R and 8 phase currents, the T phase current is inevitably determined. The T-phase voltage control signal 'IT' is output from the combining circuit 1442 to V- and V-.
It is generated by composing.

Each voltage control signal N'R'' * vB'' g v,'' (analog signal) is a PWM circuit (pulse width modulation circuit) 15
Person, 15B.

15c From l2, on/off command (digital signal)
i2 converted.

The switching element 5 is controlled by the above on-off command so that the load side voltage VC has a value corresponding to the voltage reference signal V1m'', and the input current is close to a sine wave and the overall power factor is 1. controlled.

Hereinafter, the operation of the circuit shown in FIG. 2 will be explained in detail with respect to three modes of the output voltage Bam of the voltage control circuit 10 using FIGS. 4 to 6.

(1) When Eiii is zero (HILR=0) The triangular wave signal vTIL is generated symmetrically between positive and negative, and this is compared with the zero voltage, so in this case, the on/off command Vff output from the comparator 16 is As shown in Figure 4, the generation times T* * Tl of the ON command °1" and the OFF command "0" are equal. With this ON command "1'", only 20 switches are closed, and with the OFF command @0'" Only 19 switches are closed. Therefore, the current 11sll input to the 18 summing amplifiers flows in proportion to the synchronizing signal "Be-e&' as shown in the figure, but the positive and negative are symmetrical and the average of both becomes zero. Therefore, the amplifier' The output signal of the amplifier 18A becomes zero and the phase compensation amplifier 22
The human output signal, that is, the current reference signal generator, also becomes zero. Note that the frequency of the triangular wave signal v1□ is set sufficiently high compared to the power supply frequency, and the ripple value of the current reference signal can be almost ignored due to the filter characteristics of the 18 amplifiers.

(2) When ERR is negative (ERR<O,) In this case, the on/off command VaW output from the comparator 16 is for a time T of 11'' as shown in FIG.

Is it shorter than the time T1 of 1o@? The closing time for 19 switches is longer than the closing time for 20 switches.

Therefore, the input current t, , I! The average value of switch 19
Current flowing due to human closed circuit! , is more dominant, and the output of the amplifier 18A, +/, has a waveform proportional to the negative phase signal (-en) of the synchronizing signal eB, as in the fifth factor.

However, filter characteristic 1 for ripple suppression; synchronization signal e
8, a phase delay of θ occurs. Phase compensation amplifier 22A
compensates for this delayed phase θ as an advanced phase, and its output I- becomes a signal that is in phase with the synchronizing signal e1 and proportional to the signal "1B".

(3) When ER, is positive (1iiIB > 0) In this case, the on/off command v8 which is the output of the comparator 16
As shown in FIG. 6, w is a time T when it is "1" and a time T when it is "O".

Therefore, the output IIL of the 22 phase compensation amplifiers is -2
), the value is proportional to the signal ERR with the opposite phase of the synchronizing signal eB.

As explained above, the output signal of the phase compensation amplifier 22A, that is, the current reference signal In, becomes a signal proportional to the product of the synchronization signal eB and the output signal ERR of the voltage control amplifier 10. Furthermore, although only the R-phase current reference signal 8 has been explained in FIG. 2, the S-phase current reference signal 8 can also be generated in the same manner.

Note that the current reference generation section Saeto can be operated with one switch that is closed by the on/off command VIW, as shown in the circuit diagram shown in FIG.
By setting the resistance value of the input resistor 1 of A to 1/2 of 18, when the 20 switches are closed, the inverse phase value input from the output signal of the 21 inverting amplifiers is twice A similar effect can be obtained by inputting a positive phase value and isometrically inverting the input polarity.

[Effects of the Invention] According to the present invention, a photocoupler is used to detect the output voltage in a power supply device that controls the input current in a sinusoidal manner using PWM control to reduce harmonic components and control the power factor to 1004. In addition, the functions of conventional expensive multipliers capable of four-quadrant operations can be realized with common inexpensive electronic components such as operational amplifiers, and an economical control power supply device can be provided.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the controlled power supply device according to the invention, FIG. 2 is a detailed circuit diagram of the voltage control section and current reference generation sections 24A and 24B in FIG. 1, and FIG. An input/output characteristic diagram of the magnetic pressure detection circuit 5, FIGS. 4 to 6 are signal waveform diagrams for explaining the circuit of FIGS. W&2, FIG. The figure is a general configuration diagram of a capacitor input type power supply device, and Figure 9 is a voltage/current waveform diagram to explain the problem of harmonic generation in the circuit of Figure 8.
FIG. 10 is a configuration diagram of a conventional controlled power supply device designed to suppress harmonic components. l...Input power supply 2...2 rectifier circuits...
- Rectifying element 3... Capacitor 4... Load
5... Switching element 6... Reactor 7 people, 7B... Power current detector 8.25...
・Voltage detector 25B...Photocoupler 9...
Reference voltage generation circuit 10... Voltage control circuit 11...
Power supply voltage synchronization circuit 12 people, 12B...multiplier 13 people, 13B...current control circuit 14...composition circuit 1
5A, 15B, 15c...Pulse width modulation circuit 16...Comparison ratio 17...Triangular wave generation circuit 18 people...Summing amplifier 19 people, 20 people...
21 switches...Inverting amplifier 22A...Phase compensation amplifier n...Voltage control unit 8 people...Current reference generation unit (7317) Agent Patent attorney Nori Chikanori
Yu (and 1 other person) Figure 1 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10

Claims (1)

[Claims] AC voltage is input and there is a smoothing capacitor on the DC side.
In a device equipped with a power converter that converts between alternating current and direct current using M control, voltage detection is equipped with a photocoupler that allows an input current to flow according to the output voltage and outputs a voltage detection signal proportional to the output voltage within a predetermined range. a circuit, a voltage control means for comparing the voltage reference signal and the voltage detection signal and outputting an error signal according to the voltage deviation; and comparing the error signal and the triangular wave signal and turning on a ratio according to the error signal; A control power supply characterized by comprising a comparison means for outputting an off command, and a current reference generation means for outputting a current reference signal according to the error signal based on a synchronization signal synchronized with the alternating current voltage and the on/off command. Device.