JPH04304169A - PWM device and power supply device for power supply - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power PWM device and a power supply device used in inverters, switching regulators, and the like.

0002

2. Description of the Related Art First, an outline of a conventional PWM control type inverter power supply device will be explained.

FIG. 3 is a circuit diagram of a switching section of a conventional inverter power supply, in which 11 is a full-wave rectifier circuit that rectifies the AC voltage from a three-phase AC power supply 12, 13 is a smoothing capacitor, and 14 to 19 are circuits for rectifying the AC voltage from the three-phase AC power supply 12. 1st to 6th switching elements (
20 to 25 are diodes, 26 is a motor driven by three-phase AC voltage, BUP is the base terminal of the first switching element 14, EUP is the emitter terminal of the first switching element 14, and BUN is the second switching element 15. The base terminal, EUN, is the second switching element 15
BVP and EVP are the base terminal and emitter terminal of the third switching element 16, respectively.
BVN and EVN are the base terminal and emitter terminal of the fourth switching element 17, respectively, BWP and EWP are the base terminal and emitter terminal of the fifth switching element 18, respectively, and BWN and EWN are the sixth switching element 19, respectively.
are the base terminal and emitter terminal of.

In the figure, a first switching element 14
and the second switching element 15 are connected in series with each other and in parallel with the smoothing capacitor 13, and the third and fourth switching elements 16 and 17 and the fifth and sixth switching elements 18 and 19 are also connected in series. Similarly, they are connected in series with each other and in parallel with the smoothing capacitor 13. Diodes 20 to 25 are connected in parallel to each switching element 14 to 19, respectively. Also U
, V, and W are power supply lines for supplying three-phase AC power supply voltage to the motor 26, respectively, and the voltage is taken out from the connection point of the corresponding pair of switching elements. That is, the power line U connects the first and second switching elements 1
The power line V is connected to the connection point of the third and fourth switching elements 16 and 17, and the power line W is connected to the connection point of the third and fourth switching elements 16 and 17.
are connected to the connection points of the fifth and sixth switching elements 18 and 19, respectively.

FIG. 4 is a waveform diagram of a motor speed setting signal, where A, B, and C are sine wave signals for setting the motor speed, and T is a triangular wave signal. In the figure, the phase differences between sine wave signals A and B, sine wave signals B and C, and sine wave signals C and A are equal to 120 degrees (hereinafter, these three sine wave signals A, B, C are collectively referred to as motor speed setting signals). Further, the period of the triangular wave signal T is fixed.

Both the motor speed setting signals A, B, and C and the triangular wave signal T are input to a comparator, which will be described later, and a PWM (pulse width modulation) wave signal is output from the comparator. and,
The duty ratio of this PWM wave signal changes depending on the cycle of motor speed setting signals A, B, and C. Then, according to the PWM wave signal, the first to sixth switching elements 1
By controlling 4 to 19, each power line U, V, W
A voltage is generated between them to drive the motor 26.

FIG. 5 shows the first to sixth switching elements 14 to
19 is a circuit diagram of a control system for controlling 19, 27 is a comparator (differential amplifier), 28 and 29 are AND (AND)
30 and 31 are delay circuits consisting of a capacitor C and a resistor R; 32 is a NOT circuit; 33 is a photocoupler consisting of a light emitting diode D and a light receiving transistor Tr;
34, 35, 36 are transistors; 37 is a first PWM circuit consisting of a comparator 27, AND circuits 28, 29, delay circuits 30, 31, and a NOT circuit 32; 38, 39 are first PWM circuits;
Second and third PWM circuits having the same configuration as the WM circuit 37, 4
0 is a photocoupler 33 and transistors 34, 35, 36
The first drive circuits 41 to 45 are second to sixth drive circuits having the same configuration as the first drive circuit 40. In the figure, each PWM circuit 37, 38, 39 is a device that generates a PWM wave signal and prevents a pair of switching elements, such as switching elements 14 and 15, from being turned on at the same time. In the first PWM circuit 37, the signals delayed by the delay circuits 30 and 31 are input to one input terminal of the AND circuits 28 and 29, and the undelayed signal is input to the other input terminal. A NOT circuit 32 is inserted upstream of a signal processing section consisting of one delay circuit 31 and an AND circuit 29. The comparator 27 receives the motor speed setting signal A and the triangular wave signal T,
Outputs a PWM wave signal. The PWM wave signal output from the comparator 27 is input as is to one signal processing section consisting of the delay circuit 30 and the AND circuit 28, and the PWM wave signal output from the comparator 27 is inputted as is to the other signal processing section consisting of the delay circuit 31 and the AND circuit 29.
A signal obtained by inverting the WM wave signal by the knot circuit 32 is input.

The photocoupler 33 of the first drive circuit 40 is for insulation. Also, the transistor 34 is an NPN
The transistor 35 is a PNP type, and when the bases of both transistors 34 and 35 become high (Hi), the NPN type transistor 34 is always turned on, and the PNP type transistor 35 is always turned off. Become. The transistor 36 is for amplifying the output signal of the photocoupler 33, and the voltage amplified by this transistor 36 is applied to the bases of the transistors 34 and 35. And the output is the transistor 34,
35, that is, point E, and sent to BUP, which is the input terminal of the first switching element 14 in FIG. Further, the collector of the transistor 35 is connected to EUP of the first switching element 14. In addition, for the other sine waves B and C, the second and third PWM circuits 38 and 39
Similar operations are performed in the second to sixth drive circuits 41 to 45, and outputs are sent to terminals BUN to EWN of each switching element 15 to 19. Therefore, the PWM wave signal is input to each terminal of the pair of switching elements, as shown in FIGS. 6(a) to 6(f), and the pair of switching elements are not turned on at the same time. Further, line voltages as shown in FIGS. 7(a) to 7(c) are applied to the motor 26 to drive the motor 26.

[0009]

However, each of the PWM circuits 37, 38, and 39 of the prior art described above uses two delay circuits 30, 31, two AND circuits 28, 29, and one NOT circuit. The problem was that the circuit became large.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and aims to provide a power source PWM device and a power source device that have a compact circuit configuration and can prevent short-circuiting of the power source due to simultaneous turning on of switching elements.

[0011]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a PWM means for generating a first PWM signal, and a shifter for delaying the first PWM signal and generating a second PWM signal. register means and the first and second PWs;
means for calculating the AND of the M signals; and the first and second PWMs.
It has a configuration including a calculation means for NOR of signals.

The power supply device of the present invention includes means having the above structure.

[0013]

[Operation] With the above configuration, the present invention has a compact circuit structure, and, for example, output signals of each calculation means are used to control on/off of series-connected switching elements of the switching section of an inverter power supply device as shown in FIG. When used for this purpose, there is an off period between control signals corresponding to the delay time created by the shift register, so the series switching elements do not turn on simultaneously, and a short circuit of the power source does not occur.

[0014]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In FIG. 1, 1 is an AND circuit, 2 is a NOR circuit, 3 is a shift register circuit, 4 is a comparator, 5 is a PWM circuit consisting of an AND circuit 1, a NOR circuit 2, a shift resistor circuit 3, and a comparator 4; 6 is a sine wave signal generating section, and 7 is a triangular wave signal generating section.

The outputs of the sine wave signal generator 6 and the triangular wave signal generator 7 are input to the comparator 4, a PWM wave signal is output from the comparator 4, and one input terminal of the AND circuit 1 is connected to the shift register circuit 3. A PWM wave signal delayed by is inputted to the other input terminal, and a PWM wave signal that is not delayed is inputted to the other input terminal. On the other hand, one input terminal of the NOR circuit 2 has PW delayed by the shift register circuit 3.
An M-wave signal is input, and an undelayed PWM wave signal is input to the other input terminal.

FIGS. 2(a) to 2(d) show the output waveforms of each part of the circuit, where (a) is the output waveform of the PWM wave signal, and (b) is the output waveform of the PWM wave signal delayed by the shift register circuit 3. , (C) are the output waveforms of the AND circuit 1, and (D) are the output waveforms of the NOR circuit 2. Therefore, since there is an off period corresponding to the delay time by the shift register circuit between the outputs (c) and (d), these outputs will not turn on the pair of switching elements (see Figure 3) at the same time. .

As described above, the PWM for power supply according to the embodiment of the present invention
According to the device, it can be easily configured from a comparator, an AND circuit, a NOR circuit, and a shift register, and when the outputs of the AND circuit and NOR circuit are used to control the series-connected switching elements of an inverter power supply, there is no difference between the control signals. Since there is an off period corresponding to the delay time due to the shift register,
There is no simultaneous on state of the series switch elements, and no short circuit of the power supply occurs.

It goes without saying that the power supply PWM device of this embodiment can be used not only for power inverter power supply devices but also for various power supply devices that utilize switching operations.

[0020]

As is clear from the above embodiments, the present invention provides a PWM for power supply that can prevent short-circuiting of the power supply due to simultaneous turning on of power switching elements with a simple circuit configuration.
Equipment and power supplies can be provided.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a power supply PWM device according to an embodiment of the present invention.

[Figure 2] Waveform diagram of the main parts of the device

[Figure 3] Circuit diagram of the switching section of a conventional inverter power supply device

[Figure 4] Waveform diagram of motor speed setting signal

[Figure 5] Circuit diagram of a conventional switching element control system

[Figure 6] Input waveform diagram of conventional switching element

[Figure 7] Voltage waveform diagram supplied to the three-phase motor

[Explanation of symbols]

1 AND (AND) circuit 2 NOR circuit 3 Shift register circuit 4 Comparator 6 Sine wave signal generator 7　Triangular wave signal generation section

Claims (2)

[Claims] 1. PWM means for generating a first PWM signal, shift register means for delaying the first PWM signal and generating a second PWM signal, and logic of the first and second PWM signals. a product calculation means, and the first and second P
PWM for power supply equipped with calculation means for NOR of WM signals
Device. 2. A power supply device comprising the power PWM device according to claim 1.