KR20010010732A - Apparatus for control the voltage of inverter driving system - Google Patents

Abstract

PURPOSE: An automatic voltage switching apparatus of an inverter driving system is provided to stably drive an inverter driving system regardless of a level of an input voltage by automatically switching a voltage rectifier circuit of an inverter system according to a level of an input voltage. CONSTITUTION: A voltage rectifier(40) rectifies and smooths an input alternating current power supply. An inverter(20) converts a direct current voltage outputted from the voltage rectifier(40) into an alternating current voltage having predetermined amplitude and frequency. An AC variable speed motor(21) receives the alternating current voltage from the inverter(20) and drives a load. A location detector(23) outputs a rotating pulse according to a location of a rotor of the AC variable speed motor(21). A voltage sensor(50) senses an amplitude of a direct current voltage smoothed by the voltage rectifier(40). A circuit switching section(60) switches a voltage circuit of the voltage rectifier(40) to output a regular direct current voltage based on a voltage information sensed in the voltage sensor(50).

Description

Apparatus for control the voltage of inverter driving system

The present invention relates to a voltage automatic switching device of the inverter drive system, and more particularly to a voltage automatic switching device of the inverter drive system capable of stably driving the inverter drive system regardless of the level of the input voltage.

In recent years, countries around the world are tightening energy regulations to reduce energy consumption. Inverter technology is one of the most effective ways to cope with energy regulations in each country.

An inverter is a power converter capable of controlling the magnitude and frequency of voltage or current applied to the motor in order to control the speed of the motor as desired. When the inverter is applied to large appliances such as washing machines or refrigerators and air conditioners, energy and noise can be reduced, and basic functions of the product can be improved, and additional functions such as rapid heating and cooling, improved comfort, and freshness are provided. Can be implemented.

FIG. 1 is a block diagram of an inverter driving system applied to such a large home appliance, and voltage rectifying units 10A and 10B are configured differently as shown in (a) and (b) according to the rating of a commercial AC voltage input thereto. do.

As shown in the figure, the inverter drive system uses the voltage rectifiers 10A and 10B for rectifying and smoothing the commercial AC voltages, and the DC voltages output from the voltage rectifiers 10A and 10B to any amplitude and any frequency. Inverter unit 20 for converting into alternating voltage having a variable speed, variable speed motor (for example, brushless motor 21) for driving a load by receiving the alternating voltage converted from inverter unit 20, and variable speed motor 21 The switching element of the inverter unit 20 is turned on by the position detection unit 23 which outputs the rotation pulse according to the electronic position, and the duty ratio set based on the rotation pulse output from the position detection unit 23 and the operation information of the load. The inverter driving circuit unit 30 controls the operation of the variable speed motor 21.

On the other hand, when the input power source 1 is AC 220V, the voltage rectifying part is comprised as shown to Fig.1 (a). When AC 220V is input, it is rectified by the rectifying circuit 11 consisting of four rectifying elements (not shown), smoothed by a smoothing circuit 12A consisting of one capacitor C1, and outputs approximately DC 300V. The three-phase power is supplied to the variable speed motor 21 by conducting the switching element of the inverter part 20 by the switching signal output from the inverter drive circuit part 30.

In addition, when the input power supply 2 is AC110V, the double voltage rectification part is comprised as shown in FIG.1 (b). When AC 110V is input, it is rectified by the rectifying circuit 11 consisting of four rectifying elements, smoothed by the smoothing circuit 12B consisting of two capacitors C2 and C3, and outputs approximately DC 300V. The three-phase power is supplied to the variable speed motor 21 by conducting the switching element of the inverter part 21 by the switching signal output from 30. FIG.

However, in the conventional inverter drive system, the voltage rectifier circuit is configured in advance to supply the appropriate DC voltage to the motor according to the level of the commercial AC voltage input, and the inverter drives the AC 220V rating in the AC 110V supply area inadvertently by the user. In case of using the system, the high voltage of DC 600V is supplied to the motor by the preset voltage rectifier and the motor is burned out, or when the inverter driving system with the rating of AC 110V is used in the AC 220V supply area, DC 150V was supplied to the motor, there was a problem that the inverter drive system does not operate due to the lack of voltage. In addition, when the supply voltage does not match the rating of the inverter drive system, there was a inconvenience to use a separate boost or step-down device.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and its object is to automatically switch the voltage rectifying circuit of the inverter driving system in accordance with the level of the input voltage to stably drive the inverter driving system regardless of the level of the input voltage. To provide a voltage automatic switching device of the inverter drive system.

1 (A), (B) is a block diagram of a conventional inverter drive system,

2 is a block diagram of a voltage automatic switching device of an inverter drive system according to the present invention;

3 and 4 is an operating state diagram of the voltage automatic switching device of the inverter drive system according to the present invention.

* Description of the symbols for the main parts of the drawings *

20: inverter portion 30: inverter drive circuit portion

40: voltage rectifier 41: rectifier circuit

42: smoothing circuit 50: voltage sensing unit

60: circuit switching part

In order to achieve the above technical problem, a configuration of the present invention includes: a rectifying voltage rectifying unit for rectifying and smoothing a commercial AC voltage, and converting a DC voltage output from the voltage rectifying unit into an AC voltage having an arbitrary amplitude and an arbitrary frequency. In the voltage automatic switching device of the inverter drive system having an inverter unit and a motor for driving the AC voltage converted by the inverter unit, the voltage sensing unit to detect the level of the applied commercial AC voltage Based on the voltage detection unit for dividing the output DC voltage, and the level of the commercial AC voltage applied based on the voltage value divided by the voltage detection unit is judged to be lower than the current level of the commercial AC voltage applied commercial AC voltage applied A system control unit for outputting a control signal for backing the DC voltage according to If a call is characterized in that a circuit comprising a switching circuit for switching the voltage from the voltage rectifying part so that the output is a suitable back-pressure direct-current voltage driving the motor.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 is a block of the voltage automatic switching device of the inverter drive system according to the present invention. As shown in FIG. 2, the power stage 3, which is a commercial AC power source, the voltage rectifier 40 for rectifying and smoothing the commercial AC voltage input through the power stage 3, and the voltage rectifier 40 are smoothed. DC voltage rated to stably drive the inverter drive system regardless of the level of the input voltage based on the voltage detection unit 50 for detecting the magnitude of the DC voltage and the voltage information detected by the voltage detection unit 50 The circuit switching unit 60 is configured to switch the circuit of the voltage rectifying unit 40 to output the voltage.

In addition, the inverter unit 20 converts the DC voltage output from the voltage rectifying unit 40 into an AC voltage having an arbitrary amplitude and an arbitrary frequency, and receives an AC voltage converted from the inverter unit 20 to drive a load. The variable speed motor 21, the position detecting unit 23 for outputting a rotation pulse according to the rotor position of the variable speed motor 21, and the rotation pulse output from the position detecting unit 23 and the operation information of the load. The inverter driving circuit section 30 is configured to conduct the switching elements Q1 to Q6 of the inverter section 20 to control the operation of the variable speed motor 21 by the duty ratio. And reference numeral D11-D16 is a reverse protection diode.

Among the above-described components, the voltage rectifier 40 is for rectifying and smoothing a commercial AC voltage of AC 110V or AC 220V input from the power supply stage 3 to output DC 300V suitable for driving a motor. It consists of a rectifier circuit (for example, bridge rectifier; 41) connected to the power supply terminal (3) so as to allow full-wave rectification of commercial AC voltage, and an AC component (pulse) included in the full-wave rectified DC voltage. It consists of a smoothing circuit 42 connected in parallel to the output side c, d of the rectifier circuit 41 so that removal (smoothing) may be possible.

In addition, the smoothing circuit 42 is composed of two capacitors C4 and C5 connected in series, and even when AC 110V or 220V is input, the two capacitors C4 and C5 can output approximately DC 300V to the inverter unit 20. And a circuit switching unit 60 connected between the rectifier circuit 41 and one input terminal (b) to switch the circuit.

In addition, when AC 110V is input, the circuit switching unit 60 electrically connects between two capacitors C4 and C5 and one input terminal b of the rectifier 41 to charge the two capacitors C4 and C5, respectively. In order to switch to the double voltage circuit where the output is synthesized, when the NO contact point and AC 220V are input, between the two capacitors (C4, C5) and the input terminal (b) on one side of the rectifier 41 is electrically opened, the capacitor C4 Is connected to the c stage of the rectifier circuit 41, the NC contact is configured to switch to a double voltage circuit, and as the AC 110V or AC 220V is input, a signal is received from the system control unit 32 to be described later and the switch A relay coil 61 for switching (s / w) to a NO contact or an NC contact is configured.

In addition, a voltage sensing unit 50 for sensing whether the input power is AC 110V or AC 220V is connected to the output side of the voltage rectifying unit 40. That is, the voltage detector 50 divides the voltage divider resistors R1 and R2 connected in parallel to the output side of the voltage rectifier 40 so as to divide the magnitude of the DC voltage rectified by the voltage rectifier 40, and the voltage divider resistor ( A / D input port IN of the system controller 37 is connected between the voltage divider R1 and R2 to input a voltage signal corresponding to the voltage divided by R1 and R2 to the system controller 37. It consists of a signal line 51 connected to.

Here, the resistance values of the divided resistors R1 and R2 are set to input about 2V with respect to DC 150V. Therefore, the system controller 37 to be described later determines that the current input voltage is 110V when the voltage value input to the A / D input port IN is 2.5V or less, and the voltage input to the A / D input port IN. If the value is 2.5V or more, it determines that the current input voltage is AC 220V, and detects the level of the input commercial AC voltage.

Meanwhile, the inverter driving circuit unit 30 outputs a switching signal for outputting a switching signal for conducting the switching elements Q1 to Q6 of the inverter unit 20 based on the rotation pulse output from the position detection unit 23. And the duty ratio is set and output based on the operation information of the load operated by the motor 21, while the input voltage is sensed through the voltage sensing unit 50 and the voltage rectifying unit 40 is independent of the input voltage. The system control unit 37 for switching the circuit of the voltage rectifying unit 40 so that approximately 300 V is outputted from the control unit, and on / off to control the motor 21 at a rotational speed according to the duty ratio output from the system control unit 37. The PWM oscillator 35 outputs a waveform having a different ratio, and the waveform output from the PWM oscillator 35 and the switching signal output from the switching signal generator 34 are synthesized, and the switching elements of the inverter unit 20 ( Q1-Q6) to the drive unit 32 to turn on / off It consists of a waveform synthesis section 36 for output.

Hereinafter, the operation and effects of the inverter driving system according to the present invention will be described with reference to the aforementioned components and FIGS. 3 and 4.

Currently, inverter drive systems are gradually adopted in large home appliances such as washing machines, refrigerators, and air conditioners. That is, in the case of the washing machine, it is possible to finely control the rotation speed of the pulsator to implement a suitable washing program according to the type and amount of various laundry, thereby reducing the thermal damage and twist, and reduce the amount of electricity and water. In addition, in the case of the refrigerator, the operation speed of the compressor can be finely controlled, and according to the amount of food and the external environment, it can be rapidly frozen or run at a constant speed at a low rotational speed to decrease the width of the temperature change and increase the freshness, power consumption and noise. Can be reduced. In the case of the air conditioner, if the difference between the room temperature and the set temperature is large, the compressor may be rapidly cooled by rotating the compressor at high speed, and in the case of bedtime, the compressor may be rotated at a low speed to keep the indoor temperature constant and reduce power consumption.

The present invention is well applied to large home appliances equipped with such an inverter drive system.

First, when the input power is applied, it is rectified by the rectifier circuit 41 of the voltage rectifier 40, smoothed by the smoothing circuit 42, and output as a DC voltage.

At this time, the voltage corresponding to the input voltage is divided by the voltage divider resistors R1 and R2 through the voltage sensing unit 50 connected to the output side of the voltage rectifying unit 40 and applied to the system controller 37.

When the input voltage is 2.5V or less, the system controller 37 determines the level of the current input voltage as AC 110V, and outputs a control signal so that the switch S / W of the circuit switching unit 60 is switched to the NO contact point. (See Fig. 3).

Accordingly, a signal voltage corresponding to the control signal is applied to the relay coil 61 by the buffer 62. As the signal voltage is applied to the relay coil 61, the switch S / W of the circuit switching unit 60 is switched to the NO contact, thereby forming a double voltage circuit.

Therefore, the voltage rectified by the rectifier 41 is charged to each of the capacitors C4 and C5 and synthesized at the time of discharge to output approximately DC 300V.

In addition, when the input voltage is 2.5V or more, the system control unit 37 determines the level of the current input voltage as AC 220V, and the NC contact state without switching the switch S / W of the circuit switching unit 60. (See FIG. 4)

As a result, between the two capacitors C4 and C5 and between the input terminal b on one side of the rectifier 41 is electrically opened, and the capacitor C is connected to the C terminal of the rectifier circuit 41 to form a double voltage circuit.

Therefore, the voltage rectified by the rectifier 41 is charged and discharged to the capacitor C4 to output approximately DC 300V.

In this way, the approximately DC 300V output from the voltage rectifying unit 40 is converted into three phases by the inverter unit 20 switched by the control signal of the inverter driving circuit unit 30 and supplied to the variable speed motor 21.

That is, the system control unit 37 of the inverter driving circuit unit 30 sets the duty ratio based on the operation information of the load operated by the variable speed motor 21 and outputs the duty ratio. Accordingly, the PWM oscillator 35 outputs a waveform having a different on / off ratio in order to control the variable speed motor 21 at a rotational speed according to the duty ratio output from the system controller 37.

On the other hand, the position detection unit 23 outputs a rotation pulse corresponding to the rotor position of the variable speed motor 21. Accordingly, the switching signal generator 34 outputs a switching signal for conducting the switching elements Q1 to Q6 of the inverter unit 20 based on the rotation pulse output from the position detection unit 23.

Accordingly, the waveform synthesis unit 36 synthesizes the waveform output from the PWM oscillation unit 35 and the switching signal output from the switching signal generator 34 to turn on / off the switching elements Q1-Q6 of the inverter unit 20. A signal is output to the driver 32 for turning off.

Accordingly, the driving unit 32 turns on / off the six semiconductor switching elements Q1 to Q6 constituting the inverter unit 20 to supply and drive three-phase power to the variable speed motor 21.

As described in detail above, according to the present invention, the inverter voltage is rated by the inverter driving system due to user's carelessness by sensing the level of the input voltage and automatically switching the circuit of the voltage rectifying unit of the inverter driving system based on the detected input voltage level. Even if a higher level voltage is applied, the system can be prevented from being damaged due to overvoltage, and the system can be stably operated.

Claims (2)

A voltage rectifying unit for rectifying and smoothing the commercial AC voltage and outputting the inverter; an inverter unit converting the DC voltage output from the voltage rectifying unit into an AC voltage having an arbitrary amplitude and an arbitrary frequency; and an AC voltage converted by the inverter unit. In the voltage automatic switching device of the inverter drive system having a motor driven by driving the A voltage detector for dividing the DC voltage output from the voltage detector so as to sense a level of an applied commercial AC voltage; Judging the level of the commercial AC voltage applied based on the voltage value divided by the voltage sensing unit and outputs a control signal for backing the DC voltage according to the applied commercial AC voltage when the level is lower than the currently set commercial AC voltage System control unit And a circuit switching unit for switching a voltage circuit of the voltage rectifying unit to output a backed DC voltage suitable for driving the motor when a control signal is applied from the system control unit. The method of claim 1, wherein the circuit switching unit A NO contact connected between a bridge rectifier of the voltage circuit unit and a smoothing circuit connected in parallel to an output terminal of the bridge rectifier, the NO contact configured to electrically connect between two capacitors of the smoothing circuit and an input terminal of the bridge rectifier; An NC contact configured to electrically open between the two capacitors of the smoothing circuit and one input terminal of the bridge rectifier, while one capacitor is connected in parallel to the output terminal of the bridge rectifier, and a switch according to the control signal of the system controller. Or a relay coil electrically connected to the system control unit so as to be switched to an NC contact.