KR102007851B1 - Power transforming apparatus and air conditioner including the same - Google Patents

Abstract

The present invention provides a rectifying unit for rectifying an AC voltage input from an AC power source, a DC link capacitor charged with an output voltage of the rectifying unit, provided between the AC power source and the rectifying unit and charged until a voltage predetermined in the DC link capacitor is charged. The magnitude of the voltage charged in the charging resistor to which the AC voltage is applied, the relay connected in parallel with the charging resistance, the driving circuit for supplying a constant voltage to the relay and the DC link capacitor, and according to the determined voltage It relates to a power converter including a relay control unit for controlling the constant voltage supplied to the relay.

Description

Power transforming apparatus and air conditioner including the same {Power transforming apparatus and air conditioner including the same}

The present invention relates to a power converter and an air conditioner including the same, specifically, it is possible to prevent the inrush current generated when the initial power is applied.

Generally, the compressor of an air conditioner uses a motor as a drive source. These motors are supplied with alternating current power from a power converter. It is common for such a power converter to mainly comprise a rectifier, a power factor controller, and an inverter converter.

First, the commercial voltage of the AC output from the commercial power supply is rectified by the rectifier. The voltage after the rectification is adjusted and smoothed to the desired voltage by the power factor controller, the power factor can be improved through this process.

After this power factor is improved, the voltage is supplied to a power converter such as an inverter. At this time, the power converter generates AC power for driving the motor by using the voltage after the power factor improvement.

Such a power factor control unit constitutes a DC-DC converter. In this case, a driving unit (for example, a driver IC) for driving a switching element used in the converter includes an overcurrent protection circuit to prevent burnout of the switching element.

The overcurrent protection circuit senses a current flowing through the switching device and uses a method of shutting off the driving of the switching device when it senses that the switching device has a predetermined voltage or more.

Referring to FIG. 1, which is a related art, a method of cutting off a current using a relay when an overcurrent or an overvoltage occurs is illustrated. On / Off of the relay is controlled by the controller Micom and the buffer IC.

That is, when information indicating that an overcurrent or overvoltage has occurred in the circuit is input to the controller Micom, the controller Micom transmits a relay OFF signal to a buffer IC through a port provided in the controller Micom. Buffer IC). The buffer IC receives a signal from the controller and amplifies the current. The buffer IC delivers the signal from the controller to the relay.

In summary, FIG. 1 corresponds to a method of controlling a relay in a software manner. The method as shown in FIG. 1 has a disadvantage of high space and cost. This requires easy implementation and a simple relay control scheme.

An object of the present invention is to provide a power converter that determines ON / OFF of a relay only by a hardware configuration.

Another object of the present invention is to provide a power converter that can easily secure space.

Another object of the present invention is to provide a power conversion device with low cost.

In addition, an object of the present invention is to provide a power conversion device that can reduce the power consumed by the charge resistance.

The present invention provides a rectifying unit for rectifying an AC voltage input from an AC power source, a DC link capacitor charged with an output voltage of the rectifying unit, provided between the AC power source and the rectifying unit, and provided to the DC link capacitor. The magnitude of the voltage charged in the charging resistor to which the AC voltage is applied, the relay connected in parallel with the charging resistance, the driving circuit for supplying a constant voltage to the relay, and the DC link capacitor until a predetermined voltage is charged, It provides a power converter including a relay control unit for controlling the constant voltage supplied to the relay in accordance with the magnitude of the determined voltage, it is possible to determine the ON / OFF of the relay only by the hardware configuration and the space is easy to effect have.

In addition, in one embodiment of the present invention, the relay control unit, measuring the voltage stored in the DC link capacitor, and receives a signal from the comparison unit and the comparison unit for comparing the measured value with a predetermined reference value ON / OFF control The present invention provides a power conversion device including a transistor, and it is possible to determine the ON / OFF state of a relay only by a hardware configuration.

In an embodiment of the present invention, when the voltage stored in the DC link capacitor is greater than a predetermined reference value, the comparator transmits an ON signal to the transistor, and the voltage stored in the DC link capacitor is equal to or less than a predetermined reference value. In this case, the comparator provides a power converter, characterized in that to transmit an OFF signal to the transistor.

In addition, in one embodiment of the present invention, the output terminal of the comparison unit provides a power conversion device, characterized in that connected to the base terminal of the transistor.

In addition, in one embodiment of the present invention, the relay provides a power conversion device, characterized in that provided between the driving circuit and the transistor.

In addition, according to an embodiment of the present invention, when the transistor receives the ON signal from the comparison unit, a current converter is characterized in that the current applied to the collector flows to the emitter.

In addition, in an embodiment of the present invention, an AC voltage supplied from the AC power supply is provided to the power converter, characterized in that applied to the relay.

In addition, in one embodiment of the present invention, the comparison unit, a voltage determining unit for measuring the voltage charged in the DC link capacitor and converts it to a predetermined level and a comparator for comparing the value converted in the voltage determination unit with a predetermined reference value It provides a power converter comprising a.

According to an embodiment of the present invention, when the converted value is larger than the predetermined reference value, the comparator provides an power converter, characterized in that to apply an ON signal to the transistor.

According to an embodiment of the present invention, when the converted value is smaller than the predetermined reference value, the comparator provides an power converter, characterized in that to apply an OFF signal to the transistor.

In addition, in one embodiment of the present invention, the power converter, characterized in that applied to the motor constituting the compressor of the air conditioner including an outdoor unit having an indoor unit and a compressor.

The present invention has the effect of providing a power conversion device for determining the ON / OFF of the relay only by the hardware configuration.

In addition, the present invention has the effect of providing a power converter easy to secure space.

In addition, the present invention has the effect of providing a low-cost power converter.

In addition, the present invention has the effect of reducing the power consumed in the charge resistance.

1 shows a conventional technique for controlling a relay.
Figure 2 shows that a relay control unit is included according to an embodiment of the present invention.
3 illustrates a change in current flow in a circuit according to the operation of the relay controller.
4 graphically illustrates the generation of inrush current.
5 is a graph illustrating inrush current generated according to the operation of the relay controller.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention. On the other hand, the configuration or control method of the device to be described below is not intended to limit the scope of the present invention, but to describe the embodiment of the present invention, the same reference numerals are used throughout the specification the same components Indicates.

2 illustrates a power conversion apparatus according to an embodiment of the present invention.

The circuit shown in FIG. 2 includes an AC power supply 10, a rectifier 20 for rectifying the AC voltage generated by the AC power supply 10 to a DC voltage, and a DC to which the DC voltage generated by the rectifier 20 is applied. The link capacitor 30, the AC power source 10 and the rectifier 20 is composed of a charge resistor 40 is provided.

When the AC voltage first applies the voltage to the rectifier 20, a phenomenon occurs in which the value of the current rises instantaneously. If the current value increases instantaneously, the rectifier 20 and the DC link capacitor 30 may be burned out.

This is shown in FIG. In the graph shown above in FIG. 4, an enlarged view of the moment of applying the voltage to the rectifier 20 for the first time is shown in the graph below. It can be seen that when the voltage is first applied, the value of the inrush current increases and then gradually decreases.

In order to prevent the instantaneous increase in the value of the inrush current, the charging resistor 40 is installed between the AC power supply 10 and the rectifier 20. Since voltage is applied to the charging resistor 40, the charging resistor 40 consumes a predetermined amount of energy, thereby lowering the value of the initial inrush current.

However, the charging resistor 40 has no useful value except when the voltage is first applied to the rectifier 20 and the DC link capacitor 30 in the AC power supply 10. That is, since the voltage is continuously applied even after the value of the initial inrush current is lowered, unnecessary power is consumed.

In order to solve the above problems, unlike the prior art, an embodiment of the present invention further includes a relay 50, a relay controller 60, and a driving circuit 65 in the circuit.

The relay 50 is connected in parallel with the charging resistor 40. That is, when the relay 50 does not operate, the AC voltage generated by the AC power source 10 is applied to the charging resistor 40, but when the relay 50 operates, the AC voltage generated by the AC power source 10 It is applied to the relay 50 and no current flows to the charging resistor 40.

The relay 50 is theoretically composed of a conductor whose resistance is close to zero, and preferably has a conductor having a resistance value which is very small compared to the resistance value of the charging resistor 40. This is because the AC voltage generated by the AC power source 10 must be applied to the relay 50 when the relay 50 operates.

In addition, the relay 50 is connected to a driving circuit 65 capable of supplying a constant voltage. That is, the constant voltage generated in the driving circuit 65 is connected in series to be supplied to the relay 50.

The relay 50 is composed of an inductor 51 and a relay switch 53. The inductor 51 and the relay switch 53 are connected in parallel, and the inductor 51 becomes an electromagnet that forms a magnetic field when a current is applied.

When a constant voltage generated in the driving circuit 65 is applied to the inductor 51, the inductor 51 becomes an electromagnet and affects the relay switch 53 connected in parallel. The relay switch 53 made of a conductor receives a magnetic force in the inductor 51 direction by the magnetic field generated by the inductor 51.

Therefore, as shown in FIG. 2, when a constant voltage generated from the driving circuit 65 is applied to the inductor 51, the relay switch 53 is operated, and the AC voltage generated from the AC power source 10 is the relay switch 53. Is applied to. That is, due to the operation of the relay switch 53, the voltage is not applied to the charging resistor 40 or a very small voltage is applied.

Since the driving circuit 65 generates the constant voltage corresponds to the related art, description thereof will be omitted.

Next, look at the relay control unit 60 for controlling the constant voltage applied to the relay 50.

The relay controller 60 determines the magnitude of the voltage charged in the DC link capacitor 30 and controls the constant voltage applied to the relay 50 according to the magnitude of the stored voltage.

When the DC link capacitor 30 is charged with a predetermined voltage or more, the relay controller 60 controls the constant voltage generated by the driving circuit 65 to be applied to the relay 50.

On the contrary, when the voltage is not charged to the DC link capacitor 30 by a predetermined amount, the relay controller 60 controls the constant voltage generated by the driving circuit 65 not to be applied to the relay 50.

The relay controller 60 constantly checks the magnitude of the voltage charged in the DC link capacitor 30 and controls the relay 50 based on the checked contents.

The relay controller 60 includes a comparator 61 and a transistor 63. The comparator 61 measures the magnitude of the voltage charged in the DC link capacitor 30 and compares the measured value with a predetermined reference value. The transistor 63 receives a signal generated by the comparator 61 and is controlled to be ON or OFF according to the type of the signal generated by the comparator 61.

The output terminal of the comparator 61 is connected to the base terminal of the transistor 63. That is, the transistor 63 is controlled to be ON or OFF in accordance with the signal of the comparator 61.

The comparator 61 measures the magnitude of the voltage charged in the DC link capacitor 30 and then converts the voltage decision part 611 to a predetermined level and a comparator comparing the numerical value converted in the voltage decision part with a predetermined reference value. 613.

The magnitude of the voltage chargeable to the DC link capacitor 30 depends on the capacity of the DC link capacitor 30. Thus, for example, when a high voltage of 10000 V or more is charged, the comparator 613 may exceed the range that can be judged or have a high possibility of damage. On the contrary, when the low voltage is charged, the comparator 613 may not be included in the range that can be determined.

The voltage determining unit 611 measures the magnitude of the voltage charged in the DC link capacitor 30 and converts the voltage into a voltage within a range that the comparator 613 can measure. That is, the voltage determining unit 611 steps down the voltage applied to the DC link capacitor 30 when the voltage is very large and applies it to the comparator 613. do.

The voltage information converted by the voltage determining unit 611 is applied to the comparator 613, and the applied information is compared with a preset reference value stored in the comparator 613.

When the applied voltage information is higher than the preset reference value, the ON signal is emitted from the output terminal of the comparator 613. When the applied voltage information is lower than the preset reference value, the OFF signal is emitted from the output terminal of the comparator 613.

The output terminal of the comparator 613 is connected to the base terminal of the transistor 63. That is, the ON or OFF signal emitted from the output terminal of the comparator 613 is input to the base terminal of the transistor 63.

On the other hand, the relay 50 is provided between the driving circuit 65 and the transistor 63. Specifically, one end of the relay 50 is connected in series with the drive circuit 65 and the other end of the relay 50 is connected with the collector of the transistor 63.

When the ON signal generated by the comparator 613 is applied to the transistor 63, the constant voltage generated by the driving circuit 65 applied to the collector of the transistor 63 flows to the emitter of the transistor 63. The emitter is connected to or grounded with another circuit.

That is, current flows sequentially along the drive circuit 65, the relay 50, the collector of the transistor 63, and the emitter of the transistor 63. As a result, the current flows through the relay 50 so that the relay switch 53 operates.

When the OFF signal generated by the comparator 613 is applied to the transistor 63, the constant voltage generated by the driving circuit 65 applied to the collector of the transistor 63 does not flow to the emitter of the transistor 63. That is, the collector and emitter are not in communication with each other.

Therefore, no current flows through the relay 50 and the relay switch 53 does not operate.

With reference to Figures 3 and 5 will be described the operation of the circuit over time.

3 shows two paths through which current flows in the AC power source 10. There is a path (1) indicated by a dotted line and a path (2) indicated by a solid line. Path (1) shows that the AC voltage generated from the AC power source 10 is applied to the charging resistor 40, and path (2) shows that the AC voltage is applied to the relay 50.

When the AC power source 10 first operates, the AC voltage passes through the charging resistor 40 and the rectifier 20 and finally the DC voltage is applied to the DC link capacitor 30. The charging resistor 40 is installed in order to prevent a phenomenon in which the inrush current generated at the moment of the first operation of the AC power supply 10 rises sharply.

Looking at Figure 5 it can be seen that the value of the input current is large at the beginning of the section (1). After that, it can be seen that the current level gradually stabilizes with time. In summary, the charging resistor 40 serves to lower the current value flowing when the voltage is first applied.

The DC link capacitor 30 is charged by the operation of the AC power supply 10. After a predetermined time, the DC link capacitor 30 is near full charge. However, when the DC link capacitor 30 approaches full charge, as shown in FIG. 5, since the current value is already stabilized, the voltage does not need to be applied to the charge resistor 40.

Therefore, the relay 50 is operated when the DC link capacitor 30 is charged by a predetermined level through the voltage determining unit 611 that determines the charging degree of the DC link capacitor 30 at all times. Detailed description of the operation of the relay 50 is as described above.

When the DC link capacitor 30 is charged by a predetermined level, the relay controller 60 controls the constant voltage generated by the driving circuit 65 to be applied to the relay 50.

When a constant voltage is applied to the relay 50, the relay switch 53 is operated and current flows in the path (2).

Looking at Figure 5, it can be seen that the value of the current is slightly increased at the time of the relay (50) starting point ((2) section start time). However, since the DC link capacitor 30 is close to the full charge state, the current value is considerably lower than the start point of the section (1).

That is, when the DC link capacitor 30 is fully charged to some extent, even if no current flows in the charging resistor 40, the value of the current does not rapidly increase. Since the value of the current does not rise sharply, it is possible to prevent the burnout of various elements in the circuit.

In summary, in the conventional case, a voltage was always applied to the charging resistor 40 regardless of whether the DC link capacitor 30 was charged. Although the charging resistor 40 is installed for the moment when the AC power supply 10 operates for the first time, it corresponds to a configuration that consumes unnecessary power except for the moment of operation for the first time.

The voltage determining unit 611 checks the magnitude of the voltage charged in the DC link capacitor 30 at all times, and controls the operation of the relay 50 in real time according to the change in the magnitude of the charged voltage.

In one embodiment of the present invention, the role of the charging resistor 40 is saved, but when the role of the charging resistor 40 is terminated, there is an effect of reducing the amount of power continuously consumed by the charging resistor 40.

Unlike the conventional method, the above operations may be implemented using only hardware components such as the driving circuit 65, the transistor 63, and the comparator 613. Therefore, it does not use a separate control unit (micom) or a buffer IC (Buffer IC), so it is relatively easy to implement a circuit, can reduce the manufacturing cost, and is superior to the conventional technology in terms of securing space in a circuit board (PCB) Do.

That is, since the operation circuit independent of the control unit is formed, it is free from failure of other components such as the control unit. In other words, a malfunction of the software does not occur.

On the other hand, the present invention can be applied to any circuit that uses a component sensitive to the inrush current applied initially.

In one embodiment of the present invention, the circuit can be applied to an air conditioner.

The air conditioner corresponds to a device for purifying air to cool or heat a room, and is generally divided into an indoor unit and an outdoor unit. The outdoor unit includes a compressor for compressing the gas refrigerant, the compressor compresses the refrigerant by using the rotational force of the motor.

The circuit structure according to the embodiment of the present invention can be applied to the operation of the motor using electricity as a power source.

It is possible to extend the lifespan of the electronic components used to operate the motor, and to reduce the area of the circuit board (PCB), there is an advantage that the product size adjustment is more free.

The present invention may be practiced in various forms and is not limited to the above-described embodiment. Therefore, if the modified embodiment includes the components of the claims of the present invention will be seen as belonging to the scope of the present invention.

100: power inverter
10: AC power
20: rectifier
30: DC link capacitor
40: charge resistance
50: relay 51: inductor 53: relay switch
60: relay control unit 61: comparison unit 611: voltage measurement unit
613: comparator 63: transistor 65: drive circuit

Claims (11)

A rectifier for rectifying an AC voltage input from an AC power source;
A DC link capacitor charged with the output voltage of the rectifier;
A charging resistor provided between the AC power source and the rectifier and configured to apply the AC voltage until a predetermined voltage is charged in the DC link capacitor;
A relay connected in parallel with the charging resistor;
A driving circuit for supplying a constant voltage to the relay; And,
Determining the magnitude of the voltage charged in the DC link capacitor, and controlling the constant voltage supplied to the relay according to the determined voltage, to determine the level of charge of the DC link capacitor at all times and to the DC link capacitor After measuring the magnitude of the charged voltage through the voltage determination unit for converting the comparator to a voltage level within the measurable range, the comparator for comparing the voltage level converted in the voltage determination unit with a predetermined reference value, and through the inductor of the relay And a relay controller connected to the driving circuit and having a transistor for selectively connecting the driving circuit and the relay so that the constant voltage generated in the driving circuit is applied to the inductor of the relay according to the output signal of the comparator. ,
The voltage determining unit steps down when the voltage charged in the DC link capacitor is larger than the comparable range, and applies the comparator when the charged voltage is smaller than the comparable range. Power converter characterized in that. delete The method of claim 1,
The comparator transmits an ON signal to the transistor when the voltage level converted by the voltage determining unit is greater than a predetermined reference value. The comparator transmits an ON signal to the transistor when the voltage level converted by the voltage determining unit is equal to or smaller than a predetermined reference value. A power converter characterized by transmitting an OFF signal to a transistor. The method of claim 1,
The output terminal of the comparator is connected to the base terminal of the transistor. The method of claim 1,
And the relay is provided between the driving circuit and the transistor. delete delete delete delete delete The method according to any one of claims 1 and 3 to 5,
The power converter, characterized in that applied to the motor constituting the compressor of the air conditioner including an outdoor unit having an indoor unit and a compressor.

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