JPH0688197U - DC power supply - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide a DC power supply device capable of suppressing an inrush current when an AC power supply is turned on and stably performing initial charging of a smoothing capacitor. According to the present invention, in a three-phase full-wave rectification type DC power supply device, a voltage detector and a current detector for detecting a DC voltage and a DC current of the DC power supply device and an initial charging voltage of the smoothing capacitor are set. An initial charging voltage setter, a phase control circuit that calculates a phase reference of the self-extinguishing element, an initial charging completion detection circuit that determines completion of initial charging from the detected DC voltage, and the detected DC current. A gate cutoff command circuit that determines the necessity of gate cutoff,
Since it has a gate control circuit for controlling the gate of the self-extinguishing type device by the output signals of the phase control circuit, the initial charge completion detection circuit, and the gate cutoff command circuit,
The inrush current at the initial charging of the smoothing capacitor can be suppressed without using a current limiting resistor, and since the smoothing capacitor is initially charged by the main circuit power supply, the contact between the control circuit and the main circuit is prevented. You can

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a DC power supply device, and more particularly to a three-phase full wave rectification type DC power supply device.

[0002]

[Prior art]

 Conventionally, each inverter has its own rectifier, but in equipment that uses multiple inverters, each inverter does not have its own rectifier, but one rectifier for multiple inverters. Since it is advantageous in terms of space and price of installation place, a DC power supply device as a common power supply has been introduced. For loads that do not require regenerative operation, the DC power supply is composed of a unidirectional diode bridge and outputs DC voltage after three-phase full-wave rectification. However, the capacity of this three-phase full-wave rectification type DC power supply tends to increase year by year as the capacity of the inverter and mechanical equipment increases.

By the way, in a DC power supply device composed of a diode bridge, an inrush current flows as charging of a smoothing capacitor at the same time when AC power is turned on. If this inrush current exceeds the allowable current of the main circuit element and the smoothing capacitor, the main circuit element and the smoothing capacitor will be destroyed.Therefore, insert a current limiting resistor in the DC main circuit to suppress the inrush current and smooth the current. When the capacitor was fully charged, this current limiting resistor was short-circuited with a contactor.

However, as the capacity of the DC power supply becomes larger, the current limiting resistor also becomes larger, and heat generation and installation space have become problems. In addition, the larger the capacity of the DC power supply, the larger the energizing current, and the larger the contactor that short-circuits the current limiting resistor. Therefore, depending on the capacity, it is necessary to use a circuit breaker. In addition, if the smoothing capacitor is charged from the control power supply, there is a risk of contact between the main circuit and control circuit.

[0005]

[Problems to be solved by the device]

 As described above, the inrush current that flows when the AC power is turned on may destroy the main circuit element or the smoothing capacitor, and the current limiting resistor for suppressing the inrush current and its short-circuit contactor have the capacity of the DC power supply unit. As it gets bigger, it becomes bigger, and heat generation and installation space have become problems. Furthermore, charging the smoothing capacitor from the control power supply poses the problem that there is a risk of contact between the main circuit and control circuit, and a solution has been sought.

The present invention has been made to solve the above-mentioned problems, and its purpose is to suppress the inrush current when the AC power is turned on and to make it possible to perform stable initial charging of the smoothing capacitor. To provide a power supply device.

[0007]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention is a three-phase full-wave rectification type DC power supply device equipped with a mixed bridge of a diode and a self-extinguishing type element and a smoothing capacitor, and detects the DC voltage of the direct current power supply device. Voltage detector, a current detector for detecting the DC current of the DC power supply device, an initial charge voltage setter for setting the initial charge voltage of the smoothing capacitor, and a phase reference for the self-extinguishing element. A phase control circuit, an initial charge completion detection circuit that determines completion of initial charge from the detected DC voltage, a gate cutoff command circuit that determines necessity of gate cutoff based on the detected DC current, and the phase control circuit And a gate control circuit for controlling the gate of the self-extinguishing type element by the output signal of the initial charge completion detection circuit and the gate cutoff command circuit. To.

[0008]

[Action]

 The initial charging voltage of the smoothing capacitor of the DC power supply is set by the initial charging voltage setter and input to the ramp function circuit. The initial charging voltage reference gradually changes to the set value according to the rate of the ramp function circuit, and is input to the voltage controlled amplifier. In the voltage control amplifier, the deviation between the output voltage of the DC power supply detected by the voltage detector and the reference value is obtained, and the deviation is input to the current limiting circuit. The output current of the DC power supply detected by the current detector is input to the current limiting circuit and the gate cutoff command circuit, respectively.In the current limiting circuit, the current reference is set so that it is below the allowable current value of the main circuit element and the smoothing capacitor. Limited. The current reference is input to the phase control circuit, and the reference of the gate signal of the necessary main circuit element is calculated and output to the gate control circuit. On the other hand, the output voltage is input to the initial charge completion detection circuit, and when it is determined that the initial charge is completed, the initial charge completion detection circuit outputs a completion signal to the gate control circuit. If the gate cutoff command circuit determines that the output current is abnormal, it outputs a gate cutoff command to the gate control circuit. The gate control circuit outputs the gate control signal to the main circuit element until the completion signal is input, and blocks the gate when the cutoff command is input.

[0009]

【Example】

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram of a three-phase full-wave rectification type DC power supply device which is an embodiment of the present invention. In the figure, 1 is a voltage detector that detects the DC voltage V of the DC power supply device, 2 is a current detector that detects the DC current I _d , and 3 is an initial charging voltage that sets the initial charging voltage V _F of the smoothing capacitor C. Setting device, 4 is a ramp function circuit, 5 is a voltage control amplifier, 6 is a current limiting circuit, 7 is a phase control circuit, 8 is an initial charge completion detection circuit that determines the completion of initial charge from DC voltage V, and 9 is a DC current. A gate cutoff command circuit 10 for judging the necessity of gate cutoff from I _d controls the gate of the main circuit element by the output signals of the phase control circuit 7, the initial charge completion detection circuit 8 and the gate cutoff command circuit 9. It is a gate control circuit. In addition, 11 is a transformer, 12 is a circuit breaker, D is a diode, and T is a self-extinguishing type element.

Next, the operation of this embodiment will be described. The main circuit of the DC power supply is composed of a mixed bridge of a diode D and a self-extinguishing element T, and is connected to an AC power supply (not shown). Switching on / off of the AC power supply is performed by the input side breaker 12 of the transformer 11. The DC voltage V of the DC power supply device is detected by the voltage detector 1 and input to the initial charge completion detection circuit 8 and the voltage control amplifier 5. The DC current I _d of the DC power supply device is detected by the current detector 2 and input to the current limiting circuit 6 and the gate cutoff command circuit 9.

The initial charging voltage V _F of the smoothing capacitor C is set by the initial charging voltage setter 3, and the initial charging voltage reference V _R is input to the ramp function circuit 4. The output V _R ′ of the ramp function circuit 4 is input to the voltage control amplifier 5, and the voltage control amplifier 5 obtains the deviation ΔV between the output V _R ′ of the ramp function and the DC voltage V and inputs it to the current limiting circuit 6. Be done.

In the current limiting circuit 6, the current reference I _R is determined so as to be equal to or less than the allowable current value I _{L of} the preset main circuit element, the diode D, the self-extinguishing element T, and the smoothing capacitor C. , The current reference I _R is input to the phase control circuit 7. In the phase control circuit 7, the phase reference P of the self-extinguishing element T is calculated according to the current reference I _R and is input to the gate control circuit 10. The gate control circuit 10 calculates the gate timing of the self-extinguishing element T according to the phase reference P and outputs a gate signal G to the self-extinguishing element T. As a result, the direct current I _d is limited and the smoothing capacitor C is gradually charged.

The initial charge completion detection circuit 8 determines whether the initial charge is completed from the DC voltage V. When the initial charge is completed, the initial charge completion signal E is output to the gate control circuit 10, and the gate control circuit 10 The gate of the self-extinguishing element T is switched and controlled so as to perform three-phase full-wave rectification. When the DC current I _d becomes an abnormal value, the gate cutoff command circuit 9 determines that the DC power supply device is abnormal, and the gate cutoff command B is output to the gate control circuit 10, which causes the gate control circuit 10 to perform its own operation. Block the gate of arc-extinguishing element T 1. Although the gate turn-off thyristor is used as the self-arc-extinguishing element T in the above embodiment, the invention is not limited to this.

[0014]

[Effect of device]

 As described above, according to the present invention, it is possible to suppress the inrush current at the initial charging of the smoothing capacitor without using a current limiting resistor, and prevent the main circuit element and the smoothing capacitor from being destroyed by the inrush current. be able to. Also, since the smoothing capacitor is initially charged by the main circuit power supply, it is possible to prevent contact between the control circuit and the main circuit, and by shutting off the gate of the self-extinguishing element when the direct current is abnormal. It is possible to prevent the accident from spreading to the power supply system side.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of an embodiment of the present invention.

[Explanation of symbols]

1 ... Voltage detector, 2 ... Current detector, 3 ... Initial charging voltage setting device, 4 ... Ramp function circuit, 5 ... Voltage control amplifier, 6 ...
Current limit circuit, 7 ... Phase control circuit, 8 ... Initial charge completion detection circuit, 9 ... Gate cutoff command circuit, 10 ... Gate control circuit, 11 ... Transformer, 12 ... Breaker, C ... Smoothing capacitor, D ... Diode, T ... Self-extinguishing element.

Claims (1)

[Scope of utility model registration request] 1. A three-phase full-wave rectification type DC power supply device comprising a mixing bridge of a diode and a self-extinguishing type element and a smoothing capacitor, a voltage detector for detecting a DC voltage of the DC power supply device, and the DC power supply. A current detector that detects a direct current of the device, an initial charging voltage setting device that sets an initial charging voltage of the smoothing capacitor, a phase control circuit that calculates a phase reference of the self-extinguishing element, and the detected An initial charge completion detection circuit that determines the completion of initial charge from a DC voltage, a gate cutoff command circuit that determines the necessity of gate cutoff from the detected DC current, the phase control circuit, an initial charge completion detection circuit, and a gate cutoff A DC power supply device comprising a gate control circuit for controlling the gate of the self-extinguishing element according to an output signal of a command circuit.