JP2005261061A - Power supply unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the voltage ripple that may cause the flickering of an illuminator, concerning a power unit which suppresses the voltage ripple on the side of an AC power source (distribution line). <P>SOLUTION: This power supply unit comprises a rectifying circuit 2 which rectifies AC voltage, a converter 5 which supplies a switching load apparatus 6 with the rectified output voltage of this rectifying circuit 2, a boost converter 3 which boosts the rectified output voltage of the rectifying circuit 2 prior to charging a capacitor C1 in the operation-off period of the switching load apparatus 6, a discharge circuit 4 which discharges the charge of the capacitor C1 to the side of the converter 5, in the operation-on period of the switching load apparatus 6, and an ON/OFF controller 7 which controls the start and stop of the action of the boost converter 3 and the discharge circuit 4. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a power supply apparatus that performs control so that voltage fluctuation on the AC power supply side does not occur due to load fluctuation.

  Various devices are connected to the indoor distribution line along with lighting devices. These various devices include devices having a characteristic that a large current flows intermittently. For example, as shown in FIG. 5, when the switching load device 101 and the lighting device 102 are connected to the distribution line, and the switching load device 101 is repeatedly turned on and off, the current flowing through the distribution line also varies accordingly. And since the voltage drop by the impedance of a distribution line fluctuates, the applied voltage with respect to the illuminating device 102 also fluctuates. For example, in a page printer, a large amount of power is required at the time of transfer and fixing, and this state is performed every time paper is fed, and the current is repeatedly turned on and off at a cycle corresponding to the print speed. Thereby, as described above, the applied voltage of the lighting device 102 varies, and the brightness varies. That is, flickering of lighting occurs.

  Regulations on this flickering of lighting are about to be implemented. For example, the flicker standard by IEC (International Electrotechnical Commission; 1000-3-3) and IEC1000-3-11 is known.

Various switching power supply devices that control the voltage applied to the load to be constant are known, and a configuration in which switching power supply devices are connected in parallel is also known for loads with large power consumption (for example, Patent Document 1).
JP 2000-1162029 A

  Various configurations such as single-phase 100V or 200V, single-phase three-wire 100V or 200V, three-phase three-wire 200V are applied to the distribution lines, and the types and characteristics of the devices connected to the distribution lines are respectively It is often different. In this case, the lighting device can be regarded as a constant load when it is turned on, but other devices often have a variable load. In particular, in the case of the switching load device 101 as described above, the load current changes intermittently, and the voltage changes depending on the impedance of the distribution line corresponding to the change. Therefore, there is a problem in that the applied voltage to the lighting device connected to the distribution line fluctuates and flicker occurs.

  If the distribution line impedance is set to a value that is negligible, voltage fluctuation due to load current fluctuation can be reduced, but it is necessary to use a large-diameter distribution line and to provide a large-capacity transformer. It is not a solution. The switching power supply device that can maintain the output voltage constant does not include a configuration that suppresses voltage fluctuation on the AC power supply (distribution line) side. At present, no flicker regulation is implemented, and therefore no means for preventing flicker of lighting equipment due to load fluctuations has been proposed.

  An object of this invention is to prevent the flicker of the lighting equipment by the fluctuation | variation of the load current which flows into a distribution line.

    The power supply device of the present invention includes a rectifier circuit that rectifies an AC voltage, a converter that supplies a rectified output voltage of the rectifier circuit to a switching load device, and a rectified output voltage of the rectifier circuit during an operation off period of the switching load device. A boost converter that boosts and charges a capacitor, and a discharge circuit that discharges the charge of the capacitor to the converter during an operation-on period of the switching load device are provided.

  The boost converter performs the charging operation of the capacitor according to the information on the operation off of the switching load device, stops the charging operation of the capacitor according to the information of the operation on of the switching load device, and the discharge circuit includes the switching circuit. The controller includes a control unit that performs a discharge operation of the capacitor based on information on the operation of the load device and stops the discharge operation of the capacitor based on the information about the operation off of the switching load device.

  The discharge circuit has a configuration in which a discharge current of the capacitor is detected to control the transistor, and constant current discharge is performed by the transistor.

  The current flowing to the AC power supply (distribution line) side can be made substantially constant by discharging and charging the capacitor during the period of operation on and off of the switching load device connected to the AC power supply (distribution line). Therefore, the voltage fluctuation of the AC power supply (distribution line) can be suppressed and flickering of the lighting device can be prevented.

  Referring to FIG. 1, a rectifier circuit 2 that rectifies an AC voltage, a converter 5 that supplies a rectified output voltage of the rectifier circuit 2 to a switching load device 6, and an operation off period of the switching load device 6, A boost converter 3 that boosts the rectified output voltage to charge the capacitor C1 and a discharge circuit 4 that discharges the charge of the capacitor C1 to the converter 5 during the operation-on period of the switching load device 6 are provided.

  FIG. 1 is an explanatory diagram of Embodiment 1 of the present invention, showing a case where a distribution line is a three-phase three-wire system, 1 is a power supply device, 2 is a rectifier circuit, 3 is a boost converter, 4 is a discharge circuit, 5 is a converter, 6 is a switching load device, 7 is an ON / OFF control unit, 8 is a current detection unit, 9 is a reference voltage, 10 is an error amplifier, 11 is a PWM control unit, 12 is a drive circuit, 13 is a reference voltage, 14 is a comparator, 15 and 16 are resistors, Q1 and Q2 are transistors, L1 is a choke coil, D1 is a diode, and C1 and C2 are capacitors.

  The rectifier circuit 2 full-wave rectifies the 200 V three-phase AC voltage to charge the capacitor C <b> 2, and uses the terminal voltage as the input voltage of the converter 5. The converter 5 is a DC-DC converter that outputs a desired DC voltage when the switching load device 6 requires DC power, and outputs a desired AC voltage when AC power is required. A DC-AC converter is used. Further, the case where the on / off control signal on / off of the operation of the switching load device 6 is input to the ON / OFF control unit 7 will be described.

  This ON / OFF control unit 7 constitutes a control unit that controls ON / OFF of the boost converter 3 and the discharge circuit 4. When the operation in which the load current flows through the switching load device 6 is ON, the discharge circuit 4 The reference voltage 13 is controlled to a predetermined value to start the discharge operation, and the operation of the drive circuit 12 of the boost converter 3 is stopped. Further, when the switching load device 6 is turned off so that no load current flows or is small, the reference voltage 13 of the discharge circuit 4 is controlled to zero or a value close to zero to stop the discharge operation, and the boost converter 3 The operation of the driving circuit 12 is started.

  In the operation off period when the load current does not flow through the switching load device 6, the ON / OFF controller 7 controls the reference voltage 13 of the discharge circuit 4 to zero or a value close to zero, so that the transistor Q2 is in the off state. It becomes. Further, since the drive circuit 12 of the boost converter 3 is controlled to be in an operating state, on / off control of the transistor Q1 is started. That is, the operation as the boost converter 3 is started, the current is detected by the current detector 8, the difference between the voltage proportional to the current and the reference voltage 9 is obtained by the error amplifier 10 and input to the PWM controller 11, A pulse width control signal is input from the PWM control unit 11 to the drive circuit 12, and the drive circuit 12 controls the on period of the transistor Q1.

  Therefore, when the transistor Q1 is turned on, a current flows through the choke coil L1, and when the transistor Q1 is turned off, the capacitor C1 is charged via the diode D1 with the current due to the energy accumulated by the inductance of the choke coil L1. Accordingly, during the operation off period of the switching load device 6, the capacitor C1 is charged through the rectifier circuit 2, and a current flows to the AC power supply (distribution line) side.

  Further, during the operation ON period when the load current flows through the switching load device 6, the operation of the boost converter 3 is stopped by the ON / OFF control unit 7, and the reference voltage 13 of the discharge circuit 4 is controlled to a predetermined value. Therefore, the transistor Q2 is controlled so that the current flowing through the resistor 16 becomes a value determined by the reference voltage 13, and constant current discharge is performed by the charge charged in the capacitor C1. That is, when the discharge circuit 4 operates and the current supplied to the switching load device 6 via the converter 5 is the sum of the current via the rectifier circuit 2 and the constant current due to the discharge of the capacitor C1, the switching load device Even in the operation off period 6, current flows to the AC power supply (distribution line) side, so that voltage fluctuation of the AC power supply (distribution line) does not occur. Accordingly, flickering of the lighting device can be prevented.

  FIG. 2 is an explanatory diagram of voltage fluctuation on the side of the three-phase AC power supply (distribution line), showing the case where the AC power supply (distribution line) is a three-phase AC, and (a) in the conventional example An outline of a three-phase full-wave rectified voltage by a rectifier circuit proportional to the input voltage is shown, and (b) shows an outline of an input current flowing on the three-phase AC power supply (distribution line) side. Further, (c) shows the switching load device on (operation) and off (pause). (D) shows an outline of a three-phase full-wave rectified voltage by the rectifier circuit 2 proportional to the input voltage according to the embodiment of the present invention, and (e) shows a three-phase AC power supply (distribution) according to the embodiment of the present invention. An outline of the input current flowing in the (electric wire) side is shown.

  In the conventional example, as shown in (b), the input current in the rest (off) period of the switching load device, that is, the current on the AC power supply (distribution line) side is zero or a value close thereto. As a result, the voltage on the AC power supply (distribution line) side rises as indicated by a1 and a2 in FIG.

  On the other hand, according to the embodiment of the present invention, as shown in (e), during the pause (off) period of the switching load device, a current is passed through the capacitor C1 by the boost converter 3, and the AC power supply corresponding to the current is supplied. Since the current on the (distribution line) side can flow, voltage fluctuations can be prevented from occurring as indicated by d1 and d2 in (d). Therefore, flickering of lighting equipment connected to the AC power supply (distribution line) can be prevented.

  FIG. 3 shows the current and operation of each part of the embodiment of the present invention. (A) corresponds to (e) in FIG. 2, and (b) corresponds to (c) in FIG. . (C) shows the operation (ON) and pause (OFF) of the boost converter 3, (d) shows the operation (ON) and pause (OFF) of the discharge circuit 4, and (e) The voltage of the capacitor C1 is shown, and (f) shows the relationship between the input current and the discharge current of the capacitor C1.

  When the switching load device is turned on and off as shown in FIG. 3B, the boost converter is turned on and off as shown in FIG. 3C. When the capacitor is charged, a current flows to the three-phase AC power supply (distribution line) side as shown in FIG. When the switching load device is turned off, the discharge circuit is turned on, the capacitor C1 is discharged, and the terminal voltage of the capacitor C1 changes as shown in (e).

  As shown in FIG. 3F, the charging / discharging current of the capacitor C1 depends on the relationship between the on-operation period Ton of the switching load device and the cycle T of the on / off operation. When the value is Imax, the averaged input current Iin is Iin = (Ton / T) Imax according to the embodiment of the present invention. The discharge current Ic of the capacitor C1 is Ic = (1−Ton / T) Imax. Therefore, if the capacitance of the capacitor C1 is selected according to the relationship between the operation on period Ton and the operation off period T-Ton of the switching load device, control is performed so that the input current from the AC power supply (distribution line) hardly changes. Therefore, the voltage fluctuation of the AC power supply (distribution line) can be suppressed almost completely. Thereby, it is possible to prevent the occurrence of flicker in the lighting equipment connected to the AC power supply (distribution line).

  FIG. 4 is an explanatory diagram of Embodiment 2 of the present invention. The same reference numerals as those in FIG. 1 denote the same parts, 21 is a flip-flop, 22 is a comparator, 23 is a clock generator, 24 is a drive circuit, and 25 is a reference. Voltage, 26 is a current detector, 27 is a PWM controller, 28 is an error amplifier, and Q3 is a transistor.

  The power supply device 1 has a configuration including a rectifier circuit 2, a boost converter 3, a discharge circuit 4, a converter 5, and a capacitor C1, and based on on / off information of the operation of the switching load device 6, The ON / OFF control unit 7 controls the on / off operation of the boost converter 3 and the off / on operation of the discharge circuit 4.

  The boost converter 3 detects the current flowing through the transistor Q1 by the current detection unit 8, compares the detection signal with the reference voltage 9 by the comparator 22, inputs the comparison output signal to the reset terminal R of the flip-flop 21, and outputs the clock. The clock signal from the generator 23 is input to the set terminal S, and the output signal from the output terminal Q is input to the drive circuit 12. That is, a case where a configuration of a pulse-by-pulse control circuit is shown is shown. The boost converter 3 charges the capacitor C1 as a load of the rectifier circuit 2 during the operation-off period of the switching load device 6, and a current from the three-phase AC power supply (distribution line) side flows correspondingly.

  The discharge circuit 4 detects the discharge current by the current detection unit 26 during the operation on period of the switching load device 6, compares the reference voltage 25 with the error amplifier 28, and inputs the error component to the PWM control unit 27. The PWM control unit 27 controls the drive circuit 24 to control the pulse width of the transistor Q3, and discharges the charge of the capacitor C1 to the converter 5 side.

  Therefore, the current of the AC power supply (distribution line) during the operation on period of the switching load device 6 and the current of the AC power supply (distribution line) during the operation off period can be made substantially the same. It is possible to suppress voltage fluctuation of the AC power supply (distribution line) and prevent flickering of the lighting equipment.

It is explanatory drawing of Example 1 of this invention. It is explanatory drawing of a voltage fluctuation. It is explanatory drawing of operation | movement of each part, an electric current, and a voltage. It is explanatory drawing of Example 2 of this invention. It is explanatory drawing of the voltage fluctuation of a distribution line.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Power supply device 2 Rectifier circuit 3 Boost converter 4 Discharge circuit 5 Converter 6 Switching load apparatus 7 ON / OFF control part 8 Current detection part 9 Reference voltage 10 Error amplifier 11 PWM control part 12 Drive circuit 13 Reference voltage 14 Comparator 15, 16 Resistor C1, C2 Capacitor Q1, Q2 Transistor D1 Diode

Claims (3)

  A rectifier circuit that rectifies an AC voltage, a converter that supplies the rectified output voltage of the rectifier circuit to a switching load device, and boosts the rectified output voltage of the rectifier circuit to charge a capacitor during an operation-off period of the switching load device. A power supply apparatus comprising: a boost converter; and a discharge circuit that discharges the charge of the capacitor to the converter side during an operation-on period of the switching load device.   The boost converter performs the charging operation of the capacitor according to information on the operation off of the switching load device, stops the charging operation of the capacitor based on the operation on information of the switching load device, and the discharge circuit includes the switching load. 2. The control unit according to claim 1, further comprising: a controller that performs a discharge operation of the capacitor based on information about an operation on the device, and performs a control to stop the discharge operation of the capacitor based on the information about an operation off of the switching load device. Power supply.   2. The power supply apparatus according to claim 1, wherein the discharge circuit includes a configuration in which a discharge current of the capacitor is detected to control a transistor, and constant current discharge is performed by the transistor.

Images