JP2006136113A - Power supply - Google Patents

Abstract

The present invention expands the conduction angle of an input current by simple control, supports IEC harmonic regulation, improves the power factor, and obtains a large output.
Rectification circuits 3a to 3d for rectifying an AC power supply voltage 1 to output a pulsating voltage, a reactor 2 connected to the rectification circuits 3a to 3d, and a semiconductor switch are connected to and disconnected from a current path. Between the switching means 8, the power factor improving capacitor 5 connected in series with the switching means 8 and connected between the AC input terminals and DC output terminals of the rectifier circuits 3 a to 3 d, and the AC input terminals of the rectifier circuits 3 a to 3 d And a smoothing capacitor 4 that smoothes the output voltage of the power factor correction circuit and obtains a substantially DC voltage.
[Selection] Figure 1

Description

  The present invention relates to a power supply device for converting AC to DC and reducing a harmonic component of an input current to improve a power factor.

  Capacitor input type rectifier circuits have been used in various fields as an AC-DC converter circuit in which AC voltage is input to a diode rectifier circuit to obtain a pulsating output, and this is smoothed by a capacitor to obtain a DC voltage. ing. The input current of this circuit has a narrow current conduction angle, a poor power factor, and a large amount of reactive power, so that the power cannot be effectively used, and it contains many harmonic components and is an obstacle to equipment connected to the same power supply system. Is a problem.

  Therefore, a power supply device shown in Patent Document 1 has been studied as a technique for improving the power factor and reducing harmonic components. FIG. 8 is a circuit configuration diagram of the power supply device. The power supply device of FIG. 8 includes an AC input terminal and a DC output terminal of the rectifier circuits 73a to 73d, in addition to a capacitor input circuit composed of an AC power supply 71, a reactor 72, diodes 73a to 73d and a smoothing capacitor 74. A power factor improving capacitor 75 is inserted between them. Reference numeral 80 denotes a load such as a motor drive inverter.

  FIG. 9 shows an example of voltage / current waveforms of the power supply device of FIG. Hereinafter, the operation will be described in detail by dividing one cycle of the AC power supply 71 into four periods with reference to FIG.

  Period 1: There is no charging voltage in the power factor improving capacitor 75, and the AC power source 71 starts to output a positive voltage from zero and, as shown in FIG. 10A, the AC power source 71, the reactor 72, and the power factor improving capacitor 75. The current Iin for charging the voltage Vc of the power factor improving capacitor 75 flows in the order of the diode 73d and the AC power supply 71.

  This operation continues until the power factor improving capacitor 75 is charged and the voltage Vc across the power factor improving capacitor becomes equal to the voltage Vdc across the smoothing capacitor.

  Period 2: Since the voltage value Vac of the AC power supply 71 becomes larger than the voltage Vdc across the smoothing capacitor, as shown in FIG. 10B, the AC power supply 71, the reactor 72, the diode 73a, the smoothing capacitor 74, the diode 73d, and the AC power supply A current Iin for charging the voltage Vdc of the smoothing capacitor 74 flows in the order of 71.

  In addition, current continues to flow through the path of FIG. 10B until the energy stored in the reactor 72 is released in the periods 1 and 2.

  Period 3: The power factor improving capacitor 75 is charged with the same voltage Vc as the voltage Vdc across the smoothing capacitor, and the AC power supply 71 starts to output a negative voltage from zero, and as shown in FIG. A current Iin for discharging the voltage Vc of the power factor improving capacitor 75 flows in the order of the power source 71, the diode 73c, the smoothing capacitor 74, the power factor improving capacitor 75, the reactor 72, and the AC power source 71.

  This operation continues until the voltage Vc charged in the power factor correction capacitor 75 is discharged to zero.

Period 4: Since the voltage value Vac of the AC power supply 71 is larger than the voltage Vdc across the smoothing capacitor, as shown in FIG. 10D, the AC power supply 71, the diode 73c, the smoothing capacitor 74, the diode 73b, the reactor 72, the AC power supply A current Iin for charging the voltage Vdc of the smoothing capacitor 74 flows in the order of 71.

  In addition, current continues to flow through the path of FIG. 10D until the energy stored in the reactor 72 is released in the periods 3 and 4.

  As described above, the current conduction angle is widened by repeating the operations of the periods 1 to 4 for each period of the AC power supply 71, so that the power factor can be improved and the harmonic component contained in the input current Iin can be reduced. it can.

In addition, since the energy stored in the reactor 72 in periods 1 and 3 is released in periods 2 and 4, respectively, the output voltage of the power supply device, that is, the voltage Vdc of the smoothing capacitor 74 can be increased.
Japanese Patent No. 3377959

  However, although the conventional power supply apparatus shown in FIG. 8 can improve the power factor with a simple configuration, it is necessary to set a large value for the reactor 72 in order to comply with the IEC harmonic regulation. As the load increases, the phase of the current Iin with respect to the voltage value Vac of the AC power supply 71 is delayed, and the power factor decreases, so that there is a problem that the power that can be supplied to the load 80 decreases.

  Further, since the voltage drop due to the reactor 72 is large and the output voltage, that is, the voltage across the smoothing capacitor 74 is lowered, there is a problem that a necessary voltage cannot be obtained as the load 80 increases.

  The present invention solves such a conventional problem, and an object of the present invention is to provide a power supply apparatus that can comply with IEC high frequency regulations and can realize a high power factor and a high output.

  In order to solve the above problems, the present invention provides a rectifier circuit that rectifies an AC power supply voltage and outputs a pulsating voltage, a reactor connected to the rectifier circuit, and a connection between the AC input terminal and the DC output terminal of the rectifier circuit. A power factor improving capacitor, a phase improving capacitor connected between the AC input terminals of the rectifier circuit, and a smoothing capacitor for smoothing the output voltage of the power factor improving circuit to obtain a substantially DC voltage. .

  With the above-described configuration, the power factor and the output voltage can be significantly improved, and a power supply device that can meet the IEC harmonic regulations with a simple and inexpensive configuration and can realize a high output can be provided.

  The power supply device of the present invention can achieve high power factor and high output while clearing IEC harmonic regulations.

The first invention comprises a rectifier circuit that rectifies an AC power supply voltage and outputs a pulsating voltage, a reactor, an open / close unit that connects and disconnects a current path, and a semiconductor switch that is connected in series with the open / close unit and rectified. The power factor improving capacitor connected between the AC input terminal and DC output terminal of the circuit, the phase improving capacitor connected between the AC input terminal of the rectifier circuit, and the output voltage of the power factor improving circuit are smoothed and substantially And a smoothing capacitor for obtaining a DC voltage.

  Thereby, since a power factor and an output voltage can be improved significantly, there exists an effect that the power supply device which can drive a big load while responding to IEC harmonic regulation is produced.

  Further, since the power factor and the output voltage can be improved by a simple configuration and control, there is an effect that it is possible to provide a power supply device that generates less noise and has extremely high reliability.

  The second invention further comprises a zero cross detection means for detecting a zero cross of the power supply voltage and outputting a zero cross detection signal, and a switch control means for controlling the opening / closing means, wherein the switch control means receives the zero cross signal detected by the zero cross detection means. In response to this, a pulse signal for turning on the opening / closing means is output.

  Thereby, since a high power factor and an output voltage can be reliably obtained with a simple configuration, there is an effect that reliability can be improved with a high power factor.

  The third aspect of the present invention further includes load state detection means for detecting the magnitude of the load, and the switch control means is configured such that the period during which the switching means is turned on changes according to the magnitude of the load detected by the load state detection means. A pulse signal is output.

  Thereby, since a very high power factor and output voltage can be obtained with a simple configuration, there is an effect that it is possible to cope with a load having a high current utilization factor and a large fluctuation range.

  A fourth invention is an air conditioner using the power supply device of any one of the first to third inventions. According to the air conditioner of the present invention, the current utilization rate is high and high performance is exhibited. There is an effect that can be.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a circuit configuration diagram of a power supply device according to Embodiment 1 of the present invention. In FIG. 1, 1 is an AC power source, 2 is a reactor for improving the power factor, and 3a to 3d are rectifying elements, which rectify the AC voltage and output a pulsating voltage. 4 is a smoothing capacitor for smoothing the pulsating voltage rectified by the rectifying elements 3a to 3d to obtain a substantially DC voltage, 5 is a power factor improving capacitor for improving the power factor together with the reactor 2, and 6 is for improving the current phase. This is a phase improving capacitor.

  Reference numeral 8 denotes a switch device connected in series with the power factor improving capacitor 5, which is composed of a semiconductor switch such as an IGBT or a power MOSFET. Reference numeral 10 denotes a load of the power supply device, which includes a heating wire, an inverter, and a lighting device or a motor that is connected to the inverter and operates. A switch control device 30 controls the switch device 8.

  FIG. 2 is a main waveform diagram in the power supply device of the present invention, where Vac is a voltage waveform of the AC power source 1, Iin is a current waveform flowing through the reactor 2, Vc1 is a voltage waveform across the power factor improving capacitor 5, and Vc2 is A voltage waveform at both ends of the phase improving capacitor 6, Vdc indicates a voltage waveform at both ends of the smoothing capacitor 4, and Psw 1 indicates a pulse signal for driving the first switch 8.

  3 is a current conduction path diagram showing paths through which current flows in each period of the waveform diagram shown in FIG. Hereinafter, the operation in each period will be described in detail with reference to FIGS. 1 to 3.

  Period 1: The voltage Vc1 of the power factor improving capacitor 5 is discharged to some extent during the immediately preceding negative half cycle, and the voltage Vc2 of the phase improving capacitor 6 is charged to approximately -Vdc. The AC power source 1 starts to output a positive voltage from zero, and the voltage Vc2 of the phase improving capacitor 6 is discharged in the order of the AC power source 1, the reactor 2, the phase improving capacitor 6, and the AC power source 1 as shown in FIG. Current Iin flows.

  This operation continues until the voltage Vc2 charged in the phase improving capacitor 6 is discharged to zero and then charged until it reaches the same value as the voltage Vc1 of the power factor improving capacitor 5.

  Period 2: both the power factor improving capacitor 5 and the phase improving capacitor 6 increase the voltage Vac of the AC power source 1 and the AC power source 1, the reactor 2, the power factor improving capacitor 5, and the diode 3d as shown in FIG. In this order, the voltage Vc1 of the power factor improving capacitor 5 is charged in the order of the AC power source 1, and the voltage Vc2 of the phase improving capacitor 6 is charged in the order of the AC power source 1, the reactor 2, the phase improving capacitor 6, and the AC power source 1. A current flows and Iin is the sum of these two currents.

  This operation is continued while the switch device 8 is in the on state. When the switch device 8 is in the off state, the power factor improving capacitor 5 is not charged, and the phase improving capacitor passes through the current path of FIG. Only 6 is charged.

  Period 3: the power supply voltage Vac becomes higher than the voltage Vdc of the smoothing capacitor 4, and the AC power source 1, the reactor 2, the diode 3a, the smoothing capacitor 4, the diode 3d, and the AC power source 1 are smoothed in this order as shown in FIG. A current Iin for charging the voltage Vdc of the capacitor 4 flows.

  Period 4: The power factor improving capacitor 5 does not flow because the switch device 8 is in the off state. In addition, since the voltage of the phase improving capacitor 6 is both charged to approximately Vdc, no current flows. During this period, the energy stored in the reactor 2 in the periods 1, 2, and 3 is released, and as shown in FIG. 3C, the AC power source 1, the reactor 2, the diode 3a, the smoothing capacitor 4, the diode 3d, and the AC power source A current Iin for charging the voltage Vdc of the smoothing capacitor 4 flows in the order of 1.

  Period 5: The voltages of the power factor improving capacitor 5 and the phase improving capacitor 6 are both charged to approximately Vdc. In this period, first, as shown in FIG. 3 (d), the AC power source 1, the phase improving capacitor 6, A current Iin for discharging the electric charge of the phase improving capacitor 6 flows in the order of the reactor 2 and the AC power supply 1.

  This operation continues until the voltage Vc2 charged in the phase improving capacitor 6 is discharged to zero.

  Period 6: The voltage Vc2 of the phase improving capacitor 6 is discharged to zero, but the voltage Vc1 of the power factor improving capacitor 5 remains charged in a positive half cycle, as shown in FIG. As shown, the AC power source 1, the phase improving capacitor 6, the reactor 2, the current for charging the phase improving capacitor in this order, the AC power source 1, the diode 3c, the smoothing capacitor 4, the power factor improving capacitor 5, and the reactor 2. A current for discharging the power factor correction capacitor 5 flows in the order of the AC power source 1, and Iin is the sum of these two currents.

  This operation is continued while the switch device 8 is in the on state. When the switch device 8 is in the off state, there is no discharge from the power factor improving capacitor 5, and the phase improving capacitor passes through the current path of FIG. Only 6 is charged.

  Period 7: The power supply voltage Vac becomes higher than the voltage Vdc of the smoothing capacitor 4, and the AC power supply 1, reactor 2, diode 3a, smoothing capacitor 4, diode 3d, and AC power supply 1 are smoothed in this order as shown in FIG. A current Iin for charging the voltage Vdc of the capacitor 4 flows.

  Period 8: No power flows through the power factor improving capacitor 5 because the switch device 8 is in the off state. Further, since the voltages of the phase improving capacitor 6 are both charged to approximately -Vdc, no current flows. In this period, the energy stored in the reactor 2 in the periods 5, 6 and 7 is released, and as shown in FIG. 3 (f), the AC power source 1, the diode 3c, the smoothing capacitor 4, the diode 3b, the reactor 2, the AC power source A current Iin for charging the voltage Vdc of the smoothing capacitor 4 flows in the order of 1.

  As described above, by repeating the operations in the periods 1 to 8 for each cycle of the AC power supply 1, the rising of the input current can be accelerated and a current waveform having a wide conduction angle can be obtained. Therefore, the power factor can be improved and the harmonic component contained in the input current Iin can be reduced.

  In particular, as compared with the conventional power supply device shown in FIG. 8, when the voltage Vac of the AC power supply 1 rises from zero, the current Iin can be made to flow quickly by the discharge current of the phase improving capacitor 6, and the power factor is further improved. By flowing the current Iin relatively gently by the charging / discharging current of the capacitor 5 for phase and the capacitor 6 for improving the phase, a substantially sinusoidal current waveform can be realized as a whole. Thereby, a very high power factor is realizable compared with the past.

  Further, compared with the power supply device shown in FIG. 8, the amount of increase in energy storage in the reactor 2 in the periods 1 and 4 in FIG. 2, and further in the periods 2 and 5, in addition to the power factor improving capacitor 5 and the phase improving capacitor 6 Since the increase in the energy accumulation in the reactor 2 due to the increase in charging / discharging to is charged in the smoothing capacitor 4 in the periods 3 and 6, a very large output voltage Vdc can be obtained.

  The output voltage Vdc can be changed by changing the time for which the switch device 8 is turned on.

  As a result, if the circuit constant is selected optimally, the IEC harmonic regulation can be cleared and the output can be changed by controlling the on-time of the switch device 8, so that it can cope with loads of various sizes. it can.

  As can be seen from the above description, according to the power supply device of the present invention, a very high power factor and output voltage can be obtained with a simple configuration, and the output voltage can be varied. It is possible to provide a power supply device with a wide range of correspondence.

(Embodiment 2)
FIG. 4 is a circuit configuration diagram of the power supply device according to the second embodiment of the present invention. The same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted. In FIG. 4, reference numeral 31 denotes a zero-cross detection device that detects a zero-cross point of the AC power supply 1, and is constituted by a photocoupler, an insulation transformer, or the like. Hereinafter, the power supply device of the present invention will be described in detail with reference to FIGS.

  When the zero cross detection device 32 detects the zero cross point of the AC power source 1, it outputs a zero cross detection signal to the switch control device 30. When receiving the zero cross detection signal, the switch control device 30 outputs a pulse signal that turns on the switch device 8 for a predetermined time.

  As a result, the switch device 8 can be reliably driven every half cycle of the AC power supply 1 to improve the power factor and control the output voltage.

  As can be seen from the above description, according to the power supply device of the present invention, a high power factor and an output voltage can be reliably obtained with a simple configuration. Can do.

(Embodiment 3)
FIG. 5 is a circuit configuration diagram of a power supply device according to Embodiment 3 of the present invention. The same components as those in FIGS. 1 and 4 are denoted by the same reference numerals, and detailed description thereof is omitted. In FIG. 5, 20 is a load current detection device that detects the value of the current flowing through the load 10, and 21 is an output voltage detection device that detects the voltage Vdc across the smoothing capacitor 4. In addition, both the load current detection device 20 and the output voltage detection device 21 output the detected value to the switch control device 30. Hereinafter, the power supply device of the present invention will be described in detail with reference to FIGS.

  When the load 10 is an inverter and a motor driven at a variable speed by the inverter, the size of the load 10 changes depending on the rotational speed of the motor and the like. Therefore, it is desirable that the power supply device secures a power factor necessary for suppressing harmonics and an output voltage (Vdc) necessary for driving the load 10 in the fluctuation range of the load 10.

  The control device 30 can calculate the size of the load 10 by detecting the voltage Vdc across the smoothing capacitor 4 from the output voltage detection device 21 and the current flowing through the load 10 from the load current detection device 20.

  The switch control device 30 controls the switch device 8 so as to increase the time for turning on the switch device 8 according to the size of the load 10. In this case, the length of a necessary pulse signal may be stored in advance according to the size of the load 10, or feedback may be performed so that the voltage Vdc of the smoothing capacitor 4 becomes a predetermined value. . FIG. 6 shows an example of a pulse width output from the switch control device 30 to the switch device 8 with respect to the magnitude of the load.

  As a result, if the circuit constant and the ON time of the switch device 8 are set optimally, a high power factor can be obtained in the entire region of the load 10, and a load whose size varies can be dealt with.

As can be seen from the above description, according to the power supply device of the present invention, a very high power factor and output voltage can be obtained with a simple configuration. Therefore, a power supply corresponding to a load having a high current utilization factor and a large fluctuation range. An apparatus can be provided.
The on operation of the switch device 8 described in the present embodiment is an example, and the operation of the power supply device of the present invention is not limited to this.

(Embodiment 4)
FIG. 7 shows a configuration example of an air conditioner to which the power supply device according to Embodiment 1 of the present invention is applied. 7, the same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted. Hereinafter, the air conditioner of the present invention will be described with reference to FIG.

As shown in FIG. 7, the air conditioner uses the power supply device of the invention shown in the first embodiment as a compressor driving device. In addition to the inverter device 81 and the electric compressor 82 as the load 10, the indoor unit 92, A refrigeration cycle comprising an outdoor unit 95 and a four-way valve 91 is provided.

  The indoor unit 92 includes an indoor heat exchanger 93 and an indoor fan 94, and the outdoor unit 95 includes an outdoor heat exchanger 96, an outdoor fan 97, and an expansion valve 98.

  During the refrigeration cycle, a refrigerant that is a heat medium circulates. The refrigerant is compressed by the electric compressor 82, and heat is exchanged with the outdoor air by blowing from the outdoor blower 97 in the outdoor heat exchanger 96, and indoor air is blown from the indoor blower 94 in the indoor heat exchanger 93. And heat exchange. Indoor air conditioning is performed by the air after heat exchange in the indoor heat exchanger 93. Switching between cooling and heating is performed by reversing the direction of refrigerant circulation by a four-way valve 91.

  The circulation of the refrigerant in the refrigeration cycle as described above is performed by driving the electric compressor 82 by the inverter device 81, and the control method of the inverter device 81 and the electric compressor 82 is the power source of the first embodiment. This is done using a device. Since the configuration and operation of the power supply device are as described above, description thereof will be omitted.

  With the configuration as described above, it is possible to suppress deterioration in control performance such as a decrease in efficiency in the air conditioner.

  In the present embodiment, the air conditioner using the power supply device of the invention shown in the first embodiment as the compressor driving device has been described, but the power supply device of another invention as shown in the second or third embodiment. Even if it uses, the air conditioner which had the effect which the power supply device of each invention has similarly can be provided.

  Therefore, the effect of the power supply apparatus according to the present invention can be fully utilized by using it particularly for an air conditioner with a large load change.

  As described above, the power supply device according to the present invention can realize a high power factor and a high output, and therefore can be applied to uses such as an outdoor unit of an air conditioner.

The circuit block diagram of the power supply device in Embodiment 1 of this invention Main voltage / current waveform diagram of power supply device according to Embodiment 1 of the present invention (A)-(f) Current path figure of power supply device in Embodiment 1 of this invention The circuit block diagram of the power supply device in Embodiment 2 of this invention The circuit block diagram of the power supply device in Embodiment 3 of this invention The figure which shows the magnitude | size of the load of the power supply device of this invention with respect to the pulse width of a switch drive signal Configuration of the air conditioner of the present invention Circuit diagram of conventional power supply Main voltage / current waveform diagram of conventional power supply (A)-(d) Current path diagram of conventional power supply device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 AC power supply 2 Reactor 3a, 3b, 3c, 3d Rectifier 4 Smoothing capacitor 5 Power factor improvement capacitor 6 Phase improvement capacitor 8 Switch device 10 Load 20 Load current detection device 21 Output voltage detection device 30 Control device 31 Zero cross detection device

Claims (4)

A rectifier circuit that rectifies an AC power supply voltage and outputs a pulsating voltage, a reactor connected in series to one line of the AC input of the rectifier circuit, and a power factor improving capacitor connected in series. Opening / closing means for connecting / cutting off a current path connected between the AC input terminal and the negative DC output terminal, a phase improving capacitor connected between the AC input terminals of the rectifier circuit, and the power factor improving circuit And a smoothing capacitor that obtains a substantially DC voltage by smoothing the output voltage, wherein the switching means is constituted by a semiconductor switch. Zero cross detection means for detecting a zero cross of a power supply voltage and outputting a zero cross detection signal, and switch control means for controlling the opening / closing means, the switch control means receiving the zero cross signal detected by the zero cross detection means for the opening / closing. 2. The power supply device according to claim 1, wherein a pulse signal for turning on the means is output. Load condition detection means for detecting the magnitude of the load is further provided, and the switch control means outputs a pulse signal so that the period during which the opening / closing means is turned on changes according to the load magnitude detected by the load condition detection means in the previous period. The power supply device according to claim 2, wherein: An air conditioner comprising the power supply device according to any one of claims 1 to 3.

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