JP2005102489A - Power supply device and air conditioner using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply device capable of stable operations, without being affected by the fluctuations in the AC power supply voltage, and provide an air conditioner. <P>SOLUTION: The power supply device is provided with an AC power supply voltage detecting part (41) for detecting the voltage of the AC power supply (1); a zero-cross detection part (21), which detects the zero-cross point of the AC power supply voltage, on the basis of the detected voltage of the AC power supply and outputs a zero-cross detecting signal; a pulse signal control part (22) which generates and outputs a pulse signal for turning on/off switching elements (4a, 4b) of a power factor improving circuit (7), on the basis of the zero-cross detecting signal; and a switch driving part (23) which drives each switching element of the power factor improving circuit (7) by receiving the pulse signal. The zero-cross detecting part includes a timer (21a), which outputs the zero-cross detecting signal, after the elapse of a delay time (td) from the time when the AC power supply voltage reaches a prescribed voltage, and a correction part (21b) for correcting the delay time (td), based on the AC power supply voltage. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a power supply device, and more particularly to a power supply device using a DC voltage variable function of a power factor correction circuit. Furthermore, this invention relates to the air conditioner using the power supply device.

  Conventionally, as an AC-DC conversion circuit, a capacitor input type rectifier circuit that obtains a DC voltage by inputting an AC voltage to a diode rectifier circuit to obtain a pulsating current output, and obtaining a DC voltage in various fields. It is used in.

  When a capacitor-input type rectifier circuit is used for a power supply device, the input current has a problem that the current conduction angle is narrowed, the power factor is poor, and the reactive power is large, so that the power cannot be effectively used. In addition, since the input current includes many harmonic components, there is a problem with a failure in equipment connected to the same power supply system. Therefore, there is a power supply device that improves the power factor and reduces harmonic components (see, for example, Patent Document 1).

  This power supply apparatus has a circuit configuration as shown in FIG. The power supply device shown in FIG. 8 has a circuit configuration in which an AC voltage Vin input from the AC power supply 101 is converted into a pulsating output voltage by a rectifier circuit 103, and a reactor 102 is inserted into this circuit configuration. The reactor 102 can mitigate the inrush of the input current Iin. As a result, the current conduction angle is widened, the power factor can be improved, and the harmonic component contained in the input current Iin can be reduced.

  For example, when this power supply device is used in an air-conditioner, the load 105 is a compressor motor and an inverter that drives the motor. When the AC power supply 101 is 100 V, this power supply device normally operates as a voltage doubler rectifier circuit with the relay circuit 130 in a conductive state, and also in a low load region by shutting off the relay circuit 130. By operating as a full-wave rectifier circuit, the output DC voltage can be kept low. At this time, loss in the inverter and motor can be reduced.

  As described above, the conventional power supply device shown in FIG. 8 can improve the power factor by inserting only a passive element (reactor) having a simple configuration, and can switch the load 105 by switching the energization state of the relay circuit 130. Loss can be suppressed.

  As another example, there is a power supply device having a circuit configuration shown in FIG. 9 (see Patent Document 2). The detailed operation of this power supply apparatus will be described below.

  In FIG. 9, the rectifier circuit 133 and the switching element 131 constitute a power factor correction circuit. The control unit 132 outputs a pulse signal that turns on the switching element 131 for a predetermined time in synchronization with the zero cross point of the AC power supply 101. As a result, a current for short-circuiting the AC power supply 101 flows through the rectifier circuit 133 and the switching element 131 via the reactor 102, and thus the input current starts to flow from the zero cross point of the AC power supply 101. When the switching element 131 is turned off, current flows through the reactor 102, the rectifier circuit 103, and the capacitors 120a and 120b or the smoothing capacitor 104. As a result, the current conduction angle can be greatly increased, and the power factor can be greatly improved.

  When this power supply apparatus is also used in an air conditioner, the load 105 is a compressor motor and an inverter that drives the motor. Therefore, similarly, by setting the relay circuit 130 in the cut-off state in the low load region, a full-wave rectifier circuit is formed, and the loss in the inverter and the motor can be suppressed.

  As described above, the conventional power supply device shown in FIG. 9 can greatly improve the power factor by a simple configuration and control, and can suppress the loss of the load 105 by switching the energization state of the relay circuit 130. .

Japanese Patent Laid-Open No. 9-182457 JP-A-11-206130

  In the power supply circuit having the configuration shown in FIG. 9, it is determined that the zero cross point has been reached when a state where the input voltage value of the AC power supply Vin is equal to or lower than the predetermined voltage is detected, and the power factor improving circuit is reached after a predetermined time has elapsed from the zero cross point. A pulse signal for turning on the switching element 131 for a predetermined time is output.

  However, in this method, when the input voltage Vin from the AC power source fluctuates, the zero cross detection point also shifts, and the switching element 131 cannot be turned on at the correct timing, leading to a decrease in efficiency of the power factor correction circuit. It was.

  Also, the output voltage value of the power factor correction circuit decreases due to fluctuations in the input power supply voltage Vin or an increase in load. Therefore, the set value of the output voltage of the power factor correction circuit is set to a maximum possible value so as not to be affected even if the output voltage is lowered due to power supply voltage fluctuation or load fluctuation. The pulse signal output time during which the switching element of the power factor correction circuit is turned on is set to the maximum value. However, if the maximum value of the pulse signal output time during which the switching element of the power factor correction circuit is turned on is set large, there is a problem that overcurrent flows in the power factor correction circuit. On the other hand, if the maximum value of the pulse signal output time (on time) is set small to avoid overcurrent, the DC output voltage of the power factor correction circuit will not be sufficiently boosted when the input voltage of the AC power supply decreases, The efficiency of the power supply device was reduced.

  The present invention solves such a conventional problem, and an object thereof is to provide a power supply device that enables stable output without being subjected to fluctuations in the AC power supply voltage, and an air conditioner using the power supply device. To do.

  A first power supply device according to the present invention includes a rectifier circuit that rectifies a voltage input from an AC power supply, a reactor connected to the rectifier circuit, a DC voltage rectified by the rectifier circuit, and an input voltage of the AC power supply. A power factor correction circuit for matching the waveform and the input current waveform. The power factor improving circuit is composed of a plurality of switching elements connected in series, switching means for turning on and off the current path of the input current flowing from the AC power supply, a capacitor circuit consisting of a plurality of capacitors connected in series, A backflow preventing rectifying element for preventing the charge charged in the capacitor from flowing back to the switching means when the switching means is in an on state; and a changeover switch means for switching the energized state of the current path to the conductive or interrupted state. The switching means and the capacitor circuit are arranged in parallel, a connection point between the switching elements and a connection point between the capacitors are connected, and an end point of the switching means and an end point of the capacitor circuit are connected via a backflow preventing rectifier element. One end of the changeover switch means is connected to one of the AC connection points of the rectifier circuit, and the other end is connected to a connection point between the switching elements of the power factor correction circuit.

  Further, the first power supply device detects an AC power supply voltage detecting means for detecting the voltage of the AC power supply, and detects a zero cross point of the AC power supply voltage based on the detected voltage of the AC power supply, and outputs a zero cross detection signal. Zero cross detection means, pulse signal control means for generating and outputting a pulse signal for turning on / off each switching element of the power factor improvement circuit based on the zero cross detection signal, and each switching element of the power factor improvement circuit upon receiving the pulse signal Switch driving means for driving. The zero-cross detection means includes a timer means for outputting a zero-cross detection signal after a predetermined delay time (td) from the time when the AC power supply voltage reaches a predetermined voltage, and the voltage value of the AC power supply detected by the AC power supply voltage detection means. Correction means for correcting the delay time (td) based on

  The first power supply device may further include DC detection means for detecting an output voltage of the power supply device. At this time, the pulse signal control means may change the ON time (tw) of the switching element of the power factor improvement means according to the change of the voltage value detected by the DC voltage detection means. Furthermore, the pulse signal control means may change the maximum value of the ON time (tw) of the switching element based on the value of the AC power supply voltage.

  A second power supply device according to the present invention boosts a rectifier circuit that rectifies a voltage input from an AC power source, a reactor connected to the rectifier circuit, and a DC voltage rectified by the rectifier circuit, and inputs the AC power source. A power factor correction circuit for matching the voltage waveform and the input current waveform. The power factor correction circuit is composed of a plurality of switching elements connected in series, switching means for turning on and off the current path of the input current flowing from the AC power supply, a capacitor circuit consisting of a plurality of capacitors connected in series, and switching And a backflow preventing rectifying element for preventing the charge charged in the capacitor from flowing back to the switching means when the means is in the on state, and a changeover switch means for switching the energized state of the current path to the conductive state or the interrupted state. The switching means and the capacitor circuit are arranged in parallel. A connection point between the switching elements and a connection point between the capacitors are connected. An end point of the switching means and an end point of the capacitor circuit are connected via a backflow preventing rectifier element. One end of the changeover switch means is connected to one point of an AC connection point of the rectifier circuit, and the other end is a power factor correction circuit. Are connected to connection points between the switching elements.

  Further, the second power supply device detects the DC power supply voltage detecting means for detecting the DC power supply voltage output from the rectifier circuit, and detects the zero cross point of the AC power supply voltage based on the detected DC power supply voltage. A zero cross detection means for outputting a signal, a pulse signal control means for generating and outputting a pulse signal for turning on and off each switching element of the power factor correction circuit based on the zero cross detection signal, and a power factor improvement circuit for receiving the pulse signal. Switch driving means for driving each switching element. The zero cross detection means is based on a timer means for outputting a zero cross detection signal after a lapse of a predetermined delay time (td) from the time when the DC power supply voltage reaches a predetermined voltage, and the DC power supply voltage detected by the DC power supply voltage detection means. Correction means for correcting the delay time (td).

  The second power supply device may further include DC detection means for detecting the output voltage of the power supply device. The pulse signal control means may change the ON time (tw) of the switching element of the power factor improvement means according to the change of the voltage value detected by the DC voltage detection means. Further, the pulse signal control means may change the maximum value of the ON time (tw) of the switching element based on the value of the DC power supply voltage.

  The air conditioner according to the present invention includes the power supply device described above as a power source.

  According to the present invention, the input voltage from the AC power supply (AC power supply voltage) or the output voltage of the rectifier circuit (DC power supply voltage) is detected, and the zero-cross detection delay time td is corrected based on the detected value, whereby the AC Even if the input voltage of the power supply fluctuates, the zero cross point can be detected with high accuracy. According to this configuration, even if the input voltage of the AC power supply fluctuates, the power factor is improved because fluctuations in the output DC voltage of the power factor correction circuit are suppressed.

  Alternatively, an AC power supply voltage or a DC power supply voltage may be detected, and the maximum value of the on-time (tw) of the switching element of the power factor correction circuit may be corrected based on this voltage. Thereby, the fluctuation | variation of the output voltage by the fluctuation | variation of the input voltage from AC power supply can be suppressed. Therefore, even if the voltage of the AC power supply fluctuates, it is possible to suppress the fluctuation of the output voltage of the power factor correction circuit and improve the power factor.

  In addition, according to the present invention, a highly efficient air conditioner can be realized even if the input voltage of the AC power supply fluctuates.

  Embodiments of a power supply apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. In all the drawings, the same reference numerals indicate the same or equivalent components or parts.

(Embodiment 1)
FIG. 1 is a circuit configuration diagram of a power supply device according to a first embodiment of the present invention.

  The power supply device includes a rectifier circuit 2, a reactor 3, a power factor circuit 7, a smoothing capacitor 8, and a changeover switch 12.

  The rectifier circuit 2 includes a plurality of rectifier elements 2a, 2b, 2c, and 2d, rectifies the AC voltage Vin from the AC power supply 1, and outputs a pulsating voltage. The reactor 3 is inserted to improve the power factor.

  The power factor correction circuit 7 includes two switching elements 4a and 4b, two capacitors 5a and 5b, two backflow prevention rectifying elements 6a and 6b, and a changeover switch 12. The smoothing capacitor 8 smoothes the output voltage of the power factor correction circuit 7. A load 9 is connected to the power supply device.

  The changeover switch 12 is connected between the connection point of the rectifying elements 2 b and 2 d of the rectifier circuit 2 and the connection point of the switching elements 4 a and 4 b of the power factor correction circuit 7. The change-over switch 12 is turned on / off to switch the conduction state of the current path between these connection points to conduction or interruption. The changeover switch 12 includes a relay circuit that is a mechanical switch, a semiconductor element that is an electrical switch, and the like. The power supply device performs a power factor improving operation based on a voltage doubler rectifier circuit when the changeover switch 12 is turned on, and performs a power factor improving operation based on a full wave rectifier circuit when the changeover switch 12 is turned off. Do.

  In the power factor correction circuit 7, the midpoint of the series connection of the two switching elements 4a and 4b and the midpoint of the series connection of the two capacitors 5a and 5b are connected to each other. The switching element 4a and the capacitor 5a are connected via a backflow preventing rectifying element 6a. The switching element 4b and the capacitor 5b are connected via a backflow preventing rectifying element 6b.

  For the switching elements 4a and 4b, a self-extinguishing semiconductor such as a power transistor, a power MOSFET, or an IGBT is used. Specific examples of the load 9 include a heating wire, an inverter, and a lighting device and a motor that are connected to the inverter and operate.

  Furthermore, the power supply device includes a zero cross detection unit 21, a pulse signal control unit 22, a switch drive unit 23, a changeover switch drive unit 24, and an AC power supply voltage detection unit 41 as components of the control system.

  The AC power supply voltage detection unit 41 detects the power supply voltage Vin of the AC power supply 1.

  The zero cross detection unit 21 detects the zero cross point of the AC power source 1 based on the signal from the AC power source voltage detection unit 41 and outputs a zero cross detection signal. Details of the zero-cross point detection operation of the zero-cross detector 21 will be described later.

  The pulse signal control unit 22 receives the zero cross detection signal from the zero cross detection unit 21 and generates and outputs a pulse signal for driving the switching elements 4a and 4b. The pulse signal control unit 22 is configured by a general-purpose logic circuit or a microcomputer. The switch driving unit 23 receives the pulse signal from the pulse signal control unit 22 and turns on / off the switching elements 4a and 4b. The changeover switch drive unit 24 drives the changeover switch 12.

  FIG. 2 shows waveforms of the power supply voltage, input current, and pulse signal in the power supply device of this embodiment. The symbol “Vin” in the figure is the voltage waveform of the AC power supply 1 and “Iin” is the input current waveform, and the direction of the arrow is the positive direction. “Pa” indicates a pulse signal for driving the switching element 4a, and “Pb” indicates a pulse signal for driving the switching element 4b. “Va” and “Vb” indicate the voltage across the capacitors 5a and 5b, respectively. “Vdc” indicates the voltage across the smoothing capacitor 8, that is, the output voltage of the power supply device.

  The pulse signal control unit 22 is a pulse that turns on at least one of the switching elements 4a and 4b for a certain time (tw) in synchronization with the zero cross point of the voltage Vin of the AC power supply 1 detected by the zero cross detection unit 21. Output a signal. In the example of FIG. 2, the switching element 4a is turned on for a certain time (tw) in the positive half cycle of the AC power supply 1, and the switching element 4b is turned on for a certain time (tw) in the negative half cycle. Yes. Although not shown, the changeover switch 12 is turned on in synchronization with the on periods of the switching elements 4a and 4b, for example.

  In FIG. 2, when the switching element 4a is in the ON state, the voltage on the load 9 side as viewed from the AC power supply 1 is equal to the voltage Vb across the capacitor 5b, so that the input current Iin begins to flow from the point where the voltage Vin exceeds the voltage Vb. , Until the pulse signal Pa is turned off.

  When the pulse signal Pa is turned off, the voltage on the load 9 side viewed from the AC power supply 1 becomes equal to the voltage Vdc across the smoothing capacitor 8. At this time, if the voltage Vin is smaller than the voltage Vdc, the input current Iin once decreases. However, the current for charging the capacitor 8 again flows from the point where the voltage value Vin exceeds the voltage Vdc across the smoothing capacitor 8.

  As a result, the rise of the input current Iin can be accelerated and the current conduction period can be extended. Similarly, in the negative half cycle, when the switching element 4b is in the ON state, the input current Iin flows from the time when the voltage Vin exceeds the voltage Va across the capacitor 5a, so that the current conduction period can be extended.

  By repeating these operations every half cycle of the AC voltage of the AC power supply 1, the current conduction period can be expanded and a sufficiently high power factor can be obtained.

  Next, a detailed operation of the zero cross detection unit 21 will be described.

  The zero-cross detection unit 21 includes a timer 21a that outputs a zero-cross detection signal after a predetermined delay time (td) from the time when the voltage Vin of the AC power supply 1 reaches the predetermined voltage Vth, and a delay time td that is an output of the timer 21a. And a delay time correction unit 21b for correcting.

  The zero cross detection unit 21 receives the detection value of the AC power supply voltage Vin from the AC power supply voltage detection unit 41 and detects the zero cross point of the AC power supply voltage Vin. Specifically, as shown in FIG. 3, the timer 21a of the zero-cross detection unit 21 compares the AC power supply voltage Vin with a predetermined voltage (zero-cross determination voltage) Vth, and the timing when the input voltage Vin reaches the predetermined voltage Vth. t0 is detected, and a zero cross detection signal is output at a timing tz obtained by delaying the timing t0 by the delay time td.

  Here, consider a case where the voltage value Vin fluctuates to drop to the voltage V′in. In this case, the timing at which the variable input voltage V′in reaches the predetermined voltage Vth is t0 ′. Therefore, if the input voltage V′in is delayed by the delay time td, a point deviated from the true zero cross point is detected as the zero cross point. For this reason, since the switching elements 4a and 4b are not turned on / off at the correct timing, the power factor correction circuit 7 does not operate accurately, leading to deterioration of the power factor.

  Therefore, in the present embodiment, the delay time correction unit 21b in the zero-cross detection unit 21 changes the input value of the power supply voltage Vin according to the value of the AC power supply voltage Vin detected by the AC power supply voltage detection unit 41. The delay time td is corrected so that a true zero cross point is detected. That is, the delay time correction unit 21b monitors the amplitude of the power supply voltage Vin and corrects the delay time td according to the fluctuation of the amplitude value. For example, when the amplitude value (peak value) is smaller than the reference value, the delay time td is set to a larger value t′d. More specifically, the delay time correction unit 21b performs correction so that the corrected delay time t′d satisfies the relationship of the following equation.

t′d = td + Δtd
Δtd = ((AC power supply voltage reference value−AC power supply voltage detection value))
/ Detected value of AC power supply voltage) x A x td
Here, A is a predetermined correction coefficient.

  As described above, according to the power supply device of the present embodiment, the delay time td used for the zero cross determination is corrected according to the fluctuation of the voltage Vin of the AC power supply 1, so that it is accurate regardless of the fluctuation of the AC power supply voltage Vin. The zero cross point of the AC power supply voltage can be detected, and the power factor correction circuit 7 can operate with high accuracy.

(Embodiment 2)
FIG. 4 shows a circuit configuration diagram of a second embodiment of the power supply device according to the present invention.

  The power supply device according to the present embodiment is the power supply device according to the first embodiment, and further includes a DC detection unit 25 that detects the output voltage Vdc of the power supply device. Although the output voltage of the smoothing capacitor 8 is detected as the output voltage Vdc, the output voltage of the power factor correction circuit 7 may be detected. Further, the pulse signal control unit 22 includes a maximum on-time correction unit 22a that changes the maximum value of the on-time (tw) of the switching elements 4a and 4b based on the AC power supply voltage Vin.

  Based on the output voltage Vdc, the pulse signal control unit 22 changes the time (tw) for turning on the switching elements 4a and 4b so that a constant output voltage value is obtained.

  In particular, the pulse signal control unit 22 receives the detection value of the AC power supply voltage Vin from the AC power supply voltage detection unit 41. When the AC power supply voltage Vin decreases, the output voltage Vdc also decreases at the same time. Therefore, when the input voltage Vin of the AC power supply 1 decreases, the pulse signal control unit 22 sets the switching elements 4a and 4b so that the output voltage Vdc becomes a constant voltage value in order to suppress the fluctuation of the output voltage Vdc. The turn-on time tw is increased.

  However, if the switching elements 4a and 4b are turned on for a long time, the current flowing through the power factor correction circuit 7 may increase and the circuit may be destroyed. Therefore, the maximum value of the on time tw is set. . The maximum value of the on-time tw is determined based on the rated value of the voltage of the AC power supply 1. When the voltage Vin of the AC power supply 1 decreases, a desired output voltage value cannot be obtained even if the on-time tw is increased to the maximum value.

  Therefore, in the present embodiment, the maximum on-time correction unit 22a of the pulse signal control unit 22 sets the maximum value of the on-time tw when the AC power supply voltage Vin is lower than the reference value (the rated value of the AC power supply voltage Vin). The AC power supply voltage Vin is increased as compared with the case of the rated value.

  On the other hand, when the input voltage Vin of the AC power supply 1 rises, the output voltage Vdc also rises. Therefore, the pulse signal control unit 22 decreases the ON time tw of the switching elements 4a and 4b so that the output voltage Vdc becomes a constant value. At this time, the maximum on-time correcting unit 22a sets the maximum value of the on-time tw to a time shorter than when the AC power supply voltage Vin is the rated value.

  As described above, in the power supply device of the present embodiment, the maximum value of the on-time tw of the switching elements 4a and 4b is changed according to the change in the AC power supply voltage Vin. The value of the voltage Vdc can be held at a constant value.

(Embodiment 3)
FIG. 5 shows a circuit configuration diagram of a third embodiment of the power supply device according to the present invention.

  The power supply device of the present embodiment includes a DC power supply voltage detection unit 51 that detects the output voltage of the rectifier circuit 2 instead of the AC power supply voltage detection unit 41 in the configuration of the power supply device of the first embodiment shown in FIG. . The zero cross detection unit 21 corrects the delay time td according to the voltage value detected by the DC power supply voltage detection unit 51. That is, the timer 21a compares the DC output voltage (DC power supply voltage) output from the rectifier circuit 2 with a predetermined voltage (zero cross determination voltage) Vth, and detects the timing t0 when the DC output voltage reaches the predetermined voltage Vth. The zero cross detection signal is output at a timing tz obtained by delaying the timing t0 by the delay time td. Other functions are the same as those in the first embodiment.

  Since the DC output voltage (DC power supply voltage) output from the rectifier circuit 2 fluctuates in accordance with the fluctuation of the power supply voltage Vin of the AC power supply 1, the power supply apparatus of this embodiment also has the same power supply as in the first embodiment. Even if the voltage value of the voltage Vin fluctuates, the detected zero cross point can be matched with the true zero cross point. Therefore, the zero cross point of the AC power supply voltage Vin can be detected accurately, and the power factor correction circuit 7 can be operated with high accuracy.

(Embodiment 4)
FIG. 6 shows a circuit configuration diagram of a fourth embodiment of the power supply device according to the present invention.

  The power supply apparatus according to the present embodiment is the power supply apparatus according to the third embodiment, and further includes a DC detection unit 25 that detects the output voltage Vdc of the power supply apparatus. Further, the pulse signal control unit 22 includes a maximum on-time correction unit 22a that changes the maximum value of the on-time of the switching elements 4a and 4b based on the AC power supply voltage Vin.

  Based on the output voltage Vdc, the pulse signal control unit 22 changes the time (tw) for turning on the switching elements 4a and 4b so that a constant output voltage value is obtained.

  The pulse signal control unit 22 inputs the detected value of the DC power supply voltage that is the output of the rectifier circuit 2 from the DC power supply voltage detection unit 51. When the DC power supply voltage decreases, the pulse signal control unit 22 turns on the switching elements 4a and 4b so that the output voltage Vdc has a constant voltage value in order to suppress fluctuation (decrease) in the output voltage Vdc. Increase time tw.

  The maximum on-time correcting unit 22a of the pulse signal control unit 22 increases the maximum value of the on-time tw when the DC power supply voltage is lower than the reference value than when the DC power supply voltage is the reference value.

  On the other hand, when the DC power supply voltage rises above the reference value, the output voltage Vdc also rises. For this reason, when the DC power supply voltage rises, the pulse signal control unit 22 decreases the ON time tw of the switching elements 4a and 4b so that the output voltage Vdc becomes a constant value. At that time, the maximum on-time correcting unit 22a sets the maximum value of the on-time tw to a time shorter than when the DC power supply voltage is the reference value.

  As described above, in the power supply device of the present embodiment, the maximum value of the on-time tw of the switching elements 4a and 4b is changed according to the fluctuation of the DC power supply voltage. The value of Vdc can be held at a constant value.

(Embodiment 5)
The structural example of the air conditioner using the power supply device of the said embodiment is demonstrated.

  In FIG. 7, the structural example of the air conditioner using said power supply device is shown. As shown in the figure, the air conditioner uses the power supply device 100 that converts the AC voltage Vin of the AC power supply 1 into a predetermined DC voltage Vdc, and uses the output of the power supply device 100 as a DC power supply to drive the motor 210. The inverter 200 to generate | occur | produce and the refrigerating cycle 300 which air-conditions indoors by exchanging heat between indoor and outdoor air and a refrigerant | coolant are included.

  The power supply device 100 is any of the power supply devices described in the above embodiments.

  The refrigeration cycle 300 includes an electric compressor 310 that compresses refrigerant circulating in the refrigeration cycle, an indoor heat exchange unit 320, and an outdoor heat exchange unit 320.

  The electric compressor 310 is connected to the motor 210 and is driven by the motor 210.

  According to the power supply device of the above embodiment, a sufficiently high power factor can be obtained with a simple configuration and control, and the output voltage Vdc of the power factor correction circuit can be kept constant even if the voltage value of the AC power supply fluctuates. it can. Therefore, by using the output of such a power supply device as a power supply, it is possible to realize an air conditioner that realizes highly efficient and stable operation without being affected by fluctuations in the input voltage of the AC power supply.

  The power supply device according to the present invention enables stable output without being subjected to fluctuations in the input AC power supply voltage, and thus is useful, for example, for household electrical equipment such as an air conditioner.

It is a circuit block diagram of the power supply device of Embodiment 1 of this invention. FIG. 3 is a diagram illustrating a pulse signal and waveforms of main parts in the power supply device according to the first embodiment. It is a figure for demonstrating the detection timing of a zero crossing point. It is a circuit block diagram of the power supply device of Embodiment 2 of this invention. It is a circuit block diagram of the power supply device of Embodiment 3 of this invention. It is a circuit block diagram of the power supply device of Embodiment 4 of this invention. It is a block diagram of the air conditioner (air-conditioner) using the power supply device of this invention. It is a circuit block diagram which shows an example of the conventional power supply device. It is a circuit block diagram which shows the other example of the conventional power supply device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 AC power supply 2 Rectifier circuit 3 Reactor 4a, 4b Switching element 5a, 5b Capacitor 6a, 6b Diode (backflow prevention rectifier)
7 Power Factor Correction Circuit 8 Smoothing Capacitor 9 Load 12 Changeover Switch 21 Zero Cross Detection Unit 21a Timer 21b Delay Time Correction Unit 22 Pulse Signal Control Unit 22a Maximum On Time Correction Unit 23 Switch Drive Unit 24 Changeover Switch Drive Unit 25 DC Detection Unit 41 AC Power supply voltage detector

Claims (5)

a) a rectifier circuit for rectifying a voltage input from an AC power supply;
b) a reactor connected to the rectifier circuit;
c) a power factor correction circuit that boosts the DC voltage rectified by the rectifier circuit and matches the input voltage waveform and the input current waveform of the AC power supply;
The power factor correction circuit comprises a plurality of switching elements connected in series, a switching means for turning on and off a current path of an input current flowing from the AC power supply, and a capacitor circuit composed of a plurality of capacitors connected in series. A backflow preventing rectifying element for preventing the charge charged in the capacitor from flowing back to the switching means when the switching means is in an on state; and a changeover switch means for switching the energized state of the current path to a conductive or interrupted state. The switching means and the capacitor circuit are arranged in parallel, the connection point between the switching elements and the connection point between the capacitors are connected, and the end point of the switching means and the end point of the capacitor circuit are Connected via a rectifying element, the change-over switch means has one end at the end. Is connected to one point of the AC connection point of the flow circuit, also the other end connected to a connection point between the switching elements of the power factor correction circuit,
d) AC power supply voltage detecting means for detecting the voltage of the AC power supply;
e) Zero-cross detection means for detecting a zero-cross point of the AC power supply voltage based on the detected voltage of the AC power supply and outputting a zero-cross detection signal;
The zero cross detection means includes
Timer means for outputting a zero-cross detection signal after a predetermined delay time (td) has elapsed from the time when the AC power supply voltage has reached a predetermined voltage;
Correction means for correcting the delay time (td) based on the voltage value of the AC power supply detected by the AC power supply voltage detection means,
f) Pulse signal control means for generating and outputting a pulse signal for turning on / off each switching element of the power factor correction circuit based on the zero cross detection signal;
g) A power supply apparatus comprising switch drive means for receiving the pulse signal and driving each switching element of the power factor correction circuit.   DC detection means for detecting an output voltage of the power supply device is further provided, and the pulse signal control means is configured to turn on the switching element of the power factor improvement means according to a change in voltage value detected by the DC voltage detection means. 2. The pulse signal control means changes the maximum value of the on-time (tw) of the switching element based on the value of the AC power supply voltage. Power supply. a) a rectifier circuit for rectifying a voltage input from an AC power supply;
b) a reactor connected to the rectifier circuit;
c) a power factor correction circuit that boosts the DC voltage rectified by the rectifier circuit and matches the input voltage waveform and the input current waveform of the AC power supply;
The power factor correction circuit comprises a plurality of switching elements connected in series, a switching means for turning on and off a current path of an input current flowing from the AC power supply, and a capacitor circuit composed of a plurality of capacitors connected in series. A backflow preventing rectifying element for preventing the charge charged in the capacitor from flowing back to the switching means when the switching means is in an on state; and a changeover switch means for switching the energized state of the current path to a conductive or interrupted state. The switching means and the capacitor circuit are arranged in parallel, the connection point between the switching elements and the connection point between the capacitors are connected, and the end point of the switching means and the end point of the capacitor circuit are Connected via a rectifying element, the change-over switch means has one end at the end. Is connected to one point of the AC connection point of the flow circuit, also the other end connected to a connection point between the switching elements of the power factor correction circuit,
d) DC power supply voltage detection means for detecting a DC power supply voltage output from the rectifier circuit;
e) zero-cross detection means for detecting a zero-cross point of the AC power supply voltage based on the detected DC power-supply voltage and outputting a zero-cross detection signal;
The zero cross detection means includes
Timer means for outputting a zero-cross detection signal after a predetermined delay time (td) has elapsed from the time when the DC power supply voltage reaches a predetermined voltage;
Correction means for correcting the delay time (td) based on the DC power supply voltage detected by the DC power supply voltage detection means,
f) Pulse signal control means for generating and outputting a pulse signal for turning on / off each switching element of the power factor correction circuit based on the zero cross detection signal;
g) A power supply apparatus comprising switch drive means for receiving the pulse signal and driving each switching element of the power factor correction circuit.   DC detection means for detecting an output voltage of the power supply device is further provided, and the pulse signal control means is configured to turn on the switching element of the power factor improvement means according to a change in voltage value detected by the DC voltage detection means. The pulse signal control means changes the maximum value of the on-time (tw) of the switching element based on the value of the DC power supply voltage. Power supply. An air conditioner comprising the power supply device according to any one of claims 1 to 4.

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