JP3519540B2 - DC power supply and air conditioner - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct current power supply device for converting alternating current obtained from an alternating current power supply into direct current and an air conditioner using this direct current power supply device.

[0002]

2. Description of the Related Art A large-capacity direct current power supply device for converting alternating current obtained from an alternating current power supply into direct current, for example, a direct current power supply device capable of supplying power of 200 W to 5 KW, A passive filter method that connects a reactor to the AC power supply path and rectifies the AC obtained through this reactor with a voltage doubler rectifier circuit in order to improve the efficiency and reduce the power supply harmonics (distortion of the current waveform). There is a DC power supply device.

FIG. 19 is a circuit diagram showing the structure of this passive filter type DC power supply device. In the figure, a reactor Lin is connected to one of power supply paths for receiving power from the AC power supply Vin. The AC voltage obtained through the reactor Lin is the diode DH, DL, D3, D4.
Is supplied to the full-wave rectifier circuit composed of. In this case, the series connection circuit of the diodes DH and DL and the diode D
A series connection circuit of D3 and D4 is connected in parallel, a mutual junction point of the diodes DH and DL is connected to one end of the AC power supply Vin via the reactor Lin, and the diodes D3 and D4 are connected.
Is connected to the other end of the AC power supply Vin. A series connection circuit of capacitors CH and CL called an intermediate capacitor is connected in parallel to these diode series circuits, and a mutual junction point of these capacitors is connected to a mutual junction point of diodes D3 and D4. There is. Further, a smoothing capacitor CD and a load resistor RL are connected in parallel to the capacitor series connection circuit.

Here, the AC power source Vin is 100V,
When the load resistance RL of 1.8KW is connected, when the inductance of the reactor Lin is 6.2mH, the capacitance of the intermediate capacitors CH and CL is 360μF, and the capacitance of the smoothing capacitor CD is 1500μF, it is applied to the reactor Lin. Voltage V (Li
n), the current I (Li
n), the voltage V (CH) generated in the capacitor CH with one end of the AC power supply Vin as the reference voltage 0V, and the capacitor CL
The voltage V (CH) generated at the
During the cycle, it changes as shown in the waveform diagram of FIG.

In response to such power supply to the load resistance RL, a power supply harmonic whose component is shown by a current value in FIG. 21 is generated. Figure 21 shows IEC (International Electrotechnical Commission)
It is shown together with the standard, I (Lin) and I (IE
When C) is compared with each frequency component, the third harmonic component of I (Lin) exceeds that of I (IEC).

In order to reduce the third harmonic component, it is possible to use a reactor having a larger inductance, but in this case, there is a problem that the power supply device becomes large. On the other hand, as will be described in detail later, the power factor of the DC power supply device illustrated here is about 93%, and when this DC power supply device is used as a compressor drive power supply of an air conditioner,
As the load increases, the AC input current also increases, and the value easily reaches a predetermined limit value. Therefore, the rotation speed of the compressor is often limited.

The present invention has been made in consideration of the above circumstances, and a direct current power supply device and a direct current power supply device capable of achieving a reduction in harmonic components and a high power factor while suppressing an increase in size of the device. An object is to provide an air conditioner using the.

[0008]

A DC power supply device according to the present invention is a capacitor circuit in which an AC power supply is connected in series with a reactor and a rectifier circuit, and the voltage obtained by rectification is composed of one or a plurality of capacitors. is applied to, in obtaining a smoothed DC voltage to discharge charges charged in the capacitor circuit to the smoothing capacitor, the rectifying times through the reactor
A pair of anti-parallel connections between alternating voltage paths applied to the path
Commutation type switch element, and by turning on the switch element, the forced energization circuit that forces the current from the AC power supply to the reactor and the zero cross point of the AC voltage
Zero-cross point detection means to detect and zero-cross point detection
Indicates that the instantaneous value of the AC power supply matches the voltage across the capacitor.
Rectifying switch corresponding to the polarity of the AC voltage.
Control means for turning on the H-element , which allows the phase to be advanced without changing the effective value of the current flowing in the reactor, and as a result, the harmonic component It is possible to achieve a reduction and a high power factor, and it is possible to suppress the fluctuation of the AC input current due to the fluctuation of the load.

[0009]

[0010]

[0011]

[0012]

[0013]

[0014]

[0015]

In the air conditioner according to the present invention, a reactor and a rectifier circuit are connected in series to an AC power source, and the voltage obtained by rectification is applied to a capacitor circuit composed of one or a plurality of capacitors, and this capacitor is used. The circuit is equipped with a DC power supply device that discharges the electric charge charged in the circuit to a smoothing capacitor to obtain a smoothed DC voltage.The DC voltage output from this DC power supply device is converted into a frequency-variable AC voltage by an inverter device. In an air conditioner that supplies power to the drive motor of the compressor, the switch element is turned on to force a current to flow from the AC power supply to the reactor, and the rotation speed of the drive motor is received from the AC power supply. A control means is provided for changing the phase section of the forced energization of the reactor when limited by the limit value of the maximum possible current. With this configuration, when the rotation speed of the compressor drive motor is limited by the limit value of the maximum current that can be received from the AC power supply, the DC output voltage is increased by changing the forced energization phase section of the DC power supply device, The number can also be increased.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in detail based on the embodiments shown in the drawings. FIG. 1 is a circuit diagram showing the configuration of a first embodiment of a DC power supply device according to the present invention.
This embodiment includes a full-wave rectifier circuit composed of diodes DH, DL, D3 and D4, and the mutual junction point of the diodes DH and DL as one AC input terminal is connected to the AC power source Vin via the reactor Lin. The mutual junction point of the diodes D3 and D4, which are connected to one end and serve as the other AC input terminal, is connected to the other end of the AC power supply Vin. A series connection circuit of intermediate capacitors CH and CL is connected between the DC output terminals of the full-wave rectification circuit, that is, both ends of the series connection circuit of diodes D3 and D4, and the mutual junction point of the diodes D3 and D4 is intermediate. Capacitors CH and C
It is connected to the mutual junction of L. In addition, the smoothing capacitor CD is connected to the series connection circuit of the intermediate capacitors CH and CL.
And the load resistance RL are connected in parallel.

This embodiment is further provided with an AC power source Vin.
An NPN transistor Q forming a forced energization circuit between the load side of the reactor Lin connected to one of the power supply paths and the other power supply path of the AC power supply Vin.
1, Q2 are connected in antiparallel. Then, base driving circuits G1 and G2, which are configured to supply a base current to the bases of these transistors Q1 and Q2, and which are composed of, for example, a base driving power source and a photocoupler, are provided. Further, it is provided with pulse generation circuits I1 and I2 for applying a pulse voltage to the base drive circuits G1 and G2, and a dummy resistor Rdm. The pulse generators I1 and I2 are not described in detail in terms of their configuration, but each is a circuit that detects a zero-cross point of the AC voltage and an AC power supply voltage V that detects the zero-cross point.
It is composed of a pulse current circuit for supplying a pulse current to the dummy resistor Rdm until the instantaneous value of (Lin) becomes equal to the voltage across the intermediate capacitor CH. The pulse generation circuit I1 generates the pulse voltage in the first half of the half cycle of the AC power supply voltage, and the pulse generation circuit I2 generates the pulse voltage in the second half of the half cycle of the AC power supply voltage.

The operation of the first embodiment configured as described above will be described below with reference to FIGS. 2 to 9 obtained by simulating the model. It is assumed that the lower end of the AC power supply Vin shown in the drawing is a reference potential 0V, and a sine wave AC voltage is generated at the upper end of the AC power supply Vin shown in the drawing. In the positive half cycle of this sinusoidal AC voltage, the charging current flows through the intermediate capacitor CH via the reactor Lin and the diode DH. At this time, the diode D4 forms its discharge circuit so that the intermediate capacitor CL is not charged in the opposite direction. Further, in the negative half cycle of the sine wave voltage, the charging current flows to the intermediate capacitor CL via the reactor Lin and the diode DL. At this time, the diode D4 is the intermediate capacitor CH
Form a discharge circuit so that the battery is not charged in the opposite direction.

As long as the intermediate capacitors CH and CL are charged and a voltage of the same direction exists between the terminals, that is, an upward voltage of the drawing, the diodes D3 and D4 do not substantially function, After that, the diode DH
The intermediate capacitor CH is charged via and the intermediate capacitor CL is charged via the diode DL.

In this way, the sum of the terminal voltages of the capacitors CL and CH connected in series is applied to both ends of the smoothing capacitor CD, and the smoothing capacitor CD is charged. That is, the smoothing capacitor CD is charged by discharging the electric charges charged in the intermediate capacitors CL and CH. The sum of the voltages of the capacitors CL and CH connected in series is also supplied to the load resistance RL. At this time, by using the smoothing capacitor CD having a large capacitance, the resistor R
A substantially constant voltage is supplied to L.

In the first half of the half cycle of the AC voltage output from the AC power source Vin, the pulse generating circuit I1 has a transistor Q1, in which the absolute value of the instantaneous value is smaller than the absolute value of the voltage across the intermediate capacitor CH. A pulse voltage for turning on Q2 is generated in the dummy resistor Rdm, and the pulse generating circuit I2 causes the transistor in the predetermined phase section immediately before reaching the zero cross point in the latter half of the half cycle of the AC voltage output from the AC power supply Vin. A pulse voltage for turning on Q1 and Q2 is generated in the dummy resistor Rdm.
Therefore, in these phase sections, the short-circuit current is forced to flow in the reactor Lin, and at the moment when the transistors Q1 and Q2 are turned off, the current flowing in these transistors changes direction to the intermediate capacitors CH and CL. It flows in and forced charging is performed.

Here, the AC power source Vin is 100V,
When the load resistance RL of 1.8 KW is connected, the inductance of the reactor Lin is 6.2 mH and the capacitance of the intermediate capacitors CH and CL is 1000 respectively.
μF, smoothing capacitor CD capacitance 1500
In the case of μF, the voltage V applied to the reactor Lin
(Lin), a current I (L
in), the voltage V (CH) generated in the capacitor CH with one end of the AC power supply Vin as the reference voltage 0V, and the capacitor C
The voltage V (CH) generated in L changes as shown in the waveform diagram of FIG.

In this case, the waveform of the positive half cycle and the waveform of the negative half cycle of the AC voltage are point-symmetric with respect to the zero-cross point. Therefore, in order to avoid redundant description, only the positive half cycle will be described. , A more detailed operation explanation will be given.

It is assumed that the zero crossing point of the AC voltage V (Lin) is time t ₀ , and the time when this voltage V (Lin) is almost equal to the voltage V (CH) of the intermediate capacitor CH is t ₁ . Now, from time t ₀ to time t ₁ , the transistor Q
1 is turned on, and at time t _1, this transistor Q1
Is turned off. As a result, the current I (Lin) flowing in the reactor from time t ₀ to time t _1.
Rapidly increases at the rate of change Vin / Lin. During this period, since the intermediate capacitor CH is not charged, the voltage V (CH) of the intermediate capacitor CH decreases by the amount of the power supplied to the load. Then, the voltage V (L
in) becomes equal to the voltage V (CH) at time t _{1, the} transistor Q1 is turned off. At this moment, the current I (Lin) flowing in the reactor Lin changes direction from the transistor Q1 to the intermediate capacitor CH. Flows in, and the intermediate capacitor CH is charged. For this reason, the voltage V (CH) increases at a large rate of change from time t ₁ despite the large capacitance of the intermediate capacitor CH, and the AC power supply voltage Vin is reached long before the AC power supply voltage Vin reaches the peak value. Approaches the peak value of. Here, the current I (Lin) flowing in the reactor Lin
The change of the direction from the transistor Q1 to the intermediate capacitor CH causes a power source harmonic, but in this case, since the point where the instantaneous value of the AC power supply voltage matches the voltage of the intermediate capacitor is selected, the power source harmonic is selected. The occurrence of is suppressed low.

In such a circuit, the AC power supply voltage Vin and the intermediate capacitor voltage V (C
The current I (Lin) according to the difference with H) flows, but since the difference is small near the peak value of the AC power supply voltage Vin, the subsequent increase rate of the current flowing in the reactor Lin is small. Moreover, it starts to decrease at an early timing.

As described above, when the current flowing through the reactor Lin starts to decrease at an early timing, the increase rate of the voltage V (CH) can be kept low in combination with the large capacitance of the intermediate capacitor CH. This is
The difference from the AC power supply voltage Vin, which has already started to decrease, is suppressed to a small value, and as a result, the reactor current I (Li
The decrease in n) becomes gentle, and the energization section of the reactor Lin can be lengthened, which contributes to the improvement of the power factor.

In the present embodiment, further, the transistor Q1 is turned on during a certain period in the latter half of the positive half cycle, that is, from the time t ₂ to the time t ₃ , so that the current I (Lin) of the reactor Lin in this section. However, the current I (Lin) temporarily increases by changing the direction from the intermediate capacitor CH to the transistor Q1 and flowing. As a result, the timing of ending the energization of the reactor Lin can be further delayed. It should be noted that this control changes the polarity of the current change, which causes a part (for example, 1.05 KHz of FIG. 3 described later) of a higher harmonic component to be increased. ₂ and time width (t
By adjusting the ₂ ~t _3), it can be kept below the required value.

FIG. 3 shows the power supply harmonic components of the first embodiment together with the IEC standard.
The third harmonic component of I (Lin), which was higher than the C standard, can be significantly reduced compared to that of the IEC standard, and the harmonic component can be suppressed to the IEC standard or lower in all frequency ranges. ing.

FIG. 4 shows the instantaneous value and effective value I (Lin) of the input current I (Lin) flowing through the reactor Lin.
The change of _rms is shown together with that of the conventional device.
The maximum value of the input current I (Lin) and the maximum value of the effective value of the present embodiment are suppressed lower than those of the conventional device, and the phase section in which the input current I (Lin) of the present embodiment flows,
That is, it can be seen that the energization section is obviously wider than that of the conventional device.

FIG. 5 is a calculation result of the power factor calculated based on the definition, and shows a cumulative value of the calculation of the power factor Pf until the end of one cycle section of the AC power supply voltage Vin. Although the final cumulative value of power factor was about 93%,
In the present embodiment, the value is over 98%, which shows that the power factor is significantly improved.

FIG. 6 shows the above-mentioned power source harmonic components for the three examples of the conventional example, the IEC standard and this embodiment. In the embodiment, not only the harmonic component can be suppressed to a considerably low level as compared with the conventional example, but also it can be suppressed to 1/2 or less as compared with the IEC standard, and the effect is extremely large.

FIG. 7 shows a voltage of 1 between both ends of the intermediate capacitor CH.
It shows the change of the cycle section, and it is about 2 in the conventional device.
Since it greatly fluctuates from 0 V to a maximum of 230 V, the voltage ripple appearing across the smoothing capacitor CD charged by this voltage and supplied to the load becomes considerably large, whereas in the present embodiment, it is always larger than 100 V and 1
Since it is suppressed to a range smaller than 80 V, it has an effect of suppressing the voltage ripple supplied to the load to be extremely low.

FIG. 8 shows the instantaneous values I (CH), I (CL) and the effective values I (CH) _rms , I (CL) _rms of the charging currents for charging the intermediate capacitors CH, CL, respectively, together with those in the conventional device. Although the conventional device has an instantaneous current waveform similar to the input current waveform (continuous in a sine wave shape), the present embodiment may change greatly by forced energization, but at least the maximum The value is smaller than that of the conventional device, and the effective current value in one charge / discharge cycle shown at the position of 1.000 is also small.

FIG. 9 shows the voltage across the smoothing capacitor CD, that is, the instantaneous value V (CD) and the average value V (C) of the output voltage.
D) _ave (only the numerical value at 1.000 s is valid) is shown together with that of the conventional device. In the conventional device, the voltage value is low and the ripple amount is large. Minutes, higher voltages are obtained.

As is apparent from the above description with reference to the various waveform diagrams of FIGS. 2 to 9, according to the first embodiment, the forced energization circuit for forcibly flowing the current from the AC power supply to the reactor is provided. In the first half of each positive and negative half cycle of the AC power supply, the forced energizing circuit is turned on in the phase section in which the instantaneous value of the AC power supply does not exceed the voltage across the capacitor, and each of the positive and negative AC power supplies. By turning on the forced energization circuit in the predetermined phase section in the latter half of the half cycle, it is possible to reduce the harmonic component and increase the power factor while suppressing the increase in size of the device.

In the above embodiment, the reactor is forcibly energized over the entire phase section in which the instantaneous value of the AC power supply does not exceed the voltage across the capacitor in the first half of each positive and negative half cycle of the AC power supply. Even if the reactor is forcibly energized in a part of the phase section in which the instantaneous value of the AC power supply does not exceed the voltage across the capacitor, the effect similar to that of the above embodiment can be obtained.

In the above embodiment, the forced energizing circuit is turned on in a predetermined phase section in the latter half of each positive and negative half cycle of the AC power source. The effect close to the form is obtained.

FIG. 10 shows a second DC power supply device according to the present invention.
2 is a circuit diagram showing the configuration of the embodiment of FIG. In the figure, the same elements as those of FIG. 1 showing the first embodiment are designated by the same reference numerals, and the description thereof will be omitted. In this embodiment, the reactor Lin
In place of the transistors Q1 and Q2 for forcibly energizing the diode, a full-wave rectifying diode bridge formed by connecting diodes D5 to D8 in a bridge connection and a transistor Q1 that controls the current of the full-wave rectifying diode bridge are used. is there. In this case, one of the AC input terminals of the full-wave rectification diode bridge is connected to the load side of the reactor Lin connected to one end of the AC power supply Vin, and the other of the AC input terminals of the full-wave rectification diode bridge is the AC power supply Vin.
Is connected to the other end of. Further, a transistor Q1 is connected between the DC output terminals of the full-wave rectification diode bridge, and the transistor Q1 is driven by the base drive circuit G1. According to this embodiment, there is an advantage that one set of the transistor and its base drive circuit is sufficient. Further, when the above-mentioned transistor Q1 is a rectifying type switch element, the full-wave rectifying diode bridge itself has a rectifying characteristic, so that a simple switch element may be used instead of the transistor Q1.

Thus, also in the second embodiment, by turning on the transistor in part or all of the phase section in which the instantaneous value of the AC power supply Vin does not exceed the voltage across the intermediate capacitor C, It is possible to reduce harmonic components and increase the power factor while suppressing the increase in size of the device.

FIG. 11 shows a third DC power supply device according to the present invention.
2 is a circuit diagram showing the configuration of the embodiment of FIG. In the figure, the same elements as those of FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.
In this embodiment, an AC voltage obtained via a reactor Lin is applied to an AC input terminal of a full-wave rectifier circuit in which diodes D1 to D4 are bridge-connected, and its output is charged in an intermediate capacitor C, and this intermediate capacitor is charged. The electric charge of C is discharged to the smoothing capacitor CD, and a DC voltage is supplied to the load resistor RL. In this case, the diode D
The transistor Q1 is connected to the positive and negative DC current paths connecting the full-wave rectifier circuit 1 to D4 and the intermediate capacitor C,
The base drive circuit G1 drives the transistor Q1. When the transistor Q1 is turned on and a current is forced to flow through the reactor Lin, the backflow prevention diode D11 is connected so that the electric charge of the intermediate capacitor C is not discharged through the transistor Q1. In the path for discharging the electric charge of the
And a reactor Ldc that enhances the smoothing effect are connected in series.

Also according to the third embodiment, the device is provided by turning on the transistor in a part or all of the phase section in which the instantaneous value of the AC power supply Vin does not exceed the voltage across the intermediate capacitor C. It is possible to reduce the harmonic components and increase the power factor while suppressing the increase in size.

FIG. 12 shows a fourth DC power supply device according to the present invention.
12 is a circuit diagram showing the configuration of the embodiment of FIG. 11, in which the same elements as those of FIG. 11 showing the third embodiment are designated by the same reference numerals and the description thereof will be omitted. In this embodiment, the reactor Lin connected to the AC power supply path is replaced by the diodes D1 to D1.
It differs from FIG. 11 in that the connection is changed to a path connecting the full-wave rectification circuit D4 and the intermediate capacitor C. The transistor Q is connected to the load side of the reactor Lin.
1 is connected to drive this transistor.

Also according to the fourth embodiment, the transistor Q1 is used in a part or all of the phase section in which the instantaneous value of the AC power source Vin does not exceed the voltage across the intermediate capacitor C.
By turning on the switch, it is possible to reduce the harmonic components and increase the power factor while suppressing the increase in size of the device, and a single switch element is required as the forced energizing circuit. There are also advantages.

FIG. 13 shows a fifth embodiment of the DC power supply device according to the present invention.
12 is a circuit diagram showing the configuration of the embodiment of FIG. 11, in which instead of the base drive circuit G1 and the transistor Q1 in FIG.
This is replaced with a combination of the full-wave rectification diode bridge of D8 and the transistor Q1 that controls the current of the full-wave rectification diode bridge. In this configuration, the element corresponding to the diode D11 in FIGS. 11 and 12 is unnecessary. Therefore, the number of elements in the path supplied from the full-wave rectification circuit of the diodes D1 to D4 to the load side is reduced, and the loss due to the circuit elements can be reduced.

FIG. 14 shows a sixth embodiment of the DC power supply device according to the present invention.
2 is a circuit diagram showing the configuration of the embodiment of FIG. In the figure, the same elements as those of FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.
In the first embodiment shown in FIG. 1, transistors Q1 and Q2 are connected in antiparallel to the load side of a reactor Lin connected to an AC power source Vin, and these transistors are driven by base drive circuits G1 and G2. However, in the sixth embodiment, the transistor Q1 is connected to the DC voltage path in the front stage of the intermediate capacitor CH of the voltage doubler rectifier circuit, and the transistor Q2 is connected to the DC voltage path in the front stage of another intermediate capacitor CL. By turning on these transistors, the current is forced to flow through the reactor Lin. In this case, the intermediate capacitor C
A backflow prevention diode D11 is connected so that the H charge is not discharged through the transistor Q1, and the backflow prevention diode D11 is further connected so that the charge of the intermediate capacitor CL is not discharged through the transistor Q2.
12 are connected.

Also according to the sixth embodiment, the transistor Q is provided in a part or all of the phase section in which the instantaneous value of the AC power source Vin does not exceed the voltage across the intermediate capacitor C.
By turning on 1 and Q2, it is possible to reduce the harmonic component and increase the power factor while suppressing the increase in size of the device.

FIG. 15 is a block diagram showing the configuration of an embodiment of an air conditioner to which the above DC power supply device is applied.
In this embodiment, a direct current power supply device as a converter device for converting alternating current to direct current, and an inverter device for converting direct current output from the direct current power supply device into alternating current of variable voltage and variable frequency and supplying it to a compressor driving motor. Is equipped with.
The DC power supply device used here is the one illustrated in FIG. 10. As the base drive circuit G1 in FIG. 10, a base drive power supply 13 and a photocoupler 19 are provided, and an inverter device 20 is used instead of the load resistance RL. Through the compressor drive motor
21 is connected. Further, the zero-cross detector 14 and the outdoor controller 15 are provided with the function of the pulse generating circuit shown in FIG.

This air conditioner is composed of an indoor unit and an outdoor unit, and the indoor unit is connected to an AC power source. In the indoor unit, the operating power is supplied from the AC power supply 1 to the indoor control unit 3 via the noise filter 2. The indoor control unit 3 includes a receiving unit 5 that receives a command from the remote control device 4, a temperature sensor 6 that detects the indoor temperature, an indoor fan 8 that circulates the air indoors through an indoor heat exchanger (not shown), and the direction of blown air. A louver 9 for changing the is connected. On the other hand, also in the outdoor unit, operating power is supplied from the AC power supply 1 to the outdoor control unit 15 and the compressor drive motor 21 via the noise filter 11. In this case, the current value detector 12 is provided on the load side of the noise filter 11, and the detection signal thereof is input to the outdoor control unit 15. In addition, the zero-cross detector 14 that detects the zero-cross point by monitoring the AC voltage on the load side of the noise filter 11
Is provided, and the detection signal thereof is input to the outdoor control unit 15. The outdoor control unit 15 further includes a temperature sensor 16 that detects the temperature of the outdoor heat exchanger, a four-way valve 17 that changes the circulation direction of the refrigerant according to the operation mode, and an outdoor unit that sends air to an outdoor heat exchanger (not shown). The fan 18 is connected. Further, the outdoor control unit 15 is configured to transmit and receive with the indoor control unit 3 to control the inverter device 20, and to supply a pulse current to the photocoupler 19 to turn on the transistor Q1.

The general operation of the embodiment of the air conditioner configured as described above will be described below. First, commands such as operation start, operation mode, indoor set temperature, indoor fan wind speed, and wind direction are applied from the remote control device 4 to the indoor control unit 3 via the receiving unit 5. In response to this, the indoor control unit 3 displays the operating state and the like on the display device 7 and executes the drive control of the indoor fan 8 and the louver 9, and at the same time, the compressor drive motor 21 according to the deviation between the set temperature and the indoor temperature. A power supply frequency (hereinafter referred to as compressor frequency) for driving the compressor is calculated, and the compressor frequency signal is transmitted to the outdoor control unit 15 together with the operation mode signal. The outdoor control unit 15 puts the four-way valve 17 into an excited (or non-excited) state according to the operation mode signal, controls the inverter device 20 according to the compressor frequency, drives the outdoor fan 18, and outputs a detection signal from the temperature sensor 16 and the like. The four-way valve 17 is controlled to perform defrosting operation or the like. Further, the outdoor control unit 15 also corrects the compressor frequency so that the current detection value by the current value detector 12 does not exceed the preset limit value. Further, the outdoor control unit 15 also executes forced energization control for the reactor Lin that constitutes the DC power supply device. Outdoor control unit
This 15 is to reduce the harmonics of the power supply and improve the power factor by this forced energization control, and at the same time, when the current detection value by the current value detector 12 is about to exceed the limit value specified by the plug or the outlet, the reactor By adjusting the phase section of forced energization for Lin, control is performed to supply more electric power to the compressor drive motor 21 within the specified limit value.

Hereinafter, as long as the outdoor control unit 15 does not exceed the limit value specified by the plug or outlet, the reactor Li
The point of increasing the power supply by adjusting the phase section of forced energization for n will be described in detail. The DC power supply device shown in FIG. 15 uses the one illustrated in FIG. 10, but its current, voltage, harmonic component, power factor, etc. are the same as those described with reference to FIGS. 2 to 9. By the way, in the apparatus illustrated in FIG. 10, the load resistance RL is kept constant and the reactor Lin is forcibly energized. However, when this DC power supply is applied to an air conditioner, the capacity of the compressor changes according to the fluctuation of the air conditioning load. Since it is controlled, the forced energization phase of the reactor Lin must be determined on the assumption that the load resistance RL changes.

Therefore, a simulation was carried out with the combination of the load resistance RL and the turn-off timing of the transistor Q1 forming the forced energizing circuit, as shown in Table 1 below.

[0053]

[Table 1] According to this simulation, in one cycle of the AC power supply voltage, the reactor current I (Lin) is as shown in FIG. 16, the cumulative value of the power factor Pf is as shown in FIG. 17, and the output voltage cumulative value is as shown in FIG. The DC output voltage, the power factor, the actual value of the input current, and the input power shown in Table 1 were calculated correspondingly.

The simulation waveforms A, B, ..., H shown in FIGS.
It corresponds to each parameter in the columns of B, ..., H,
The turn-on timing of the transistor Q1 is the result when 0.1 ms (msec) is measured from the zero-cross point.

From Table 1, at least the following (a),
The contents of item (b) can be read. (A) By delaying the turn-off timing of the transistor Q1, the DC output voltage can be increased.

The effects (a) and (b) obtained by adjusting the OFF timing of the short-circuit element are useful as a power source for a device mainly including an electric motor, not limited to an air conditioner as a built-in device. . (B) Even if the load resistance RL changes and the required voltage changes,
Forced energization of the reactor according to the size of the load connected to the DC power supply (achieved with conventional equipment by appropriately selecting or changing the off-timing section within the set phase section and within the range of the input current limit value) It is possible to reduce the harmonics that could not be achieved and to operate with a high power factor.

Thus, by applying any of the DC power supply devices illustrated in FIGS. 1 and 10 to 14 to the air conditioner, the input current defined by the plug or the outlet, for example, 15 A Alternatively, since a large amount of electric power can be supplied to the compressor driving electric motor while keeping the range of 20 A, the air conditioning capacity can be improved by multiplying the electric power used by EER (Energy Efficiency Ratio).

Further, since a larger DC output voltage can be obtained as compared with the conventional device, the DC is used as the compressor driving motor.
It is possible to rotate at high speed even when using a brushless motor, and it is possible to supply the required voltage when low torque and high speed rotation are required, such as when starting heating operation under conditions where the temperature is extremely low. . Even when an induction motor is used as the compressor drive motor, the voltage frequency ratio V /
A motor having a large F can be used, which has the effect of reducing the operating current during normal operation.

Furthermore, since the DC output voltage can be adjusted while maintaining a high power factor by changing the phase section in which the power is forcibly energized, the duty is fixed to 100% instead of PWM control by the inverter device. By adjusting the forced energization phase section to control the speed of the motor, it is possible to reduce the switching loss of the inverter element.
There is also an effect that the leak current can be suppressed low.

[0060]

As is apparent from the above description, according to the DC power supply device of the present invention, a positive energizing circuit connected to the AC power supply in series with the reactor is provided, and the positive and negative AC power supplies are provided. By forcibly flowing the current through the reactor in the specified phase section in the first half of the half cycle, the phase is advanced without changing the effective value of the current flowing through the reactor, and the harmonic components It is possible to achieve a reduction and a high power factor, and it is possible to suppress the fluctuation of the AC input current due to the fluctuation of the load.

In this case, the current value of the AC power source is forcibly energized in a part or all of the phase section where the voltage across the capacitor does not exceed the voltage across the capacitor, so that the current phase of the reactor is advanced and the harmonic component is reduced and the power is reduced. A rationalization is achieved.

Further, by forcibly energizing the reactor also in a part of the latter half of each of the positive and negative half cycles of the AC power supply, the energizing section of the reactor is expanded and the effect of increasing the power factor is enhanced.

Further, in order to forcibly energize the reactor, zero-cross detecting means for detecting the zero-cross point of the AC voltage, and from the detection of the zero-cross point until the instantaneous value of the AC power supply coincides with the voltage across the capacitor, respectively. Reliable control can be performed by controlling the on / off control of the rectifying switch element corresponding to the polarity.

An air conditioner according to another aspect of the present invention uses the above-mentioned DC power supply device as a converter device for converting alternating current into direct current, so that the compressor can be operated within the limit range of the input current specified for the plug and the outlet. The power supplied to the drive motor can be increased, and the air conditioning capacity can be significantly improved.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of a first embodiment of a DC power supply device according to the present invention.

FIG. 2 is a diagram showing a relationship between current and voltage and time for explaining the operation of the DC power supply device shown in FIG.

FIG. 3 is a diagram (I) showing a relationship between a harmonic component and a frequency in order to explain the operation of the DC power supply device shown in FIG.
(Lin) _rms is valid only for the data of the points that indicate numerical values.

FIG. 4 is a diagram showing a relationship between a reactor current and time in order to explain the operation of the DC power supply device shown in FIG. 1.

5 is a diagram showing the relationship between the cumulative value of the power factor and time in order to explain the operation of the DC power supply device shown in FIG. 1 (only the data at the points indicating numerical values are valid).

FIG. 6 is a diagram showing a relationship between harmonic components and frequencies for explaining the operation of the DC power supply device shown in FIG.

7 is a diagram showing the relationship between the voltage of an intermediate capacitor and time for explaining the operation of the DC power supply device shown in FIG.

To illustrate the operation of the DC power supply apparatus shown in FIG. 8] FIG. 1, a line diagram showing the relationship between the charging current and time of intermediate capacitor (I (Lin) _rms only data points showing the numerical value Effectiveness).

9 is a diagram (V showing the relationship between DC output voltage and time) for explaining the operation of the DC power supply device shown in FIG.
(CD) _ave is valid only for the data of the points that show numerical values).

FIG. 10 is a circuit diagram showing a configuration of a second embodiment of a DC power supply device according to the present invention.

FIG. 11 is a circuit diagram showing a configuration of a third embodiment of a DC power supply device according to the present invention.

FIG. 12 is a circuit diagram showing the configuration of a fourth embodiment of a DC power supply device according to the present invention.

FIG. 13 is a circuit diagram showing a configuration of a fifth embodiment of a DC power supply device according to the present invention.

FIG. 14 is a circuit diagram showing the configuration of a sixth embodiment of a DC power supply device according to the present invention.

FIG. 15 is a block diagram showing a configuration of an embodiment of an air conditioner according to the present invention.

16 is a diagram showing a relationship between a reactor current and time in order to explain the operation of the air conditioner shown in FIG.

FIG. 17 is a diagram showing the relationship between the cumulative value of the power factor and time for explaining the operation of the air conditioner shown in FIG.

18 is a diagram showing the relationship between the cumulative value of the DC output voltage and time for explaining the operation of the air conditioner shown in FIG.

FIG. 19 is a circuit diagram showing a configuration of a conventional DC power supply device.

20 is a diagram showing the relationship between the current of the reactor and the voltage of the intermediate capacitor and time for explaining the operation of the DC power supply device shown in FIG.

FIG. 21 is a diagram showing the relationship between harmonic components and frequencies for explaining the operation of the DC power supply device shown in FIG.

[Explanation of symbols]

Vin AC power supply Lin reactor D1 to D8, D11 to D13, DH, DL diode C, CH, CL Intermediate capacitor CD smoothing capacitor RL load resistance Q1, Q2 transistor G1, G2 base drive circuit I1, I2 pulse generation circuit 1 AC power supply 3 Indoor control unit 12 Current value detector 13 Base drive power supply 14 Zero cross detector 15 Outdoor control unit 20 Inverter device 21 Compressor drive motor

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Claims (2)

(57) [Claims] 1. A reactor and a rectifier circuit are connected in series to an AC power source, the voltage obtained by rectification is applied to a capacitor circuit composed of one or a plurality of capacitors, and the charges charged in this capacitor circuit are applied. In a DC power supply device that obtains a smoothed DC voltage by discharging into a smoothing capacitor, an AC applied to the rectifier circuit via the reactor.
A pair of rectifying switch elements connected in anti-parallel between voltage paths
A forced energizing circuit that is a child and forcibly supplies a current from the AC power supply to the reactor by turning on the switch element, and a zero-cross point detecting means for detecting a zero-cross point of the AC voltage.
Stage and the zero-cross point detection, the instantaneous value of the AC power supply
The polarity of the AC voltage until it matches the voltage across the sensor.
And a control means for turning on the rectifying type switch element corresponding to the above . 2. A reactor and a rectifier circuit are connected in series to an AC power source, the voltage obtained by rectification is applied to a capacitor circuit composed of one or a plurality of capacitors, and the charges charged in this capacitor circuit are applied. Equipped with a DC power supply device that discharges to a smoothing capacitor to obtain a smoothed DC voltage.The DC voltage output from this DC power supply device is converted into a frequency variable AC voltage by an inverter device to supply power to the compressor drive motor. In the air conditioner to be supplied, a forced energization circuit for forcibly flowing current from the AC power supply to the reactor by turning on a switch element, and the rotation speed of the drive motor are the maximum that can be received from the AC power supply. When it is limited by the current limit value, a control means for changing the phase section of the forced energization of the reactor is provided to increase the DC output voltage. The air conditioner is characterized in that to enable an increase in the rotational speed of the drive motor.