JP3485047B2 - 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 DC power supply device used in an air conditioner, etc.
The present invention relates to a direct-current power supply device that suppresses harmonics so that the amount of generated harmonics is below a limit value of harmonic regulation.

[0002]

2. Description of the Related Art FIG. 15 shows, for example, Japanese Patent Laid-Open No. 5-33674.
It is a block diagram which shows the structure of the conventional DC power supply device shown by the 7th publication. In the figure, 1 is an AC power supply, 2 is a rectifier circuit for full-wave rectifying the voltage of the AC power supply 1, 7 is a load, 33
Is a transformer provided on the output side of the rectifier circuit 2 through a smoothing capacitor C1, and 34 is a primary coil L of the transformer 33.
1 is a field effect transistor (hereinafter, referred to as FET) for controlling the voltage applied to 1; 35 is a first comparator for comparing the voltage applied to the load 7 and the reference voltage Vref; and 36 is a triangular wave for generating and outputting a triangular wave. A generator, 37 is a second comparator for comparing the result of the first comparator 35 with the triangular wave output from the triangular wave generator 36, and 38 is a second FET for the FET 34.
Is a driver that outputs a drive pulse to the gate of the FET 34 based on the output from the comparator 37, and 39 is a line filter that removes noise on the voltage supplied from the AC power supply 1 and outputs it to the rectifier circuit 2. is there.

Next, the operation of the conventional DC power supply device will be described. The first comparator 35 detects the voltage corresponding to the current flowing through the load 7, compares it with the reference voltage Vref, and outputs the compared difference to the second comparator 37. Second comparator 3
Reference numeral 7 compares the difference output from the first comparator 35 with the triangular wave of the triangular wave generator 36, and switches the FET 34 with a drive pulse having a pulse width determined according to the detected voltage, so that the FET 34 is smoothed and stabilized. DC voltage is load 7
Is supplied to.

[0004]

In the above-mentioned conventional DC power supply device, when the switching operation of the FET 34 is performed at a constant cycle, the output voltage changes depending on the load amount, so that it corresponds to the current flowing through the load 7. Voltage is detected, the first comparator 35 compares it with the reference voltage to obtain the difference, and the second comparator 37 compares the difference of the first comparator 35 with the triangular wave of the triangular wave generator 36. FET3 according to the detected voltage
Although the ratio of the pulse width of the drive pulse for switching 4 is changed, if the load amount fluctuation width of the load 7 becomes too large, the output voltage will be greatly boosted, so feedback control must be performed. There was a problem. If the DC power supply is applied to a model with a wide operating range, such as an air conditioner, the output voltage will be greatly boosted, and components with high breakdown voltage must be used. It was Further, in order to prevent the output voltage from being boosted, very high speed control is required as the loop speed of feedback control, and in order to realize high speed control, parts capable of high speed processing are required, Further, the control becomes complicated, which leads to an increase in cost.

Further, when such a conventional DC power supply device is applied to an air conditioner, while the air conditioner is operating,
Since the FET 34 continues to operate, there is a problem that switching loss occurs in the FET 34 and efficiency decreases, and when high-speed switching is performed in the FET 34, noise occurs and the line filter 29 becomes enlarged. Such problems also occurred.

The present invention has been made in order to solve the above-mentioned problems, and does not always cause the switching element to perform a switching operation, but reduces the number of times of switching, thereby increasing the speed of processing in control. (EN) A control device for a DC power supply, which can lower and reduce harmonics at low cost.

[0007]

The air conditioner of the present invention comprises:
A rectifying circuit for rectifying the voltage of the AC power supply, a smoothing capacitor for smoothing the output voltage from the rectifying circuit, and a switch means arranged on the AC power supply side of the smoothing capacitor,
The reactor arranged on the power supply side of the switch means and the harmonic amount of the input current for each of the load amounts are equal to or less than the regulation value in advance.
The opening and closing time of the switch means that becomes the lower, the load amount
Storage means for storing in correspondence with each, and load detecting means for detecting a load of the parallel load connected to the smoothing capacitor, a load amount detected by the load detecting means
The opening / closing time of the switch means corresponding to
From the selecting means and at least twice in a half cycle of the power source in synchronization with the power source cycle of the AC power source .
The switch means is opened at the selected opening / closing time.
A DC power supply device having control means for controlling the closing of the compressor
It is a DC power supply device .

When the switching means switches between the DC bus voltage on the output side of the rectifying circuit,
It is provided with a diode for preventing backflow from the smoothing capacitor to the switch means.

Further, a rectifier circuit for rectifying the voltage of the AC power supply, a smoothing capacitor for smoothing the output voltage from the rectifier circuit, a switch means arranged on the AC power supply side of the smoothing capacitor, and a power supply for the switch means. Side reactor, an inverter connected in parallel with the smoothing capacitor, and the operation mode and operation mode of the air conditioner in advance.
And the harmonic content of the input current for each inverter frequency is below the regulation value.
The opening and closing time of the switch means that is below
Correspond to each operation mode and inverter frequency
Storage means for storing the data, an inverter control section for driving and controlling the inverter at a desired inverter frequency, and an air conditioner.
Before the operation mode of the washi machine and the inverter frequency
The opening / closing time of the switch means is selected from the storage means.
And selection means, the synchronization with the power source period of the AC power supply at least two times the power supply half cycle is selected by said selection means
A control for opening / closing the switch means at the opening / closing time.
A DC power supply device equipped with a control means
It is obtained by the. .

Further, the control means is controlled by the AC power source.
The switching means is controlled to open and close at least twice during a period in which an input current generated by the rectifying circuit and the smoothing capacitor does not flow.

The control means is for opening and closing the switch means.
The switch means is controlled to open and close at intervals of continuous input current.
Control .

[0012]

The load amount detecting means is a compressor.
The amount of load that can be obtained is detected .

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. 1 is a block diagram showing the configuration of a DC power supply device according to a first embodiment of the present invention. In FIG. 1, 1 is an AC power supply, 2 is a full-wave rectifier circuit composed of four diodes for full-wave rectifying the voltage of the AC power supply 1, and 3 is one end side connected to the positive output side of the full-wave rectifier circuit 2. A DC reactor 4 for storing energy and smoothing current is a smoothing capacitor provided between the other end side of the DC reactor 3 and the negative output side of the full-wave rectifier circuit 2 for smoothing a DC bus voltage. Reference numeral 5 denotes a reverse current blocking diode which is provided between the other end of the DC reactor 3 and the positive side of the smoothing capacitor 4 and blocks reverse current from flowing from the smoothing capacitor 4 side to the full-wave rectifier 2.

Reference numeral 6 is a switch means provided between the other end of the DC reactor 3 and the negative output side of the full-wave rectifier circuit 2 for switching between the DC buses, and 7 is a load connected in parallel with the smoothing capacitor 4, Reference numeral 8 is a control means for controlling opening / closing of the switch means 6 at least twice in a half cycle of the power supply based on a power supply synchronizing signal generated from the voltage of the AC power supply 1, and 9 is a load amount of the load 7. Storage means for storing the data of the opening / closing time of the switch means 6 preset according to the above, 10 is a load amount detecting means for detecting the load amount of the load 7, and 11 is the load amount detecting means 10. It is a selection unit that appropriately selects the switch opening / closing time stored in advance in the storage unit 9 according to the load amount.

Next, the operation of the DC power supply device according to the first embodiment of the present invention will be described. Before that, first, the relationship between the input voltage and the input current when the switch means 6 shown in FIG. 1 does not operate at all will be described. When the switch means 6 does not operate at all, only when the DC voltage smoothed by the smoothing capacitor 4 and the AC input voltage applied by the AC power supply 1 are compared, the input voltage is higher than the DC voltage. Since the current flows from the AC power supply 1, an input current as shown in FIG. 2 flows, but this current contains a large amount of harmonic components, and this current has a large phase difference from the input voltage. The power factor is also bad.

Therefore, the switch means 6 as shown in FIG.
When the switch means 6 is operated several times during the period in which the input current does not flow in the half cycle of the power supply,
A current path that flows from the AC power supply 1 through the full-wave rectifier 2, the DC reactor 3, the switch means 6, the full-wave rectifier 2, and the AC power supply 1 is formed. After the switch means 6 has been turned on and closed, the input current will not be interrupted even if the switch means 6 is opened thereafter. This is due to the property of the DC reactor 3, and since the reactor has a property of trying to keep the current flowing, the energy stored in the reactor is charged in the smoothing capacitor 4 so that the input current flows. Therefore, the input current continues to flow until the energy stored in the DC reactor 3 is consumed.

FIG. 3 is a waveform diagram showing the relationship between the input current and the input voltage when the switch means 6 is operated only twice during the period in which the input current flows immediately after the zero cross point in FIG. . Note that Tsw1 is the first delay time until the switch means 6 is closed, and Ton1 is the switch means 6
Is the first closing time, Tsw2 is the second delay time until the switching means 6 is closed, and Ton2 is the second closing time when the switching means 6 is closed. When the switch means 6 is closed after passing through the zero-cross point, a current path is formed and a current flows as described above. Even when the switch means 6 is opened, energy is accumulated in the DC reactor 3, and the DC reactor 3 works to flow a current by the amount of energy of the DC reactor 3, and the switch means 6 is activated before the current becomes zero. Perform the second switch operation. Then, after the switch means 6 is turned off for the second time, the input voltage becomes higher than the DC voltage and a current flows, resulting in an input current waveform as shown in FIG. In this way, by operating the switch means 6 to flow the current during the period when the input current does not flow, the phase difference between the voltage and the current is reduced, and the power factor is improved. Further, by controlling the operation timing of the switch means 6, the input current flows not only near the peak but also near the zero cross, so that harmonics are reduced.

Next, the operation of the DC power supply device according to the first embodiment of the present invention shown in FIG. 1 will be described. When power is supplied from the AC power supply 1, the circuit operates and the load 7 operates. Here, the load 7 works by obtaining power by driving the motor, and the drive portion for driving the motor is also a part of the load. The motor may be a DC motor or an AC motor, but in the case of a load that obtains power from the AC motor, the DC-AC converter is also part of the load. For example, the compressor used in the air conditioner is a load not only for the compressor motor, but also for the entire compressor and the drive portion that drives the compressor motor.

When such a load 7 is operating, the load amount detecting means 10 detects the load amount. Then, the detected load amount is transmitted to the selection means 11. Here, the load amount detected by the load amount detecting means 10 may be the number of rotations of the motor or the torque generated by the motor, but the load is the compressor used in the air conditioner. In this case, since the load amount detecting means 10 cannot detect the rotation speed of the motor, the load amount is, for example, the induced voltage from the motor or the flow rate of the refrigerant. Next, the selection means 11
In order to open / close the switch of the switch means 6 appropriately, the opening / closing time of the switch means 6 according to the load amount detected by the load amount detecting means 10 is selected from the storage means 9,
Notify the control means 8. Here, the storage means 9 stores the opening / closing time according to the load amount in advance, and the switching means 6
The switch is operated at an appropriate opening / closing time according to the load.

The control means 8 controls the switch means 6 to open and close in the opening and closing time transmitted from the selecting means 11. Here, the reference of the switching timing of the switch means 6 is based on the signal generated by the power supply synchronization signal generation means built in the control means 8 from the power supply synchronization signal input from the AC power supply 1. That is, the control means 8 is based on the zero-cross point at which the input voltage of the AC power supply 1 crosses the midpoint of zero volt, and the switch means 6 is opened and closed by counting the time for opening and closing the switch means 6 from the reference point. Control.

Although it is necessary to synchronize with the power source in this way, in the control according to the present invention, the error of power source synchronization affects the effect of suppressing harmonics. The reason is that the control according to the present invention is configured to control at the switching timing from the true zero-cross point, but when the detected zero-cross point is delayed from the true zero-cross point, the switching timing is changed. Will approach the peak of the fundamental wave. In the present invention, the third-order component is suppressed by causing the current to flow before the peak of the fundamental wave. Therefore, if the delay occurs after the true zero-cross point, the amount of the third-order component suppressed by the control is reduced. Because it will be more than. On the contrary, if the measurement of the switching timing is started earlier than the true zero-cross point, the reduced third-order components are dispersed to the higher third-order components and higher components. This is because it is necessary to reduce the synchronization error. However, in terms of air conditioners,
If there is an error in the power supply synchronization signal generation means used in the current product, there is no problem level. Therefore, when applied to an air conditioner, the switch means 6 is used at the power supply synchronization level of the current power supply synchronization signal generation means. It doesn't matter if you run.

Here, for example, the AC power source 1 has a frequency of 50.
In the case of Hz, there are zero cross points twice in one cycle. In other words, the zero-cross point exists once in a half cycle of the AC power supply 1, and the cycle of the power supply is 20 ms.
There will be a zero-cross point once every 0 ms.
Furthermore, if the control means 8 switches the switching means 6 only twice in a half cycle of the power supply, an input current as shown in FIG. 3 flows, the power factor is improved, and harmonics are reduced. Since the control as described above only operates the switch means 6 several times in 10 ms, there is almost no processing load on the control system generated by controlling the switch means 6. Therefore, the control becomes simple, and there is almost no increase in cost caused by executing the control.

In FIG. 3, the switch means 6 is opened and closed only twice in a half cycle of the power source, but it is not limited to two times, and it is said that the same effect can be obtained if the opening and closing is performed twice or several times. There is no end. On the other hand, in order to suppress harmonics, switching only once every half cycle of the power supply requires the DC reactor 3
Inductance value becomes large and the external shape becomes large. This is because when the input current becomes zero after the input current is made to flow by the operation of the switch means 6, not only the power factor deteriorates, but also the amount of higher harmonic components becomes higher than usual. Also, it is necessary to store a large amount of energy in the DC reactor 3 in order to prevent the input current from becoming zero with only one switch. On the contrary, if the time for which the switch means 6 is closed is lengthened, the steep current becomes too large, and the switch means 6 is closed.
May be damaged and harmonics may not be suppressed. Also, when the inductance value increases, the DC reactor 3
Fever becomes large. Therefore, the switch means 6 is set to 1
Switching multiple times is preferred over switching only once.

Next, a method of setting the reactor value and the opening / closing time will be described below. FIG. 4 is a flowchart illustrating a method of setting the reactor value. In step 1, the load amount of the load 7 is set. Here, when a load whose load amount changes as the load 7, for example, a load such as a compressor of an air conditioner is used, the regulation of the power supply harmonics is as follows.
Since it is specified that the measurement should be performed at the maximum rated operation, the load amount at the maximum rated is set. In step 2, the inductance value of the DC reactor 7 is set. In step 3, a combination of opening / closing times of several times of switching operations in the switching means 6 is set. The input current calculation in step 4 is to calculate the input current waveform in the circuit using the setting data up to step 3.

Step 5 is FFT analysis calculation for performing fast Fourier expansion (FFT) of the input current waveform calculated in step 4 to calculate a harmonic component. In step 6, the harmonic amount of the input current calculated for each order in step 5 is compared with the regulation value. In step 7, if the comparison result is not less than the regulation value, steps 2, 3 Change the setting data in. If the regulation value is satisfied, the setting data in steps 2 and 3 and the FFT analysis data of the input current are output in step 8. In FIG. 4, the process ends in step 8, but in order to obtain the setting for suppressing the harmonics, a loop for returning to step 2 after step 8 is created, or returning to step 3, There is no problem even if you create data of combinations of switching times at regular intervals, perform steps such as input current calculation and FFT analysis calculation with other setting data, and obtain other setting data that suppresses harmonics. Absent.

As a result of simulating the generation amount of harmonics in the air conditioner having the configuration as shown in FIG. 1, with the reactor value of the DC reactor 3 and the opening / closing time of the switch means 6 set by the method as shown in FIG. Is shown in FIG. FIG. 5 is a graph comparing the analysis result with the harmonic regulation value, the bar graph shows the analysis result of the amount of generated harmonics, and the line graph shows the harmonic regulation value. The simulation shown in FIG. 5 is based on an air conditioner with an output power of 3300 W as a model. The set value for the analysis is that the reactor value of the DC reactor 3 is 3 mH, and the first delay time until the switch means 6 is closed. Tsw1 is 1.9 ms, the first closing time Ton1 for closing the switch means 6 is 0.3 ms, and the switch means 6 is
The second delay time Tsw2 before closing
The second closing time Ton2 for closing the switch means 6 is 0.1 ms.

The simulation of FIG. 5 shows that the output power is 33
FIG. 6 shows the result of the simulation at 2200 W when it was at 00 W. The difference between the set values in Fig. 6 and Fig. 5 is only the opening / closing time and the reactor value is the same.
It is mH. For the opening / closing time of the switch unit 6,
sw1 = 2.4 ms, Ton1 = 0.1 ms, Tsw2
= 0.2 ms and Ton2 = 0.2 ms. From FIG. 6, by changing the opening / closing time for operating the switch means 6, it is possible to cope with a load such as an air conditioner in which the load amount varies. Further, this time, the switch means 6 was operated only twice in the half cycle of the power supply, but if the number of times the switch means 6 is operated is increased, the reactor value required to obtain the equivalent harmonic suppression effect is decreased. However, the number of times of switching to be increased is about several times, and if the number of times of switching is increased too much, not only the above-mentioned problem of boosting arises but also the cost increases due to an increase in the processing load of the control system.

When the switch means 6 is operated once and a model of an air conditioner having a 3300 W output is simulated, the reactor value of the DC reactor 3 is 4 mH and the opening / closing time of the switch means 6 is Tsw.
When 1 = 2.3 ms and Ton1 = 0.35 ms, it is possible to suppress the amount of harmonic generation that satisfies the harmonic regulation value, but when the number of switches is one, the reactor of the DC reactor 3 is more than twice the number of switches. The value increases. FIG. 7 shows a comparison between the simulation result and the regulation value when the number of switches is one. When the reactor value becomes large, there is a problem that the DC reactor 3 generates a large amount of heat and the external shape of the DC reactor 3 itself becomes large, so that the boosting region is not reached, such as 2 times or 3 times the number of times of switching once. It is clear that a few switches is better. The step-up region mentioned here means an on-time of switching for flowing a current amount such that the DC bus voltage rises.

Further, if the load amount of the load 7 changes with one switch, the harmonic regulation value cannot be satisfied only by responding to the opening / closing time of the switch means 6, so that the air conditioner can be used. If the load amount varies, it is necessary to perform a plurality of times of switching. in this way,
Since the opening / closing time of the switch means 6 can be finely changed according to the load amount of the load 7, it is possible to reduce harmonics of the input current while always maintaining a high power factor. Further, since the switching means 6 is opened and closed several times in a half cycle of the power supply, low frequency switching can be realized, switching loss can be reduced, efficiency can be improved, and cost reduction can be realized in terms of noise countermeasures. Further, in the high frequency switching, the necessary feedback is not necessary since the feedback is the low frequency switching, and the control is simplified, so that further cost reduction can be realized.

On the contrary, if the switching is performed only once every half cycle of the power source, the inductance value in the reactor becomes large in order to suppress the harmonics, and if the inductance value becomes large, the heat generation in the reactor also becomes large. ,
By performing the switching several times in the half cycle of the power source, it is possible to reduce the inductance value of the reactor and to reduce the heat generation as compared with the switching performed only once in the half cycle of the power source. Further, as the inductance value becomes smaller, the outer shape of the reactor also becomes smaller, so that the reactor can be downsized.

Embodiment 2. FIG. 8 is a block diagram showing a DC power supply device according to Embodiment 2 of the present invention. In the figure, the same components as those in the first embodiment of the present invention are designated by the same reference numerals, and the description of the duplicate components will be omitted. Reference numeral 12 is an inverter connected in parallel to the smoothing capacitor 4, 13 is an inverter control unit that controls the inverter 12, and 14 is a load that receives information on an operation mode command and inverter frequency from the inverter control unit 13 and estimates a load amount applied to the inverter 12. It is a quantity estimation means. The inverter 12 is a driving portion for driving the motor, and the motor is connected to the inverter 12. This motor is, for example, a compressor motor used in an air conditioner.

The operation of the DC power supply device according to the second embodiment of the present invention shown in FIG. 8 will be described. In the air conditioner using the inverter 12, the required rotation speed and rotation force are set depending on the operating state. Further, since the operating speed of the inverter 12 is determined by the inverter frequency, the set value of the rotational force required for the operation can be known from the operating state and the operating speed. Here, the motor output P
Is determined by the product of the rotational speed n and the rotational force T, and P = k
It is represented by × n × T, and k is a coefficient. The motor output P of the motor connected to the inverter 12 is controlled by the inverter control unit 13 so as to be output according to the load amount, so the motor output P can be regarded as the load amount. Therefore, if you know the operating condition and the inverter frequency,
The load can be estimated by calculation. Therefore,
The inverter control unit 13 transmits the operation mode and the inverter frequency to the load amount estimating unit 14, and the load amount estimating unit 1
The load amount can be estimated by calculating in 4.

By the load amount estimating means 14 opening and closing the switch means 6 in accordance with the estimated load amount,
It is possible to operate the air conditioner equipped with the inverter without providing the load amount detecting means, with the same effect as that of the invention shown in the first embodiment of the invention. This means that in an air conditioner equipped with an inverter, the load amount can be detected without detecting the load amount in the existing control unit, so that the cost can be reduced as compared with the invention shown in the first embodiment of the invention. Is.

Embodiment 3. 9 is a block diagram showing a DC power supply device according to a third embodiment of the present invention. In the figure, the same components as those in the first embodiment of the present invention are designated by the same reference numerals, and the description of the duplicate components will be omitted. Reference numeral 15 is an output current detecting means for detecting the output current flowing through the load 7, and 16 is a load amount calculating means for calculating the load amount of the load 7 from the output current detected by the output current detecting means 15.

The operation of the DC power supply device according to the third embodiment of the present invention shown in FIG. 9 will be described. The output current flowing from the load 7 flows in proportion to the load amount of the load 7. This is because the torque T corresponding to the flowing current is generated in the motor. Therefore, the output current is detected, and the load amount is calculated from the detected current value. That is, the load amount is approximated by output current × DC bus voltage × power factor, and the DC bus voltage and the power factor during operation are almost constant. Therefore, the load amount can be obtained by detecting the output current. . Therefore, the output current detection unit 15 detects the output current flowing through the load 7, and the load amount calculation unit 16 outputs the load amount of the load 7 calculated from the output current detected by the output current detection unit 15 to the selection unit 11. Then, the first embodiment of the present invention will be described.
Similarly, the selection means 11 selects the opening / closing time according to the load amount from the storage means 9 and informs the control means 8, and the control means 8 causes the switch means 6 to switch at an appropriate opening / closing time according to the load 7. .

The third embodiment of the present invention shown in FIG. 9 has an existing structure by providing an output current detecting means 15 and a load amount calculating means 16 instead of the load amount detecting means 10 of the first embodiment. Since the load amount can be detected by using the output current detection unit and the load amount calculation unit for performing a simple calculation, the cost can be reduced as compared with that shown in the first embodiment of the invention. Furthermore, it becomes possible to protect circuit elements and the like due to excess output current.

Fourth Embodiment FIG. 10 is a block diagram showing a DC power supply device according to Embodiment 4 of the present invention. In the figure, the same components as those in the first embodiment of the present invention are designated by the same reference numerals, and the description of the duplicate components will be omitted. Reference numeral 17 is an output voltage detecting means for detecting the output voltage flowing through the load 7, and 18 is a load amount calculating means for calculating the load amount of the load 7 from the output voltage detected by the output voltage detecting means 17.

The operation of the DC power supply device according to the fourth embodiment of the present invention shown in FIG. 10 will be described. In the fourth embodiment as well, as in the first embodiment, the switch means 6 is operated only a few times in the half cycle of the power supply, but the timing of the switch of the switch means 6 is set so that this operation does not operate in the boost region. Is set, the DC bus voltage drops due to the resistance component existing in the DC reactor 3. In this case, the more the load amount of the load 7 increases, the larger the voltage drop, and conversely, the voltage drop does not occur when the load amount of the load 7 is absent.

Therefore, if the DC bus voltage when there is no load on the load 7 is used as a reference, the load can be estimated from the voltage drop from the reference voltage. For example, assuming that the reference voltage is 282V and the load amount is 80% of the maximum rating, the output voltage causes a voltage drop of about 20V, so the voltage value detected by the output voltage detection means 17 is 262V. it is conceivable that. In other words, when the detected voltage value of the output voltage means 16 is 262V, it can be estimated that the load amount is about 80% of the maximum rating. Therefore, the output voltage detection means 17 detects the output voltage applied to the load 7, and the load amount calculation means 18 outputs the load amount of the load 7 calculated from the output voltage detected by the output voltage detection means 17 to the selection means 11. To do. Then, similarly to the first embodiment of the present invention, the selection unit 11 selects the opening / closing time according to the load amount from the storage unit 9 and informs the control unit 8, and the control unit 8 sets the switch unit 6 to the load 7. Switch operation at an appropriate opening / closing time according to the operation.

The fourth embodiment of the present invention shown in FIG. 10 has an existing structure in which an output voltage detecting means 16 and a load amount calculating means 17 are provided instead of the load amount detecting means 10 of the first embodiment. Since the load amount can be detected by using the output voltage detection unit and the load amount calculation unit for performing a simple calculation, the cost can be reduced as compared with that shown in the first embodiment of the invention. Further, although the existing overvoltage detecting means is adapted only to the output voltage excess, the output voltage detecting means 16 and the load amount calculating means 17 can protect the overcurrent due to the low voltage, the malfunction, and the like. .

Embodiment 5. 11 is a block diagram showing a DC power supply device according to a fifth embodiment of the present invention. In the figure, the same components as those in the first embodiment of the present invention are designated by the same reference numerals, and the description of the duplicate components will be omitted. Reference numeral 19 is a temperature rise detecting means for detecting a temperature rise of the switch means 6, and 20 is a load amount calculating means for calculating the load amount of the load 7 from the temperature rise value detected by the temperature rise detecting means 19.

The operation of the DC power supply device according to the fifth embodiment of the present invention shown in FIG. 10 will be described. First, before the switch means 6 starts its operation, the temperature rise detecting means 19 detects the ambient temperature. After that, when the switch means 6 starts to operate, the temperature rise of the switch means 6 is detected. The temperature of the switch means 6 rises because of switching loss in the switch means 6. When the switching loss is Pc, the current flowing through the switching element is I, and the on-resistance of the switching element is Ron, the switching loss Pc can be expressed as Pc = I ² × Ron. In addition, the case temperature Tc of the switching element and the ambient temperature Tn
Using, the temperature rise value Tα can be approximated by Tα = Tc-Tn. Here, regarding the relationship between the temperature rise value Tα and the switching loss Pc, the switching loss P
c can be approximated by Pc = k × Tα (k is a coefficient).

Therefore, Pc = k × Tα = k × (Tc-T
Since n) = I ² × Ron, I can be obtained by knowing Tc, Tn, Ron, and k. Where Ron, k
Is a value determined by the switching element used, so I is the temperature rise value T found by detecting Tc and Tn.
It becomes possible to obtain from α. The ambient temperature Tn is almost the same as the temperature of the sufficiently cooled switching element before switching is started. I is a current value when the switch means is turned on, but it is a value that changes depending on the load amount. If the current value flowing through the switch means is known, the load amount can be estimated from the current value as described above. . From this, the value of the current flowing through the switch means 6 is obtained from the temperature rise value of the switch means 6, the load amount is estimated from the current value, and the control means 8 controls the switch means 6 to operate.

Therefore, the temperature rise detection means 19 detects the temperature rise of the switch means 6, the load amount calculation means 20 first calculates the current value from the temperature rise value detected by the temperature rise detection means 19, and then the The load amount of the load 7 is calculated from the current value, and the calculated load amount of the load 7 is output to the selection means 11. Then, similarly to the first embodiment of the present invention, the selection unit 11 selects the opening / closing time according to the load amount from the storage unit 9 and informs the control unit 8, and the control unit 8 sets the switch unit 6 to the load 7. Switch operation at an appropriate opening / closing time according to the operation.

The fifth embodiment of the present invention shown in FIG. 11 has a structure in which a temperature rise detecting means 19 and a load amount calculating means 20 are provided in place of the load amount detecting means 10 of the first embodiment. The same operation as described in the first embodiment can be performed. Further, the temperature rise detecting means 1
By providing the switch 9, it is possible to protect the temperature of the switch device 6, and it is also possible to prevent deterioration and damage of the switch element used in the switch device 6.

Sixth Embodiment 12 is a block diagram showing a DC power supply device according to a sixth embodiment of the present invention. In the figure, the same components as those in the first embodiment of the present invention are designated by the same reference numerals, and the description of the duplicate components will be omitted. The number 21 is set to the number of times the switch means 6 is opened and closed in a half cycle of the power supply. The load amount detected by the load amount detection means 10 and the switch stored in the storage means 9 for the remaining number of times after the first time. It is a calculating means for calculating the open / close time of the switch means 6 not stored from the open / close time of the means 6.

The operation of the DC power supply device according to the fifth embodiment of the present invention shown in FIG. 10 will be described. The storage means 9 stores the data of the delay time Tsw1 from the zero cross point of the AC power supply 1 to the closing of the switch means 6 and the closing time Ton1 of closing the switch means 6 according to the load amount. The load amount detection means 10 detects the load amount, and the selection means 11 appropriately selects Tsw1 and Ton1 from the storage means 9 according to the detected load amount, and the selected Tsw1 and Ton1 are controlled by the control means 8 and the calculation means. Tell 21. Regarding the opening and closing of the switch means 6 for the first time in the power supply half cycle, the control means 8 selects Tsw1 and Tsw selected by the selection means 11.
The switch means 6 is opened and closed by on1. Then, regarding the opening and closing of the switch means 6 after the first time in the power source half cycle, the opening and closing time calculated by the calculating means 21 is output to the control means 8 via the selecting means 11, and the control means 8 uses the calculated opening and closing time. The switch means 6 is opened and closed.

Now, a method of calculating the remaining opening / closing time by the calculating means 21 will be described. For example, in the case of a DC power supply control device for an air conditioner for domestic use, the calculation is performed as follows. Assuming that the load amount is α kW, the inductance value of the reactor is L [mH], the second delay time until the switch means 6 is closed is Tsw2, and the time during which the switch means 6 is closed for the second time is Ton2, Tsw2 = (L -T
It is expressed by two expressions of sw1) / α and Ton2 = Ton1 / α, and the opening / closing time of the switch means 6 for the second time is obtained by the above calculation method. When opening and closing three times or more, Tsw3 = Tsw2 / α, Ton3 = T
It is calculated by the two equations of on2 / α. Note that the above two formulas are created from experience such as experiments and simulations.

As described above, the second and subsequent opening / closing times can be sequentially calculated based on the previous one. Therefore, even if the number of times of opening / closing of the switch means 6 increases, the calculating means 21 is used. Without increasing the storage capacity of the storage means 9,
It can be opened and closed several times in a half cycle of the power supply. It is assumed that the calculating means 21 itself stores the opening and closing times obtained after the second time. Further, the storage amount required for the number of operations of the switch unit 6 in the storage unit 9 can be one storage amount. Therefore, the greater the number of times of opening and closing, the greater the degree of decrease in the total storage amount. Therefore, the size of the memory element can be reduced. Also, since the total memory capacity is reduced, it is possible to store a large amount of switching time according to the load quantity when using elements with the same memory capacity.
Fine control of high power factor and harmonic suppression is possible.

Embodiment 7. 13 is a block diagram showing a DC power supply device according to a seventh embodiment of the present invention. In the figure, the same components as those in the first embodiment of the present invention are designated by the same reference numerals, and the description of the duplicate components will be omitted. Reference numeral 22 is a power supply means connected in parallel to the smoothing capacitor 4, 23 is a power supply control section for controlling the power supply means 22, and is a stop for stopping the control section itself based on a stop signal generated by detecting an abnormality at the time of abnormality. It has a function part 23a. Further, the control means 8 of this embodiment has a stop function part 8a that stops the control part itself based on a stop signal generated by detecting an abnormality at the time of abnormality. The stop function part 8a of the control means 8 and the stop function part 23a of the power supply control part 23 are connected by a signal line 24, and the power supply control part 23 has the stop function part 23a of the control means 8. The control means 8 is stopped by receiving a stop signal from the power supply control unit 8a.
It is configured to interlock so as to stop upon receiving a stop signal from a. The power supply means 22 and the power supply controller 23 constitute a power supply device, and the power supply device includes, for example, an inverter.

The operation of the DC power supply device according to the seventh embodiment of the present invention shown in FIG. 13 will be described. In FIG. 13, when the switch means 6 is operating while the power supply means 22 is stopped, a steep pulsed current flows through the switch means 6 and energy is stored in the DC reactor 3. However, since the power supply means 22 is stopped, the energy of the smoothing capacitor 4 is not transmitted to the power supply means 22. Therefore, the smoothing capacitor 4 cannot be discharged, and energy is still stored, and the smoothing capacitor 4 does not shift to the discharging state. Since the smoothing capacitor 4 serving as a pan for receiving the energy of the DC reactor 3 stores energy, the energy stored in the DC reactor 3 is not released from the DC reactor 3 but only accumulated. Therefore, the voltage component in the DC reactor 3 is added to the DC bus voltage, and the DC bus voltage rises. The boosting of the DC bus voltage causes deterioration of the smoothing capacitor 4, and the steep pulse-like current flow into the switch means 6 leads to failure or damage of the switch means 6.

If the switch means 6 is not in operation while the power supply means 22 is in operation, the operation is in a state where the power factor is lowered. Since output power = power factor × output voltage × output current is approximated, in the operation with the power factor reduced, the output current increases when the same power is output. This is a DC bus voltage smoothing capacitor 4
This is because it is determined by the capacity of and becomes almost constant. Therefore, a current larger than the expected current value will flow through the power supply means 22. The increase in the output current caused by the decrease in the power factor causes not only the power supply means 22 but also the failure of the full-wave rectifier circuit 2, the DC reactor 3, the reverse current blocking diode 5, the smoothing capacitor 4, etc. in the current path. Become. Therefore, operating only one of the DC power supply control device including the switch unit 6 and the power supply unit including the power supply unit 22 and the power supply control unit 23 causes a failure. The seventh embodiment of the present invention is made to solve such a problem.

For example, in the power supply device, when the stop function part 23a of the power supply control part 23 detects an abnormality and stops the control part itself based on the stop signal, the control means 8 of the direct current power supply control device outputs the error. The stop function part 8a receives the stop signal from the stop function part 23a of the power supply control part 23 and stops the control means itself. When the stop function unit 8a of the control unit 8 of the DC power supply control device detects an abnormality and stops the control unit itself based on the stop signal, the stop function unit 23a of the power supply control unit 23 of the power supply device is Control means 8
In response to the stop signal from the stop function unit 8a, the control unit itself is stopped.

As described above, the power supply device and the DC power supply control device operate independently, but the DC power supply control device is always stopped when the power supply device is stopped, and the power supply device is always stopped when the DC power supply control device is stopped. By stopping the operation, the failure of the parts forming the circuit is prevented. Also,
By eliminating the operation of only one of the power supply device and the DC power supply control device, it is possible to provide a highly reliable DC power supply device. Further, in the above embodiment, the power supply means 22 is connected in parallel to the smoothing capacitor 4, and the power supply means 22 is applied to the DC power supply device controlled by the power supply control unit 23. However, the embodiment shown in FIG. In the DC power supply device of the second aspect, the inverter control unit 13
Has a stop function unit for stopping the control unit itself on the basis of a stop signal generated when an abnormality is detected by the control unit 8
Has a stop function unit for stopping the control means itself based on a stop signal generated by detecting an abnormality when an abnormality occurs, and the stop function unit of the inverter control unit 13 and the stop function unit of the control unit 8 are connected by a signal line. It goes without saying that, by doing so, the same operational effects as those of the seventh embodiment of the present invention can be obtained.

Embodiment 8. FIG. 14 is a block diagram showing a DC power supply device according to an eighth embodiment of the present invention. In the figure, the same configurations as those of the seventh embodiment of the present invention are designated by the same reference numerals, and the description of the duplicated configurations is omitted. 25 is a smoothing capacitor 4 and a switch means 6
When a current flowing from the DC to the DC bus is detected and the current exceeds a preset value, a command is issued to the power supply control unit 20 to stop the operation of the power supply means, and the detected current is It is an overcurrent detection means for issuing a command to the control means 8 to stop the switch means 6 when a certain set value set near the peak value is exceeded.

The operation of the DC power supply device according to the eighth embodiment of the present invention shown in FIG. 14 will be described. In FIG. 14, when a current that is considerably larger than a normal current flows on the bus bar due to a malfunction, the switch means 6 of the DC power supply control device and the power supply means 19 of the power supply device are operated in order to protect the product. Need to stop. Either the switch means 6 or the power supply means 22 is provided with an overcurrent detection means, or either one is provided with an overcurrent detection means, and an instruction to stop the operation is issued from the one provided with the overcurrent detection means. It is necessary to adopt a configuration in which the current detection means is not provided. In the former case, two overcurrent detecting means are required, and in the latter case, it is not clear which is the cause of the overcurrent occurrence.

In the eighth embodiment of the present invention, the overcurrent protection of the switch means 6 and the power supply means 19 is realized by one overcurrent detection means, and the overcurrent generation source is specified. It is a thing. In FIG. 14, when an overcurrent flows due to a malfunction of the switch means 6, a steep current flows through the overcurrent detection means 24 from the switch means 6 to the negative side of the full-wave rectifier circuit 2. On the contrary, when the load 7 supplied with power from the power supply means 22 is in an overload state, the load 7 consumes a larger current value than the current value flowing in the normal state, so that the current value flowing in the entire circuit increases. To do. Further, even when the power supply means 22 has a short circuit failure, the peak current will flow, but the flowing direction is opposite to the peak current due to the inconvenience of the switch means 6 of the DC power supply control device, and the power is not supplied. The current flows from the supply means 22 to the positive electrode side of the full-wave rectification circuit 2 through the negative electrode side of the full-wave rectification circuit 2, the smoothing capacitor 4, and the reverse current is blocked by the diode 5, so that the current flows to the power supply means 19 so as to be regenerated. .

In this way, it is possible to detect from the flow of the bus current that there is an overcurrent due to a malfunction of the switch means 6 or the power supply means 22, and it is possible to identify the device that has caused the overcurrent. Further, since it is possible to recognize the overcurrent due to the overload, it is possible to prevent the failure of the DC power supply and the power supply apparatus and to specify that the DC power supply control apparatus and the power supply apparatus are not the failure.

Now, the operations of the control means 8 and the power supply control section 20 after detecting the overcurrent will be described. First, when a steep current near the peak value flows, the overcurrent detection means 25 causes the control means 8 to stop the switch means 6 when the steep current is larger than the second set reference value. The control means stop signal is issued to the control means 8, and the control means 8 which has received the control means stop signal stops the switch means 6. This is because if the DC power supply controller is out of order,
This is because all parts after the DC power supply may be damaged. If the direction in which the steep overcurrent flows is from the negative side of the full-wave rectifier 2 to the negative side of the smoothing capacitor 4, there is a fault in the power supply device, and from the negative side of the smoothing capacitor 4 to the full-wave rectifier circuit 2. If it flows to the negative electrode side, it is found that the DC power supply control device has failed. Since it is not preferable to operate in a failure state, the control means 8 issues a stop command signal to the power supply control section 23 so as to stop the power supply means 22 after a predetermined time has passed, and outputs the stop command signal. The received power supply control unit 23 stops the power supply means 22, stops the operation of the power supply device, and prevents the failure of other components.

When the overcurrent detecting means 22 is not a steep current and the cause of the overcurrent is an overload and the current increases to some extent and works, the overcurrent detecting means 25 detects that the increased current is the first. When the value is larger than the set reference value of, the control unit stop signal is output to the power supply control unit 23 so as to stop the power supply unit 22, and the power supply control unit 23 receiving the control unit stop signal causes the power supply unit 22 to operate. Stop. By stopping the operation of the power supply means 22, damage to the load supplied with power from the electrode supply means 22 and damage to the power supply device are prevented. Then, the power supply control unit 23 outputs a stop command signal to the control means 8 so as to stop the switch means 6 after a lapse of a predetermined time, and the control means 8 receiving the stop command signal stops the switch means 6 and other parts. It prevents the breakdown of the. In this way, both the DC power supply control device and the power supply device are stopped, and after a certain period of time, the operation is restarted and if no overcurrent occurs, it is a temporary overload state or input fluctuation. Since it is a temporary overcurrent caused by, there is no problem even if the operation is restarted.

Further, the operation of only one of them causes a failure or deterioration as described in the above embodiment. Therefore, when a steep overcurrent or a rise in overcurrent is detected, there is no problem even if the operations of the DC power supply device and the power supply device are stopped at the same time. If both of them are stopped at the same time after the overcurrent is detected, it is not known which is the cause, and whether it is a temporary overcurrent stop due to input and output fluctuations or a stop due to an overcurrent due to a failure. There is a risk that it will not be possible to determine what is happening. So, stop only one side,
As soon as the cause of the overcurrent has been identified, the other device is also stopped to prevent deterioration and breakdown due to the overcurrent.

By detecting the direction of the peak current by the overcurrent detecting means 25, it is possible to specify whether the DC power supply control device or the power supply device is the source of the overcurrent, and also detect the rise of the current. As a result, it is possible to protect the load in the overload state, and it is possible to protect the two devices and the load with one overcurrent detecting means 24, which contributes to downsizing of the circuit configuration and cost reduction. It is a thing. In the above embodiment, the overcurrent detection means 25 detects the current flowing from the smoothing capacitor 4 and the switch means 6 to the DC bus, and supplies the power when the current exceeds the set first setting reference value. Although an instruction is issued to the control unit 23 to stop the operation of the power supply unit 22, the average value of the current detected by incorporating an integrator or a constant time constant circuit is the first setting reference value. When it exceeds, the power supply control unit 23 may be instructed to stop the operation of the power supply unit 22. In this case, it is possible to prevent a malfunction due to a transient increase in current.

Further, in the above-mentioned embodiment, the power supply means 22 is connected in parallel to the smoothing capacitor 4, and the power supply means 22 is controlled by the power supply control section 23. Also in the DC power supply device of the second embodiment shown in FIG. 3, the inverter control unit 13 has a stop function unit that stops the control unit itself based on a stop signal generated when an abnormality is detected and the control unit 8 is abnormal. A stop function unit for stopping the control unit itself based on a stop signal generated when an abnormality is detected is sometimes provided, and the stop function unit of the inverter control unit 13 and the stop function unit of the control unit 8 are connected by a signal line, When the current flowing from the smoothing capacitor 4 and the switch means 6 to the DC bus is detected and the current exceeds a certain set value, the power supply controller 20
To the control means 8 when the detected current exceeds a certain set value near the peak value, the control means 8 is commanded to stop the switch means 6. It goes without saying that the provision of the overcurrent detection means provides the same operational effect as the eighth embodiment of the present invention.

[0065]

According to the present invention, the power factor of the input current can be improved and the harmonics can be reduced.

[Brief description of drawings]

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

FIG. 2 is an operation input current waveform diagram when the switch means of the same DC power supply device is not operating.

FIG. 3 is an operation input current waveform diagram when the switch means of the same DC power supply device is operating.

FIG. 4 is a flowchart showing a method of setting a reactor value and an opening / closing time.

FIG. 5 is a graph showing a comparison between a harmonic generation amount and a regulation value when an operation simulation is performed with the configuration of the same DC power supply device.

FIG. 6 is a graph showing a comparison between a harmonic generation amount and a regulation value when an operation simulation of different outputs is performed in the configuration of the same DC power supply device.

FIG. 7 is a graph showing a comparison between a harmonic generation amount and a regulation value when the switch means is operated once in a power source half cycle in the configuration of the same DC power supply device and simulated.

FIG. 8 is a block diagram showing a configuration of a DC power supply device according to a second embodiment of the present invention.

FIG. 9 is a block diagram showing a configuration of a DC power supply device according to a third embodiment of the present invention.

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

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

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

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

FIG. 14 is a block diagram showing a configuration of a DC power supply device according to an eighth embodiment of the present invention.

FIG. 15 is a block diagram showing a configuration of a conventional DC power supply device.

[Explanation of symbols] 1 AC power supply, 2 full-wave rectifier, 3 DC reactor,
5 backflow prevention diode, 6 switch means, 7 load, 8 control means, 9 storage means, 10 load amount detection means, 11 selection means.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-8-19259 (JP, A) JP-A-3-178563 (JP, A) JP-A-9-247943 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H02M 3/155 H02M 7/12

Claims (6)

(57) [Claims] 1. A rectifier circuit for rectifying a voltage of an AC power supply, a smoothing capacitor for smoothing an output voltage from the rectifier circuit, a switch means arranged on the AC power supply side of the smoothing capacitor, and a power supply for the switch means. Side reactor and the amount of harmonics of the input current below the regulation value for each load amount in advance.
Opening and closing time of the switch means for each load amount
Corresponding to the storage means for correspondingly storing, the load amount detecting means for detecting the load amount of the load connected in parallel to the smoothing capacitor, and the load amount detected by the load amount detecting means.
Select the opening / closing time of the switch means from the storage means
Selection means for, the synchronization with the power source period of the AC power supply at least two times the power supply half cycle, the off time selected by the selection means
An air conditioner characterized in that a direct current power supply device having a control means for controlling opening and closing of the switch means in between is a direct current power supply device of a compressor. 2. The diode for preventing backflow from the smoothing capacitor to the switch means when the switching means switches between the DC bus voltages on the output side of the rectifier circuit. Air conditioner described. 3. A rectifier circuit for rectifying the voltage of an AC power supply, a smoothing capacitor for smoothing an output voltage from the rectifier circuit, a switch means arranged on the AC power supply side of the smoothing capacitor, and a power supply for the switch means. Side reactor, an inverter connected in parallel to the smoothing capacitor, an operating mode of the air conditioner and an inverter frequency
Switch so that the amount of harmonics of the input current is below the regulation value.
The opening and closing time of the air conditioner,
And storage means for storing the data corresponding to each inverter frequency
And an inverter control unit that drives and controls the inverter at a desired inverter frequency, and corresponds to the operation mode and inverter frequency of the air conditioner
The open / close time of the switch means is selected from the storage means.
The selecting means to be selected, and the opening / closing operation selected by the selecting means at least twice in a half cycle of the power source in synchronization with the power source cycle of the AC power source.
An air conditioner characterized in that a direct current power supply device having a control means for controlling opening and closing of the switch means in between is a direct current power supply device of a compressor. 4. The control means opens and closes the switch means at least twice during a period in which an input current generated by the rectifier circuit and the smoothing capacitor from the AC power supply does not flow. The air conditioner according to 2 or 3. 5. The air conditioner according to claim 1, wherein the control means controls opening / closing of the switch means at intervals at which the input current due to opening / closing of the switch means is continuous. 6. The load amount detecting means is obtained by a compressor.
The load amount detected is detected.
2. The air conditioner described in 2.