JP2005229792A - Power supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress power supply higher harmonic waves, by realizing the stabilization of current control by maintaining a load output voltage at a constant level, in a power supply device having a power factor improving means. <P>SOLUTION: When a voltage of a load 4 is obtained with a step-up chopper circuit 3 by converting an input power supply 1 into a DC voltage, a power factor is improved, by switching a switching element 3c of the step-up chopper circuit 3 and short circuiting via a step-up chalk coil 3a. A no-load output voltage is detected by a voltage-dividing resistor circuit 12 for detecting a load voltage and an A/D converting means of a control part 13 at its current control. A prescribed ratio value is multiplied to the no-load output voltage. The voltage deviation between the no-load output voltage, to which the prescribed ratio value is multiplied, and the output voltage with a load is calculated. Voltage control, corresponding to an amount of the voltage deviation, is added so as to maintain the no-load output voltage and the output voltage with a load at a prescribed ratio. The output voltage is maintained at a constant level, regardless of the resistance variations of the voltage-dividing resistor circuit 12 and variations of a reference voltage in the A/D conversion means. Consequently, stabilization of the current control can be realized. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a control technology for a power supply device used for an air conditioner or the like, and more specifically, a power supply device having a boost chopper circuit including a reactor to improve power factor improvement and stabilization of harmonic current suppression function. It relates to control technology.

  As an example of this type of power supply device, as shown in FIG. 10, an input power supply (commercial power supply) 1 is full-wave rectified by a rectifier circuit 2, and this AC / DC converted voltage is used as a boost chopper circuit (power factor improving means). ) The power factor of the power supply is improved by passing 3 and the harmonic current is suppressed.

  In this example, the boost chopper circuit 3 includes a boost choke coil (reactor) 3a connected in series to the positive terminal side of the rectifier circuit 2, a reverse blocking diode 3b connected in series to the boost choke coil 3a, and a boost choke coil 3a. A switching element (for example, IGBT; insulated gate transistor) 3c connected between the reverse blocking diode 3b on the negative terminal side of the rectifier circuit 2 and a smoothing capacitor 3d for smoothing the output voltage are provided.

  The step-up chopper circuit 3 operates by switching the step-up choke coil 3a by the switching element 3c and short-circuiting to the negative terminal side, while supplying the switched voltage from the reverse blocking diode 3b to the smoothing capacitor 3d. And As the load 4, for example, when applied to a compressor motor of an air conditioner, an inverter circuit 4a and a motor 4b can be assumed.

  As a power supply device having such a step-up chopper circuit 3, there is, for example, Patent Document 1 by the present applicant. When converting an AC power source into a DC voltage to obtain a load voltage, the converted voltage is at least a reactor (step-up). The power factor is improved by short-circuiting the choke coil 3a).

  This power supply device controls a switching element 3c based on a current sensor 5 for detecting an input current Ii of the boost chopper circuit 3 and its detected current value, an input voltage Vi and an output voltage Vo of the boost chopper circuit 3. And a drive unit 7 that drives the switching element 3 c by a signal from the control unit 6.

  The control unit 6 switches the switching element 3c of the boost chopper circuit 3 and turns on / off the switching element 3c based on the comparison result between the input current and the sine wave input current reference signal, thereby outputting the output voltage of the boost chopper circuit 3 Let Vo be the voltage of the load.

  At this time, as shown in FIG. 11, the deviation between the output voltage command value and the detected output voltage Vo is calculated by the calculating means 6a, and the amplitude value of the input current reference signal Ir is calculated by the current reference signal amplitude creating means 6b based on this calculated deviation. (A so-called reference sinusoidal amplitude value) is created.

  The multiplication of the created amplitude value and the detection input voltage Vi is performed by the multiplication means 6c, and hysteresis is created by the hysteresis comparator 6d based on the input current reference signal (current command value) and the current detection value Ii obtained as a result of the multiplication. Thus, an upper limit value and a lower limit value of the input current are created by this hysteresis, and current control for switching the switching element 3c is performed so that the input current Ii falls within the range of the upper limit value and the lower limit value. .

  In Patent Document 2, the zero cross of the AC power supply 1 is detected by the power supply phase detection circuit 8, and a predetermined period from the predetermined zero cross to the zero cross is generated by the switching operation prohibition time creating means 6e. The output of hysteresis is prohibited by the AND circuit 6f by the creation signal.

  As a result, as shown in FIGS. 12 and 13, since switching of the switching element 3c is prohibited only during the prohibited period, the input current is forced to be zero at the zero cross point of the input AC power supply, and the input near the zero cross point is input. The AC waveform is improved (sinusoidal), and higher harmonic current can be reduced.

JP 2002-112573 A Japanese Patent Laid-Open No. 2004-7880

  By the way, in the switching operation, the input current tends to increase in a section where the input voltage is higher than the output DC voltage (Vi ≧ Vo; near the peak area of the input current), and therefore the switching element 3c is almost turned off. (See FIGS. 12 and 13).

  Thus, it can be said that the output DC voltage Vo is an important parameter for the input current waveform and the harmonic current. Therefore, if there is a variation in the output DC voltage Vo, the input current by the current control will be affected, and the harmonic current characteristics and the power factor improvement characteristics will differ depending on the device on which the power supply device is mounted. There arises a problem that the adaptability of the power supply device is lowered.

  In the power supply device described above, it is preferable to perform voltage feedback control by software of a microcomputer from the viewpoint of cost, etc., so that a voltage dividing resistor circuit including a series connected resistor is provided to detect the output DC voltage Vo. The output of the voltage dividing resistor circuit is A / D converted.

  However, an error occurs in detection of the output DC voltage Vo due to variations in resistance values of the resistance elements used in the voltage dividing resistor circuit and variations in the A / D converter reference voltage AVR necessary for A / D conversion. Since the output DC voltage Vo including this error is fed back, the load voltage command value may not be output accurately.

  Generally, the variation of the resistance element is about ± 4 to 6%, but for example, when detecting the output DC voltage Vo of about 300V, it becomes about ± 12 to 18V, and such a large error is caused in the voltage feedback system. If included, current control may not be stable, and power harmonic regulations may not be cleared.

  In addition, the above device variations greatly affect the input current waveform, and the input current waveform is similar to the input voltage waveform due to a decrease in the power supply voltage due to an increase in the input current or an increase or decrease in the power supply voltage due to the influence of other connected devices. It becomes impossible to keep the shape and affects the stability of current control.

  In order to solve the above-described problem, the invention according to claim 1 improves the power factor by short-circuiting the AC power source through a reactor when the AC power source is converted into a DC voltage by a rectifying means to obtain a load voltage. And switching the switching element of the power factor improving means including the reactor, and turning on and off the switching element according to a comparison result between the input current and the input current reference signal of the input AC power supply voltage waveform. While the output voltage of the power factor improving means is used as the load voltage, the load detecting means detects the no-load output voltage and the loaded output voltage during the current control, and the ratio between the no-load output voltage and the loaded output voltage is The voltage control is performed so as to be a predetermined value.

  The invention described in the first aspect includes the aspects described in the second to fourth aspects. That is, according to a second aspect of the present invention, the predetermined ratio of the load output voltage to the no-load output voltage is a value obtained in advance according to the load state.

  According to a third aspect of the present invention, the predetermined value is a ratio of an input voltage when there is a load and when there is no load. In the fourth aspect, a rectified average value or an effective value is used instead of the input voltage. It is characterized by use.

  In order to solve the above-described problem, the invention according to claim 5 is directed to a power factor by short-circuiting the AC power source through a reactor when the AC power source is converted into a DC voltage by a rectifying means to obtain a load voltage. In the power supply device for improving the power factor, the switching element of the power factor improving means including the reactor is switched, and the switching element is turned on / off based on the comparison result between the input current and the input current reference signal of the input AC power supply voltage waveform. The load voltage is used as the output voltage of the power factor improving means, while the load detecting means detects the no-load output voltage and the loaded output voltage when the current is controlled. The voltage control is performed so that the difference becomes a predetermined value.

  The invention according to the fifth aspect includes the aspects of the sixth to ninth aspects. That is, in claim 6, when performing voltage control so that a difference between the no-load output voltage and the load output voltage becomes a predetermined value, a predetermined value is subtracted from the no-load output voltage as a load voltage command value. It is characterized by using the following value.

  According to a seventh aspect of the present invention, there is provided means for detecting an input AC power supply voltage, and when the AC detection voltage becomes larger than the beginning of the control, the load voltage command value is increased, and the AC detection voltage starts the control When it becomes smaller than the initial value, the load voltage command value is reduced. This claim 7 also depends on claim 1.

  In claim 8, when calculating the load voltage command value by subtracting a predetermined value from the no-load output voltage, the no-load output voltage and the no-load AC power supply voltage It is characterized by multiplying the ratio with the voltage.

  According to a ninth aspect of the present invention, instead of the no-load output voltage used for calculating the load voltage command value, a value obtained by adding a predicted value of a voltage drop caused by load driving from the load output voltage is used. It is said.

  Further, in the inventions according to claims 1 and 5, as described in claim 10, a rectified average value or an effective value can be used instead of the no-load output voltage and the load output voltage. Further, as described in claim 11, it is preferable to determine a no-load state by a no-load determination unit and store and update a detection value at the time of no-load.

  According to the first aspect of the present invention, voltage control is performed so that the ratio between the no-load output voltage and the loaded output voltage becomes a predetermined value, so that the resistance value variation and A Voltage control can be performed without being affected by variations in the reference voltage in the / D conversion, and the load output voltage is kept constant, so that the current control can be stabilized and the harmonic current can be reduced. The effect is played.

  According to the fifth aspect of the present invention, the voltage control is performed so that the difference between the no-load output voltage and the loaded output voltage becomes a predetermined value. Therefore, when applied to an air conditioner, for example, it is possible to simultaneously perform PFC (Power Factor Correction) control and compressor control with a single one-chip microcomputer.

  The power supply apparatus according to the first embodiment of the present invention (corresponding to claim 1) is a voltage dividing resistor for detecting the output voltage Vo (t) of the boost chopper circuit when controlling the boost chopper circuit including at least the reactor. While detecting a no-load output voltage Vo (0) using a circuit, LPF and A / D converter, a load voltage command value A × Vo (0) obtained by multiplying the no-load output voltage Vo (0) by a predetermined ratio value. ) And the load output voltage Vo (t), the voltage control corresponding to the voltage deviation Ve is added to the current control, and the load-loaded voltage is kept at a predetermined ratio with respect to the no-load voltage. Thus, the load output voltage is kept constant regardless of variations in the voltage dividing resistor and the A / D converter reference voltage AVR.

  That is, according to the present invention, the ratio Vo (t) / Vo (0) between the load output voltage and the no-load output voltage of the boost chopper circuit is a value that does not depend on the variation of the voltage dividing resistor and the reference voltage AVR of the A / D converter. Become.

  Therefore, if the ratio value A (= Vo (t) / Vo (0)) is obtained by measuring with a predetermined circuit, the value can be used in any model regardless of variations. Therefore, by storing the ratio value A in a table or the like in advance, Vo (t) = A × Vo (0) can be obtained, and any device can be corrected to a substantially true value.

  Here, the load output voltage is, for example, a step-up chopper when driving a load using DC power, such as a compressor motor, a fan motor, a stepping motor that drives an electronic expansion valve, or an electromagnetic valve of an air conditioner outdoor unit. The output voltage output from the circuit, and the no-load output voltage is an output voltage output from the boost chopper circuit when not in a loaded state. However, when there are a large number of loads (for example, a compressor and a communication circuit) in the system, a large load (such as a compressor) >> a small load (for example, a communication circuit) among these loads, It is good also as a no-load state with having stopped.

  Hereinafter, a first embodiment of the present invention will be described in detail with reference to FIGS. In FIG. 1, parts that may be regarded as the same as or the same as the components in FIG.

  In FIG. 1, this power supply apparatus detects an input current Vi of the boost chopper circuit 3 and an input current detector 10 that detects an input current Ii of the boost chopper circuit 3 based on a detection signal from a current sensor (for example, CT) 5. Therefore, the voltage dividing resistor circuit 11 of the resistors R1 and R2 connected in series, the voltage dividing resistor circuit 12 of the resistors R3 and R4 connected in series to detect the output voltage (output DC voltage) Vo, and the noise removing LPF ( A low-pass filter) 13 and the voltage passing through the LPF 13 are detected by A / D conversion, and the voltage is boosted based on the detected value and the zero cross detection of the AC power source 1 by the power source zero cross detector (power source phase detector) 8. And a control unit 14 such as a microcomputer for outputting a signal for turning on / off the switching element 3c of the chopper circuit 3 to the driving unit 7.

  As a modification, the same effect as an active filter can be obtained by inserting the boost choke coil (reactor) 3a and the switching element 3c shown in FIG. For example, the position may be changed as appropriate. The control unit 14 has the same function as that of the control unit 6 in FIG. 10, and the other parts are the same as those in FIG.

  Referring also to FIG. 2, the control unit 14 receives a voltage command unit 14 a that outputs a command value (ratio value) A for suppressing variations in output voltage, and an output voltage Vo (t) that has passed through the LPF 13 as A A / D conversion unit 14b that detects by performing A / D conversion, determination means 14c for switching the A / D converted output voltage Vo (t) between no load and load, and no load A no-load voltage storage means 14d for storing the output voltage Vo (0), a multiplication means 14e for multiplying the output voltage Vo (0) at the time of no load by the ratio value A, a voltage command value of this multiplication result and a load 14f for calculating the output voltage detection value Vo (t) at the time, a voltage controller 14g for calculating the correction amount of the input voltage detection value Vi (t) based on the calculation result, and a power supply zero-cross detection unit Based on the detection signal from 5, On the switching element 3c as include a switching operation controller 14h for generating an off timing.

  The control unit 14 multiplies the input voltage detection value Vi (t) by the operation value obtained by the voltage controller 14g, and the switching signal of the switching element 3c based on the switching timing by the switching operation controller 14h. And a current controller 14j for controlling the input current Ii in consideration of the multiplication result of the multiplication means 14i. The switching operation controller 14h and the current controller 14j may have a block configuration shown in FIG.

  The operation of the power supply apparatus having the above configuration will be described with reference to the processing system block diagram of FIG. 2 and the flowcharts of FIGS. The control unit 14 switches the switching element 3c based on the output voltage command value (applied voltage command value of the load 4) as in the prior art to set the output voltage to a predetermined value necessary for the load 4, and the input current waveform Into a sine wave shape. In order to improve the input AC waveform and reduce the higher harmonic current, the operation of the switching element 3c is prohibited for a predetermined period based on the zero cross point of the input power supply.

  The processing by the software executed in the present invention will be described. First, in the voltage command value calculation processing system, the output voltage Vo (0) at the time of no load is stored in the no load voltage storage means 14d by switching the determination means 14c. A voltage command value Vo * (t) is obtained using the no-load output voltage Vo (0). The determination unit 14c determines whether there is a no-load state or a loaded state depending on whether the load 4 is operating.

  The no-load output voltage Vo (0) is detected by creating a no-load state only for a predetermined period, and when detecting it, the no-load state is determined by a no-load determining means described later, and the detected value is stored and updated. Good. In addition, the detection of the no-load output voltage is performed by setting a predetermined time from the power-on of the power supply device to the start of load activation as a no-load state at the predetermined time, or by using an interval timer at a predetermined time. It is preferable to perform the operation when the operation is stopped.

Then, as shown in FIG. 3, the ratio value A is referred to from a table obtained empirically in advance, or is calculated based on the current output voltage Vo (output voltage Vo (t) under load) ( Step ST1). This ratio value A is multiplied by the output voltage Vo (0) obtained when there is no load to obtain a voltage command value Vo * (t) expressed by the following equation (1) (step ST2).
Vo * (t) = A × Vo (0) (1)

  The ratio value A is a value obtained in consideration of clearing of power supply harmonic regulations, and when the load 4 is a motor, a value obtained from a voltage value required by the motor control system according to the amount of the load. It does not matter whether it is obtained by table reference or calculation by function.

  As a reference, the relationship between the ratio value A and the load size (input current value) for clearing the power harmonic regulation is shown in Table 1 below. Table 1 is an example of the results obtained on a trial basis, and whether or not the power supply harmonic regulation is cleared depends on the ratio value A and the load. “◯” in the table means that the regulation is cleared, “Δ” means that the power supply condition may be NG, and “×” is NG.

  In the example of Table 1, when the ratio value A is set to 0.94, the power harmonic regulation can be cleared regardless of the magnitude of the load (input current value). The power supply conditions of “Δ” include power supply voltage standard values (100 V / 200 V in Japan, 220 V / 230 V / 240 V overseas), power supply frequency standard values (50 Hz / 60 Hz), power supply impedance values (domestic: power supply voltage). And IEC: No regulation).

  In the A / D conversion processing system that performs A / D conversion when detecting the output voltage, the input voltage, and the like, as shown in FIG. 4, the type of A / D conversion data (output voltage or input voltage) is determined (step). ST10). If the data type is output voltage, the A / D conversion result is filtered and substituted for Vo (t) (step ST11). Subsequently, the load state is determined (step ST12). If there is a load, the output voltage Vo (t) is left as it is. If there is no load, the output voltage Vo (t) is substituted for the initial value Vo (0) ( Step ST13).

  If the data type is an input voltage, the A / D conversion result is filtered and substituted into Vi (t) (step ST14). Subsequently, the load state is determined (step ST15). If there is a load, the input voltage Vi (t) is left as it is. If there is no load, the output voltage Vi (t) is substituted for the initial value Vi (0) ( Step ST16). For other data, processing corresponding to the data is executed (step ST17).

  In the output voltage control system that performs the voltage feedback control, as shown in FIG. 5, in the case of PI control, the voltage deviation Ve between the voltage command value Vo * (t) and the output voltage detection value Vo (t) under load is calculated. Calculation is performed by the computing means 14f (step ST20). A proportional term P (= Kp × Ve) is obtained for the voltage deviation Ve, and an integral term I (= Ki × sigma Ve) is obtained, thereby obtaining a command amplitude D (= P + I) (steps ST21 to ST24). ) To obtain a current command value. Kp is an arbitrary proportional gain, and Ki is an arbitrary integral gain.

  The interval time of the processing system described above is basically based on the relationship of the interval time of the voltage command value calculation processing system ≧ the interval time of the output voltage control processing system ≧ the interval time of the A / D conversion processing system. By the above processing, the voltage controller 14g, when the voltage command value is Vo * (t), multiplies the multiplication means 14i by multiplying the multiplication value for correcting the input voltage Vi so that the output voltage Vo (t) becomes Vo * (t). Output to.

  According to this, the input voltage, the output voltage, etc. in each processing system are obtained using the resistors R1, R2; R3, R4 of the same voltage dividing resistor circuits 11, 12, and the A / D converter reference voltage AVR. In addition, the voltage deviation Ve between the voltage command value Vo * (t) (= A × Vo (0)) and the output voltage Vo (t) varies between the resistors R3 and R4 of the voltage dividing resistor circuit 12 and the A / D converter reference. This corresponds to the amount corresponding to the variation of the voltage AVR.

  Therefore, in the switching section of the switching element 3c determined by the switching operation control 14h, the current controller 14j performs current control, and the output voltage Vo ( The voltage control that makes t) constant is taken into consideration.

  As the current control taking the multiplication result into account, if the switching operation control 14h and the current control 14j are configured as shown in FIG. 11, the output voltage command value in the current control may be changed.

  Thus, there are variations in the voltage dividing resistors R3 and R4, variations in the A / D converter reference voltage AVR, etc., and even if an error occurs in voltage detection in the current control, there is no influence due to the detection error due to voltage control. The output voltage Vo (t) is kept constant, the current control is stabilized, the variation of the input current waveform by the device is suppressed, and the applicability of the power supply device is improved.

Since the input current waveform also affects the input voltage Vi, the A / D conversion processing system may be executed by the routine shown in FIG. That is, an output voltage multiplied by the ratio value A is obtained by multiplying the output voltage Vo (0) at no load by the ratio Vi (t) / Vi (0) of the input voltage Vi at the time of load and no load ( Steps ST30 and ST31). According to this, the voltage command value Vo * (t) is expressed by the following equation (2).
Vo * (t) = A × Vo (0) × (Vi (t) / Vi (0)) (2)

  As a result, since fluctuations in the input voltage Vi are taken into account, even if the power supply voltage fluctuates, the input current waveform can be kept similar to the input voltage waveform, and current control can be further stabilized. In addition, since the voltage command value Vo * (t) is set by the output voltage Vo (0) when there is no load, the power supply voltage is decreased due to an increase in input current or the power supply voltage is increased or decreased due to the influence of other system connected devices. Nevertheless, the ratio between the input voltage peak value and the output voltage can be kept constant.

  Next, a second embodiment of the present invention will be described with reference to FIGS. This second embodiment corresponds to claim 7. In the first embodiment, the voltage is controlled so that the ratio between the no-load output voltage Vo (0) and the loaded output voltage Vo (t) becomes a predetermined value. In the second embodiment, no load is applied. The voltage is controlled so that the difference between the output voltage Vo (0) and the load output voltage Vo (t) becomes a predetermined value.

  That is, in the second embodiment, as shown in FIG. 7, when the AC input voltage (effective value) decreases from Vi (0) to Vi (1), the DC load voltage is changed from Vo (0) to Vo (1 On the other hand, when the AC input voltage increases from Vi (0) to Vi (2), the DC load voltage is increased from Vo (0) to Vo (2).

  Therefore, in terms of hardware, as shown in FIG. 8, a subtracting means 14e 'is used instead of the multiplying means 14e in FIG. 1 of the first embodiment. Other hardware configurations may be the same as in FIG. If the polarity of the subtraction value is negative, the subtraction means 14e ′ may be used as the addition means.

Referring also to FIG. 9, in calculating the voltage command value Vo * (t), a predetermined difference command value ΔV set in advance is read from the voltage command unit 14a and is subtracted by the subtracting means 14e ′. Subtraction with the no-load output voltage Vo (0) output from the no-load voltage storage means 14d is performed (steps ST41 and ST42). As a result, the subtraction means 14e ′ uses the following equation (3),
Vo * (t) = Vo (0) −ΔV (3)
The load voltage command value Vo * (t) is obtained, and this load voltage command value Vo * (t) is calculated as the load output voltage Vo (t) by the calculation means 14f as in the first embodiment.

  This difference command value ΔV is also determined empirically as with the ratio value A in the first embodiment, and the difference command value ΔV and load magnitude (input current value) for clearing the power harmonic regulation An example of the relationship is shown in Table 2 below. “◯”, “Δ”, and “×” in the table have the same meaning as in Table 1 above. According to Table 2, by setting the differential command value ΔV to 20 V, it is possible to clear the power harmonic regulation regardless of the magnitude of the load (input current value).

The load output voltage Vo (t) is controlled so as to follow the load voltage command value Vo * (t). Here, variations in the voltage dividing resistors R3 and R4 and variations in the A / D converter reference voltage AVR are reduced. If the detection error is E (usually about 5%), the load output voltage Vo (t) is
Vo (t) = Vo (0) −ΔV × (1 ± E)
= Vo (0) -ΔV ± ΔV × E
= Vo * (t) ± ΔV × E
The output error with respect to the load voltage command value Vo * (t) is ΔV × E.

On the other hand, the load output voltage Vo (t) when the load voltage command value Vo * (t) is directly output without using the difference command value ΔV is:
Vo (t) = Vo * (t) × (1 ± E)
= Vo * (t) ± Vo * (t) × E
Therefore, the output error is Vo * (t) × E.

  Thus, the output error when the difference command value ΔV is used is ΔV × E, while the output error when the difference command value ΔV is not used is Vo * (t) × E, Vo * (t). Since there is a relationship of> ΔV, according to the second embodiment, the output error due to the detection error E based on the variation of devices and the like can be significantly reduced.

  Moreover, even if the load voltage command value Vo * (t) is calculated, as shown in the above equation (3), only one subtraction (or addition) is required, so the equation (1) in the first embodiment is used. ), The calculation load on the control means can be reduced.

Further, in order to make the load voltage command value Vo * (t) correspond to the fluctuation of the AC input voltage, as in the first embodiment, the input voltage Vi (t) when there is a load and the input voltage Vi (0) when there is no load. ) And monitoring the ratio is preferable. That is, the load voltage command value Vo * (t) is
Vo * (t) = Vo (0) × (Vi (t) / Vi (0)) − ΔV (4)
It is preferable to obtain by the following formula. Further, even if the load voltage command value Vo * (t) is calculated by this equation (4), the number of operations is one less than the above equation (2) in the first embodiment, and accordingly, The calculation load on the control means can be reduced.

  In each of the above embodiments, voltage control is performed using the no-load output voltage and the load output voltage, but the rectified average value or effective value of the DC voltage rectified by the rectifier circuit 2 is detected. And a storage means for storing the rectified average value or effective value at no load, and instead of the no-load output voltage and the load output voltage, the rectified average value or effective value and detected rectified average of the storage means A value or an effective value may be used.

  In each of the above embodiments, the load voltage command value Vo * (t) is obtained based on the no-load output voltage Vo (0), but the present invention is not limited to this. In other words, in the case of a load (eg, a stepping motor used to drive an electronic expansion valve of an air conditioner) that is known to drop several volts from the no-load voltage when there is a load, the voltage drop is expected. It is also possible to adjust the load voltage command value.

That is, in the first embodiment, as shown in the above equation (1), the output voltage Vo (t) under load is controlled so that Vo (t) = A × Vo (0). The following equation (5), where k is the constant of the drop (voltage drop) rate of the load voltage when driving the load, and Vo ′ is the load voltage at an arbitrary time when driving the load:
Vo (t) = A × k × Vo ′ (5)
It is also possible to control the output voltage Vo (t) when there is a load.

In the second embodiment, as shown in the above equation (3), the output voltage Vo (t) under load is controlled so that Vo (t) = Vo (0) −ΔV. However, when the load voltage drop at the time of load driving is a constant Δk, and the load voltage at an arbitrary time at the time of load driving is Vo ′, the following equation (6):
Vo (t) = Vo ′ + Δk−ΔV (6)
It is also possible to control the output voltage Vo (t) when there is a load.

  According to the present invention, since the load output voltage in the power supply device is kept constant, the current control is stable, the power harmonic current can be reduced and the regulation can be cleared. It is applicable not only to household appliances in general but also to industrial equipment.

The schematic block diagram of the power supply device which shows 1st Embodiment of this invention. The processing system block diagram of the control means contained in the said 1st Embodiment. The schematic flowchart for operation | movement description of the said 1st Embodiment. The schematic flowchart for operation | movement description of the said 1st Embodiment. The schematic flowchart for operation | movement description of the said 1st Embodiment. The flowchart for demonstrating the modification of the said 1st Embodiment. The graph which shows the relationship between the alternating current input voltage and DC load voltage in 2nd Embodiment of this invention. The schematic block diagram of the power supply device which concerns on the said 2nd Embodiment. The schematic flowchart for operation | movement description of the said 2nd Embodiment. The schematic circuit diagram which shows the conventional power supply device. FIG. 11 is a schematic block diagram showing control means of the power supply device shown in FIG. 10. FIG. 11 is a schematic waveform diagram for explaining the operation of the power supply device shown in FIG. 10. FIG. 11 is a schematic waveform diagram for explaining operations of the power supply device shown in FIG. 10.

Explanation of symbols

1 Input power supply (AC power supply)
2 rectifier circuit 3 boost chopper circuit 3a boost choke coil 3b reverse blocking diode 3c switching element 3d smoothing capacitor 4 load 5 current sensor 6, 14 control unit 8 power supply zero cross detection unit 10 input current detection unit 11, 12 voltage dividing resistor circuit 13 LPF
A Voltage command ratio value ΔV Difference command value Ii Input current Vi, Vi (0), Vi (t) Input voltage Vo, Vo (0), Vo (t) Output voltage Vo * (t) Load voltage command value

Claims (11)

In the power supply device that improves the power factor by short-circuiting the AC power supply via a reactor when the AC power supply is converted into a DC voltage by a rectifying means to be a load voltage,
While switching the switching element of the power factor improvement means including the reactor, the switching element is turned on and off according to the comparison result between the input current and the input current reference signal of the input AC power supply voltage waveform. While the output voltage is used as the load voltage, the load detection means detects the no-load output voltage and the loaded output voltage during the current control so that the ratio between the no-load output voltage and the loaded output voltage becomes a predetermined value. The power supply device is characterized in that the voltage is controlled.   The power supply apparatus according to claim 1, wherein the predetermined ratio of the load output voltage to the no-load output voltage is a value obtained in advance according to a load state.   The power supply apparatus according to claim 1 or 2, wherein a ratio of an input voltage when there is a load and when there is no load is used as the predetermined value.   The power supply apparatus according to claim 3, wherein a rectified average value or an effective value is used instead of the input voltage. In the power supply device that improves the power factor by short-circuiting the AC power supply via a reactor when the AC power supply is converted into a DC voltage by a rectifying means to be a load voltage,
While switching the switching element of the power factor improvement means including the reactor, the switching element is turned on and off according to the comparison result between the input current and the input current reference signal of the input AC power supply voltage waveform. While the output voltage is used as a load voltage, the load detection means detects the no-load output voltage and the loaded output voltage during current control so that the difference between the no-load output voltage and the loaded output voltage becomes a predetermined value. The power supply device is characterized in that the voltage is controlled.   When voltage control is performed so that the difference between the no-load output voltage and the load output voltage becomes a predetermined value, a value obtained by subtracting the predetermined value from the no-load output voltage is used as a load voltage command value. The power supply device according to claim 5.   A means for detecting the input AC power supply voltage is provided, and when the AC detection voltage becomes larger than the start of control, the load voltage command value is increased, and when the AC detection voltage becomes lower than the start of control, The power supply apparatus according to claim 1, wherein the load voltage command value is reduced.   When calculating the load voltage command value by subtracting a predetermined value from the no-load output voltage, multiply the no-load output voltage by the ratio of the no-load AC power supply voltage and the loaded AC power supply voltage The power supply device according to claim 5, wherein the power supply device is a power supply device.   6. A value obtained by adding a predicted value of a voltage drop caused by load driving from the load output voltage is used in place of the no-load output voltage used for calculating the load voltage command value. 8. The power supply device according to any one of items 7.   The power supply apparatus according to any one of claims 1 to 9, wherein a rectified average value or an effective value is used in place of the no-load output voltage and the load output voltage.   The power supply apparatus according to any one of claims 1 to 10, wherein a no-load state is determined by a no-load determination means, and a detection value at the time of no-load is stored and updated.

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