JP6226785B2 - Power supply device, power supply device control method, and control program - Google Patents

Description

  The present invention relates to a power supply device, a control method for the power supply device, and a control program in a power system of various appliances such as home appliances and industrial equipment.

In recent years, in order to solve the problem of harmonic current flowing into the power systems of various appliances such as home appliances and industrial equipment, the power source in the equipment uses the energy storage effect due to the operation of the inductor and switching element to increase the power factor. An AC / DC converter circuit (AC-DC converter) that boosts the output voltage while improving is used.
In the control in this AC-DC converter, the AC voltage value (input voltage measurement value Vin) is set to the voltage difference value (Ev) between the DC voltage value (output voltage measurement value Vdc) and its target value (target output voltage value Vref). According to the value obtained by multiplication, the conduction ratio of the switching element (the ratio of the time during which the switching element is turned on in the switching period of the switching element is determined. The time ratio is DUTY) is improved. (PFC: Power Factor Correction).

  For example, as disclosed in Patent Document 1, such a power supply device detects an AC / DC conversion unit (PFC unit) including at least a switching element, an inductor, and a diode, which obtains a DC voltage from an AC power source, and a current value of the AC power source. An input current detector, an input voltage detector that detects the voltage value of the AC power supply, an output voltage detector that detects a DC voltage value output from the AC / DC converter circuit, a current detector, an input voltage detector, and an output A power unit is improved based on each value obtained by the voltage detection unit, and a control unit that performs PFC control of the operation of the switching element so that the DC voltage value becomes a preset target value (Patent Document 1). FIG. 1).

  PFC control is generally performed as follows. In the voltage control loop, the control unit calculates a voltage difference value Ev between the output voltage measurement value Vdc and the target output voltage value Vref, and generates a voltage error signal VPI. Thereafter, the input current set value Iref is obtained by multiplying the voltage error signal VPI by a value obtained by normalizing the input voltage measurement value Vin. Next, the control unit calculates a current difference value Ei between the input current setting value Iref and the input current measurement value Iin in the current control loop, and generates a current error signal IPI.

  Then, by sequentially converting the conduction ratio (DUTY) of the switching element according to the signal level of the current error signal IPI, the waveform of the input voltage measurement value Vin and the input current measurement value Iin are similar, and the power factor becomes 1. In other words, control is performed so that the phase of the input voltage and the input current is in phase, and the DC voltage becomes a predetermined target output voltage value Vref.

  Here, a ripple component having a frequency twice the AC power supply frequency is superimposed on the DC voltage (output voltage measurement value Vdc) obtained by the output voltage detection unit due to the characteristics of the AC / DC converter circuit. If the above control calculation is performed while the ripple component is included in the DC voltage, the influence of the ripple component appears in the voltage error signal VPI, and eventually the waveform of the input current (input current measured value Iin) is distorted. .

  In order to eliminate this ripple component, a value obtained through a low-pass filter with a slow response speed (cutoff frequency of about 1 Hz) is used as the DC voltage value when calculating the voltage difference value Ev in the voltage control loop. It is common. On the other hand, since the current error signal IPI of the current control loop sequentially controls the duty so that the input current (input current measurement value Iin) follows a sinusoidal shape, it is common to set the cutoff frequency higher. .

JP 2008-289228 A JP 2012-1000048 A JP 2012-1000048 A

  However, according to the above-described configuration, when the power supply device is connected to, for example, a 200V commercial AC power supply and an input AC voltage is supplied, the DC voltage is the target output voltage value Vref (for example, 400V) when the PFC is activated. However, since the response of the voltage control loop is slow, the voltage difference (voltage difference value Ev) from the target output voltage value Vref is large, such as when the target output voltage value Vref is set to a constant value in advance. Due to the characteristic that the circuit performs a boost operation, the current error signal IPI of the current control loop rapidly increases. As a result, during the period until it rises to the target output voltage value Vref, it operates in a state where the conduction ratio (DUTY) of the switching element is widened (a state in which the switching element is on for a long period), and the inrush current at the start of PFC is The DC voltage increases and exceeds the target output voltage value Vref. On the other hand, since the voltage control loop reduces the response speed as described above, there is a problem that it takes time until the DC voltage returns to the target output voltage value Vref, and the responsiveness of the power supply device is poor.

  As a technique for solving such a problem, there is a power supply device disclosed in, for example, Japanese Unexamined Patent Application Publication No. 2012-1000048 (see Patent Document 2) and Japanese Unexamined Patent Application Publication No. 2012-1000048 (see Patent Document 3). However, according to this type of power supply device, the measurement circuit of the input current measurement value Iin input by AC is a separate circuit for the positive side and the negative side of the input current. Specifically, referring to FIG. 1, the measurement of the positive input current among the input currents flowing from the commercial AC power supply (AC power supply) through the first and second AC input terminals 1 a and 1 b respectively. The circuit is composed of a circuit including a shunt resistor R1, and the negative side input current measuring circuit is composed of a circuit including a shunt resistor R2. For this reason, as illustrated in FIG. 6, an unbalance occurs in the waveforms of the positive side and the negative side in one cycle of the input current due to a difference in error such as component variations of each measurement circuit. This may increase the harmonic current.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide harmonic current when the input current measurement circuit is a separate circuit for the positive side and the negative side of the input current. Is to provide a power supply apparatus, a control method for the power supply apparatus, and a control program.

  One aspect of the present invention is an AC / DC conversion unit including at least a switching element, an inductor, and a diode that obtains a DC voltage from an AC voltage of an AC power source, an input voltage detection unit that detects a voltage value of the AC power source, and the AC power source. An input current detection unit that detects a current value of the output current, an output voltage detection unit that detects a voltage value of a DC voltage output from the AC / DC conversion unit, the input current detection unit, the input voltage detection unit, and the output voltage detection The switching element so that the voltage value of the DC voltage becomes a preset target output voltage value based on the current value of the AC power supply obtained by each unit, the voltage value of the AC power supply, and the voltage value of the DC voltage. A control unit that controls on / off of the voltage, and the control unit is a voltage difference value between the voltage value of the DC voltage and the target output voltage value every half cycle of the AC voltage of the AC power supply. Generates Luo voltage error signal, based on the value of the voltage error signal, a power supply device and correcting the current values detected every half cycle by the input current detecting unit.

  One embodiment of the present invention is the power supply device described above, in which the control unit generates a voltage error signal generated in the first half cycle of the AC voltage of the AC power supply and a voltage error signal generated in the second half cycle. When the absolute value of the difference value exceeds the specified value, the current value detected by the input current detection unit is multiplied by a coefficient in either the first half cycle or the second half cycle.

Another embodiment of the present invention, there is provided a power supply apparatus described above, the control unit, the DC voltage voltage value and the target output voltage value to the voltage difference value voltage gain voltage obtained by multiplying of A voltage error signal generation unit that generates an error signal, and a difference determination that corrects the current value detected every half cycle by the input current detection unit based on the value of the voltage error signal generated by the voltage error signal generation unit A multiplier that generates an input current setting value based on the voltage value of the AC power supply and the voltage error signal, and a PID based on a current difference value between the input current setting value and the current value of the AC power supply. a current error signal generator for generating a current error signal by performing arithmetic processing, a duty operation unit for calculating the duty of the signal for turning on / off control of the switching element based on the current error signal, said voltage Based on the difference between the difference signal and the ON / OFF control of the threshold, it has a, an offset computing section for generating an offset value in the duty operation unit, wherein the voltage gain is determined by the PID operation processing.

Another embodiment of the present invention, there is provided a power supply apparatus described above, the control unit, in the duty operation unit, the current error signal IPI which has been determined by the PID operation processing, the duty ratio DUTY, DUTY = Dmax- IPI × Kcnv (Dmax is the maximum output value (upper limit value) of the duty ratio DUTY, and Kcnv is a coefficient for converting the current error signal IPI into the duty ratio DUTY).

One embodiment of the present invention is the power supply device described above, in which the PID calculation process in the current error signal generation unit is performed by setting a current difference value Ei (t) to Ei (t) = input current setting value Iref−. The current error signal IPI = Ui (t) calculated by the input current measurement value Iin (t) and obtained by the PID calculation process is expressed as Ui (t) = Kip × Ei (t) + {Kii × Ei (t−1). + Ui (t−1)} + Kid × {Ei (t) −Ei (t−n)} (Ui (t−1) is the current error signal IPI obtained in the previous PID calculation process, and Ei (t −1) and Ei (t−n) indicate current difference values Ei in the PID calculation processing one time before and n times before, respectively, and Ei (t) is a value based on the current processing result. Kii and Kid are ratios in the PID calculation process, respectively. (P) coefficients, integral (I) coefficient shows a differential (D) factor.

  Further, according to one aspect of the present invention, the input voltage detection unit detects an AC voltage detection process in which the voltage value of the AC power supply is detected, and the input current detection unit detects an AC current detection process in which the current value of the AC power supply is detected. A DC voltage detection process in which an output voltage detector detects a voltage value of a DC voltage output from an AC / DC converter consisting of at least a switching element, an inductor and a diode to obtain a DC voltage from the AC voltage of the AC power supply; and the control unit Is based on the current value of the AC power source, the voltage value of the AC power source, and the voltage value of the DC voltage obtained by the input current detection unit, the input voltage detection unit, and the output voltage detection unit, respectively. A control process for controlling on / off of the switching element so that the voltage value becomes a preset target output voltage value, and the control process includes a half of the AC voltage of the AC power supply. A voltage error signal is generated from a voltage difference value between the voltage value of the DC voltage and the target output voltage value every period, and detected by the input current detection unit every half cycle based on the value of the voltage error signal A method of controlling a power supply device, comprising: a step of correcting a current value.

  In one embodiment of the present invention, the computer includes an AC voltage detection unit in which the input voltage detection unit detects the voltage value of the AC power supply, and an AC current detection unit in which the input current detection unit detects the current value of the AC power supply. The output voltage detection unit obtains a DC voltage from the AC voltage of the AC power source, and at least a DC voltage detection means for detecting a voltage value of the DC voltage output by the AC / DC conversion unit composed of a switching element, an inductor and a diode; The voltage of the DC voltage based on the current value of the AC power source, the voltage value of the AC power source, and the voltage value of the DC voltage obtained by the input current detection unit, the input voltage detection unit, and the output voltage detection unit, respectively. The switching element functions as a control unit that controls on / off of the switching element so that the value becomes a preset target output voltage value, and the control unit A voltage error signal is generated from a voltage difference value between the voltage value of the DC voltage and the target output voltage value every half cycle of the current voltage, and the input current detection unit performs a half cycle based on the value of the voltage error signal. It is a control program for the power supply device for causing it to function as a means for correcting the current value detected every time.

  As described above, according to the present invention, it is possible to prevent imbalance between the input currents on the positive side and the negative side and suppress an increase in the harmonic current.

It is a circuit block diagram which shows the power supply device in this embodiment. It is a circuit block diagram of the control part 15 in this embodiment. It is a figure which shows the flowchart of the correction target determination process by the control part 15 in this embodiment. It is a figure which shows the flowchart of the input current correction process by the control part 15 in this embodiment. It is a figure which shows an example of the waveform of the input voltage and input current after correction | amendment of a correction coefficient. It is a figure which shows an example of the waveform of the input voltage and input current before correction | amendment of a correction coefficient.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a circuit configuration diagram illustrating a power supply device according to the present embodiment.
The power supply device shown in FIG. 1 converts the AC voltage of the first and second AC input terminals 1a and 1b connected to a commercial AC power supply (AC power supply) into a DC voltage, and first and second DC output terminals. This is a power supply device that generates an output voltage that is a DC voltage between 2a and 2b and supplies the DC voltage to a DC-DC converter or the like connected between these output terminals.

  The power supply apparatus includes an input stage filter circuit FLTR, a relay circuit RY, and a power factor improvement between the first and second AC input terminals 1a and 1b and the first and second DC output terminals 2a and 2b. The circuit 10 is provided in order. In the present invention, the power factor correction circuit 10 functions as an AC / DC converter that obtains a DC voltage from an AC voltage of an AC power supply, and includes at least a switching element, an inductor, and a diode as will be described later. The power supply apparatus further includes an input voltage detection unit 11 and an input current detection unit 12 for on / off control of switching elements (transistors Q1 and Q2, diodes BD1 and BD2) included in the power factor correction circuit 10. A switch drive unit 13, an output voltage detection unit 14, and a control unit 15.

  In the power factor correction circuit 10 of FIG. 1, a diode D1, a transistor Q1, and a resistor R1 are connected in series between the DC output terminal 2a and the DC output terminal 2b. A diode D2, a transistor Q2, and a resistor R2 are connected in series between the DC output terminals 2a and 2b. A diode BD1 and a diode BD2 are connected in parallel to the transistor Q1 and the transistor Q2, respectively, and these two parallel circuits function as switching elements of the power factor correction circuit 10.

  The connection point between the diode D1 and the transistor Q1 is connected to the AC input terminal 1a side via the inductor L1, and the connection point between the diode D2 and the transistor Q2 is connected to the AC input terminal 1b side via the inductor L2. Connected to. An electrolytic capacitor C2 is also connected between the DC output terminals 2a and 2b. The transistors Q1 and Q2 are N-channel MOS transistors in FIG. 1, but in this case, the diodes BD1 and BD2 may be parasitic diodes in the MOS transistors. Further, as the transistors Q1 and Q2, an NPN bipolar transistor or an IGBT (Insulated Gate Bipolar Transistor) may be used.

  When the transistor Q1 is on during the positive voltage period of the AC power supply connected to the AC input terminals 1a and 1b, the first closed circuit including the AC input terminal 1a, the inductor L1, the transistor Q1, the diode BD2, and the inductor L2 is used. A circuit is formed and energy is stored in inductor L1 and inductor L2. Next, when the transistor Q1 is turned off, the second closed circuit composed of the AC input terminal 1a, the inductor L1, the diode D1, the electrolytic capacitor C2, the diode BD2, and the inductor L2 transfers the energy stored in the inductor L1 and the inductor L2. The electrolytic capacitor C2 is supplied, and the electrolytic capacitor C2 is charged to a value higher than the AC power supply voltage.

On the other hand, in the negative voltage period of the AC power supply, when the transistor Q2 is on, a third closed circuit including the AC input terminal 1b, the inductor L2, the transistor Q2, the diode BD1, and the inductor L1 is formed, and the inductor L2 To store energy. Next, when the transistor Q2 is turned off, the fourth closed circuit including the AC input terminal 1b, the inductor L2, the inductor L1, the diode D2, the electrolytic capacitor C2, and the diode BD1 transfers the energy stored in the inductor L2 and the inductor L1. The electrolytic capacitor C2 is supplied, and the electrolytic capacitor C2 is charged to a value higher than the AC power supply voltage.
In the positive voltage period or negative voltage period of the AC power supply, only one of the transistors Q1 and Q2 is required to be turned on / off as described above, but the two transistors are connected using the same gate signal. It may be turned on / off.

  With such a configuration, the power factor correction circuit 10 turns on / off the switching element and controls the voltage between both terminals of the electrolytic capacitor C2 to be constant, but the AC power supply connected to the AC input terminals 1a, 1b It is necessary to perform on / off control of the switching element at a frequency higher than the voltage frequency. Therefore, the control unit 15 performs a calculation process for determining the conduction ratio (duty ratio DUTY) of the switching element based on an AC input voltage, an AC input current, and an output voltage that is a DC voltage.

  Therefore, in the power factor correction circuit 10, both ends of each of the resistors R 1 and R 2 are connected to the input current detection unit 12, and the gate terminal and source terminal of each of the transistors Q 1 and Q 2 are connected to the switch driving unit 13. The DC output terminals 2a and 2b are connected to the output voltage detection unit 14. In addition, the AC input terminals 1 a and 1 b side of the inductors L 1 and L 2 are connected to the input voltage detection unit 11.

  The input voltage detection unit 11 detects an AC voltage and outputs an input voltage measurement value Vin (AC power supply voltage value) to the control unit 15. The input current detection unit 12 detects the alternating current value flowing through the resistors R1 and R2, and outputs the input current measurement value Iin to the control unit 15. The output voltage detector 14 (DC voltage detector) detects the voltage between the DC output terminals 2 a and 2 b and outputs the output voltage measurement value Vdc to the controller 15.

  The control unit 15 generates a duty ratio DUTY based on the voltage levels of these input signals, and outputs the duty ratio DUTY to the switch driving unit 13. The switch drive unit 13 generates a drive signal for the switching element based on the duty ratio DUTY.

  Further, the control unit 15 turns on the switch of the relay circuit RY. For this reason, the input voltage measurement value Vin is monitored, and the AC power source is peak-charged with the electrolytic capacitor C2. The time when the AC power source effective value x√2 is reached and the effective value of the AC power source can be recognized is reached. After the elapse of time, the switch of the relay circuit RY is turned on to lower the impedance with respect to the AC input terminal of the power factor correction circuit 10. The resistor (resistor R3) in the relay circuit RY forms a CR time constant circuit together with the capacitor capacity provided before and after the relay circuit RY, and acts as an electrolytic capacitor C2 of the power factor correction circuit 10 before the start of the switching operation. This prevents a sudden current from flowing.

FIG. 2 is a circuit configuration diagram of the control unit 15 in the present embodiment.
The control unit 15 includes a voltage error signal generation unit 21, a duty calculation unit 23, normalization calculation units 31 to 33, comparators 41 and 43, a multiplier 42, a VPI difference determination unit 44, and an offset calculation unit 24. When the difference value between the voltage error signal VPI (+) and the voltage error signal VPI (−) exceeds a first specified value (described later), the control unit 15 normalizes every half cycle. The correction coefficient k3 of the arithmetic unit 33 is corrected, and the feedback control shown below is performed. On the other hand, when the difference value is equal to or less than the first specified value, the following feedback control is performed without correcting the correction coefficient k3 of the normalization calculation unit 33.

  The VPI difference determination unit 44 is a circuit that corrects the correction coefficient k3 of the normalization calculation unit 33 based on the voltage error signal VPI generated by the voltage error signal generation unit 21, and forms a characteristic part of the present embodiment. . Details will be described later.

  The voltage error signal generation unit 21 includes a comparator 41 and a VPI generation unit 26, and generates a voltage error signal VPI. The comparator 41 is a value obtained by normalizing the output voltage measurement value Vdc by the normalization calculation unit 31 (a value obtained by multiplying the output voltage measurement value Vdc by a coefficient k1, for example, 1/100 so as to match the operating voltage of the control unit 15. ) And a preset target output voltage value Vref and take the difference to generate a voltage difference value Ev.

  The VPI generator 26 multiplies the voltage difference value Ev and the voltage gain Gv to generate a voltage error signal VPI. Here, as is well known in the feedback control system, calculation processing of proportional P, integral I, and differential D, which is called PID, is added to the voltage error, and these are combined and fed back as necessary, and the response of the system It is done to improve sex. The voltage gain Gv is a value obtained by this PID calculation process.

  The multiplier 42 is a value obtained by normalizing the input voltage measurement value Vin by the normalization calculation unit 32 (for example, a value obtained by dividing the input voltage measurement value Vin by the maximum value k2 so as to match the operating voltage of the control unit 15). The input current set value Iref is generated by multiplying the voltage error signal VPI.

The current error signal generation unit 22 includes a comparator 43 and an IPI generation unit 27, and generates a current error signal IPI.
The comparator 43 normalizes the input current measurement value Iin by the normalization calculation unit 33 (a value obtained by multiplying the input current measurement value Iin by a coefficient k3 so as to match the operating voltage of the control unit 15) and the input current setting. The value Iref is compared and the difference is taken to generate a current difference value Ei. The IPI generator 27 multiplies the current difference value Ei and the current gain Gi to generate a current error signal IPI. The current gain Gi is a value obtained by the PID calculation process, similarly to the voltage gain Gv. Details of the PID calculation process in the current control loop will be described later.

  Based on the current error signal IPI, the duty calculation unit 23 calculates a pulse width (duty ratio DUTY) for turning on the switching element using, for example, an arithmetic expression for converting the current error signal IPI to the duty ratio DUTY, Output to the switch drive unit 13. The switch driving unit 13 determines whether or not to perform the switching operation at the input duty ratio DUTY based on a control operation command or the like, outputs a drive signal, and turns on / off the switching element. By executing this switching operation, the waveform of the input voltage measurement value Vin and the input current measurement value Iin is similar, and the power factor becomes 1, that is, the input voltage measurement value Vin and the input current measurement value Iin. Control is performed so that the phase is in phase and the output voltage, which is a DC voltage, becomes a predetermined target output voltage value Vref.

  The offset calculation unit 24 generates an offset value Offset based on the difference between the offset determination threshold value THoffset and the voltage error signal VPI. The offset determination threshold value THoffset is a preset value, and can be set to improve the responsiveness of the voltage control loop of the power supply device, for example, as in Patent Documents 2 and 3 described above. The offset calculation unit 24 outputs the generated offset value Offset to the duty calculation unit 23.

  In the above circuit configuration, when the voltage difference (voltage difference value Ev) increases, the current or voltage level of the error signal (IPI) increases and the duty is increased (the switching element is turned on for a long period). When the switching operation is performed and the voltage difference (voltage difference value Ev) decreases, the current or voltage level of the error signal (IPI) decreases, and the logic that performs the switching operation in a state where the duty is narrowed (a state in which the switching element is turned on is short). It has a configuration.

Next, feedback control in the control unit 15 will be described. The feedback control is output voltage control for controlling the output voltage so as to become a preset target value. Details of the feedback control will be described below.
First, the control unit 15 acquires the input voltage measurement value Vin from the input voltage detection unit 11, and performs a calculation process of the input current set value Iref in the voltage control loop. The calculation is performed by the multiplier 42 according to the following equation (1), and the normalization calculation unit 32 normalizes the input voltage measurement value Vin to match the operating voltage of the control unit 15 (NVin). (Multiplied by the maximum value k2 of the input voltage measurement value Vin).
Iref = VPI × NVin (1)

Next, the control unit 15 acquires the input current measurement value Iin from the input current detection unit 12, and performs a calculation process of the current error signal IPI in the current control loop. The calculation is performed by the current error signal generation unit 22 based on the input current setting value Iref and the acquired input current measurement value Iin (t) by the PID calculation expressed by the following equations (2) to (4).
Current difference value Ei (t) = input current set value Iref−input current measurement value Iin (t) (2)
Ui (t) = Kip × Ei (t) + {Kii × Ei (t−1) + Ui (t−1)} + Kid × {Ei (t) −Ei (t−n)} (3)
IPI = Ui (t) (4)
Here, Ui (t) is the current error signal IPI obtained by the current PID calculation process, and Ui (t−1) is the current error signal IPI obtained by the previous PID calculation process. Ei (t−1) and Ei (t−n) indicate current difference values Ei in the PID calculation process one time before and n times before, respectively, and Ei (t) is a value based on the current processing result. is there. Kip, Kii, and Kid represent a proportional (P) coefficient, an integral (I) coefficient, and a derivative (D) coefficient, respectively, in the PID calculation process.

Next, the control unit 15 calculates the duty ratio DUTY in the duty calculation unit 23 according to the following equation (5) based on the current error signal IPI obtained by the PID calculation process.
DUTY = Dmax−IPI × Kcnv (5)
Here, Dmax is the maximum output value (upper limit value) of the duty ratio DUTY, and is a value preset in the control unit 15 together with the minimum output value Dmin (lower limit value). Kcnv is a coefficient used when the current error signal IPI is converted into the duty ratio DUTY, is a coefficient value calculated in advance by experiment or simulation, and is also a value set in the control unit 15.

Subsequently, the control unit 15 determines whether or not the value calculated by the previously calculated voltage error signal VPI exceeds a preset threshold value (pulse width control threshold value, hereinafter referred to as an offset determination threshold value THoffset). To do. When it is determined that the voltage error signal VPI exceeds the offset determination threshold THoffset, the time ratio DUTY, which is the previous processing result, becomes the time ratio DUTY in this update cycle as it is. On the other hand, when it is determined that the voltage error signal VPI is equal to or less than the offset determination threshold value THoffset, the control unit 15 uses the offset calculation unit 24 to calculate the offset value Offset based on the difference between the offset determination threshold value THoffset and the voltage error signal VPI as follows: Calculate according to (6).
Offset = (THoffset−VPI) × Koffset (6)
Here, Koffset is a coefficient value calculated in advance by experiment or simulation, and is a value set in the control unit 15.

Next, the control unit 15 calculates (subtracts) the duty ratio DUTY in accordance with the following equation (7) using the offset value Offset obtained in the equation (6) in the duty calculating unit 23.
DUTY (t) = DUTY (t−1) −Offset (7)
Here, DUTY (t) is the duty ratio DUTY obtained in the current subtraction process, and DUTY (t−1) is calculated in equation (5) of the previous duty ratio DUTY update control (PWM output control). The ratio is DUTY. In this subtraction process, DUTY (t) is calculated so as to be between the maximum output value Dmax (upper limit value) and the minimum output value Dmin (lower limit value).

  The control unit 15 outputs the duty ratio DUTY (t) calculated in Expression (7) to the duty ratio DUTY in this update cycle in the duty calculation unit 23 and outputs it to the switch driving unit 13.

  The switch drive unit 13 determines whether or not to perform the switching operation at the input duty ratio DUTY based on a control operation command or the like, outputs a drive signal, and has a pulse width gate corresponding to the duty ratio DUTY A signal is output to turn on / off the switching elements (transistors Q1, Q2). By executing this switching operation, the waveform of the input voltage measurement value Vin and the input current measurement value Iin is similar, and the power factor becomes 1, that is, the input voltage measurement value Vin and the input current measurement value Iin. Control is performed so that the phase is in phase and the DC voltage becomes a predetermined target output voltage value Vref.

As described above, the control unit 15 measures the input voltage Vin, the input current Iin, and the output voltage Vo (output voltage measurement value Vdc) for each update cycle in the feedback control. The control unit 15 calculates a voltage difference value Ev between the output voltage measurement value Vdc and the target output voltage value Vref, and generates a voltage error signal VPI. Thereafter, the control unit 15 multiplies the voltage error signal VPI by the value obtained by normalizing the input voltage measurement value Vin to obtain the input current set value Iref. Next, the control unit 15 calculates a current difference value Ei between the input current set value Iref and the input current measurement value Iin, and generates a current error signal IPI.
Then, the control unit 15 sequentially converts the conduction ratio (DUTY) of the switching element according to the signal level of the current error signal IPI, and controls the DC voltage to be a predetermined target output voltage value Vref.

  Next, the operation of the control unit 15 will be described. FIG. 3 is a diagram illustrating a flowchart of correction target determination processing by the control unit 15 in the present embodiment. FIG. 4 is a diagram illustrating a flowchart of input current correction processing by the control unit 15 in the present embodiment.

Schematically, the control unit 15 performs correction target determination processing. The correction target determination process determines whether or not to correct the correction coefficient k3 of the normalization calculation unit 33. Further, in the correction target determination process, when the control unit 15 determines to correct the correction coefficient k3, the correction coefficient of the first half cycle in the AC voltage of the AC power supply and the correction of the second half cycle in the AC voltage of the AC power supply are performed. This is a process for determining which correction coefficient of the coefficient is to be corrected.
The control unit 15 performs input current correction processing after performing correction target determination processing. The input current correction process is a process for correcting the correction coefficient of the correction target determined in the correction target determination process.

First, the operation of the correction target determination process of the control unit 15 will be described.
In step S101, the control unit 15 performs the feedback control described above for each update cycle. In the process of this feedback control, the control unit 15 acquires, in the VPI difference determination unit 44, the voltage error signal VPI generated by the voltage error signal generation unit 21 every half cycle of the AC voltage of the AC power supply as an operation amount. The VPI difference determination unit 44 includes a voltage error signal VPI acquired in the first half cycle of the AC voltage of the AC power supply (hereinafter referred to as “first half cycle”) and the second half cycle of the AC voltage of the AC power supply (hereinafter referred to as “the first half cycle”). The absolute value of the difference value from the voltage error signal VPI acquired in “the latter half cycle”) is calculated. The voltage error signal VPI acquired when the first half cycle, that is, when the AC voltage is positive, is referred to as a voltage error signal VPI (+). On the other hand, the voltage error signal VPI acquired when the latter half cycle, that is, when the AC voltage is negative, is defined as the voltage error signal VPI (−).

  In step S102, the VPI difference determination unit 44 determines whether or not the calculated absolute value exceeds the first specified value. When the calculated absolute value exceeds the first specified value (step S102: YES), the VPI difference determination unit 44 proceeds to step S103. On the other hand, when the calculated absolute value is equal to or smaller than the first specified value (step S102: NO), the VPI difference determination unit 44 proceeds to step S106. The first threshold value is a value determined in advance according to a difference in error such as component variations between the positive-side input current measurement circuit and the negative-side input current measurement circuit. In the present embodiment, the first specified value corresponds to the absolute value when the harmonic current resulting from the variation in the components of the measurement circuit becomes the limit value of the allowable range. Therefore, when the absolute value exceeds the first specified value in step S102, the harmonic current resulting from the above-described waveform imbalance between the positive side and the negative side in one cycle of the input current exceeds the allowable range. Means that. Conversely, the absolute value being equal to or less than the first specified value means that the harmonic current resulting from the waveform imbalance is within an allowable range. However, the present invention is not limited to this example, and the first specified value can be arbitrarily set as long as the harmonic current can be suppressed.

  In step S103, the VPI difference determination unit 44 determines which of the voltage error signal VPI (+) and the voltage error signal VPI (−) is greater. Specifically, for example, the VPI difference determination unit 44 subtracts the voltage error signal VPI (−) from the voltage error signal VPI (+). If the subtracted value is positive (step S103: YES), the VPI difference determination unit 44 determines that the voltage error signal VPI (+) is larger than the voltage error signal VPI (−), and proceeds to step S104. On the other hand, if the subtracted value is negative (step S103: NO), the VPI difference determination unit 44 determines that the voltage error signal VPI (+) is smaller than the voltage error signal VPI (−), and proceeds to step S105. .

In step S104, the control unit 15 sets, in the normalization calculation unit 33, k3 that multiplies the input current measurement value Iin in the first half cycle to an initial value, and k3 that multiplies the input current measurement value Iin in the second half cycle. For example, it is set to 1.0. Note that k3 that multiplies the input current measurement value Iin in the first half cycle is K _pos, and k3 that multiplies the input current measurement value Iin in the second half cycle is K _neg . The control unit 15 ends the correction target determination process after setting K _{pos and} K _neg to arbitrary values. The initial value is a correction coefficient value determined in advance through experiments or the like.

In step S105, the control unit 15 sets, in the normalization calculation unit 33, K _pos to multiply the input current measurement value Iin in the first half cycle to a certain constant, for example, 1.0, and the input current in the second half cycle. K _neg multiplied by the measured value Iin is set to an initial value. After setting K _{pos and} K _neg , the control unit 15 ends the correction target determination process.

In step S106, the control unit 15 causes the normalization calculation unit 33 to use K _pos that multiplies the input current measurement value Iin in the first half cycle and K _neg that multiplies the input current measurement value Iin in the second half cycle. For example, it is set to 1.0 and the correction target determination process is terminated.

Next, the operation of the input current correction process of the control unit 15 will be described.
In step S201, the control unit 15 has a timer as shown in FIG. 4, and determines whether or not a predetermined time has elapsed since execution of any one of steps S202 to 205 described later. . When the specified time has elapsed (step S201: YES), the control unit 15 proceeds to step S202. On the other hand, when the specified time has not elapsed (step S201: NO), the control unit 15 proceeds to step S206. Here, the specified time is a time during which the control unit 15 can determine the correction coefficient k3 corrected by the normalization calculation unit 33. When the specified time is exceeded, the correction coefficient k3 is corrected again. Note that at the first time of the input current correction process, since any process of Step S202 to Step 205 described later is not executed, the control unit 15 proceeds to Step S202.

In step S202, the control unit 15 sets the specified value determination number n to 0 (zero). Here, the specified value determination number n is a value used for determining the correction coefficient k3 corrected by the control unit 15 in the normalization calculation unit 33, and feedback control is performed using the corrected correction coefficient k3. Indicates the number of times Note that the initial value of the specified value determination number n is 0 (zero).
In step S <b> 203, the control unit 15 determines whether the correction target, that is, the correction coefficient to be corrected is K _neg or K _pos . Specifically, in the correction target determination process, when the correction target is the positive side, that is, when the process of step S104 is executed (step S203: YES), the control unit 15 performs the correction coefficient for correction K _pos . And the process proceeds to step S204. On the other hand, in the correction target determination process, the control unit 15 determines that the correction coefficient to be corrected is K _neg when the correction target is negative, that is, when the process of step S105 is executed (step S203: NO). The process proceeds to step S205.

In step S204, when the control unit 15 determines that the correction coefficient is K _pos , K _pos is increased by multiplying or adding a constant to K _pos . For example, the constant is set in advance through experiments or the like.
In step S205, the control unit 15, when the correction factor is determined to be _{K neg,} multiplied by a constant _{K neg} or by _adding, increasing _{K neg.}

  In step S206, the control unit 15 performs the above-described feedback control after increasing the correction coefficient in step S204 or step S205. In the process of this feedback control, the control unit 15 acquires, in the VPI difference determination unit 44, the voltage error signal VPI generated by the voltage error signal generation unit 21 every half cycle of the AC voltage of the AC power supply as an operation amount. The VPI difference determination unit 44 calculates an absolute value of a difference value between the voltage error signal VPI acquired in the first half cycle and the voltage error signal VPI acquired in the second half cycle.

  In step S207, the control unit 15 determines whether or not the calculated absolute value exceeds the first specified value by the VPI difference determination unit 44. When the calculated absolute value is equal to or less than the first specified value (step S207: YES), the control unit 15 determines that the corrected correction coefficient value is appropriate (that is, the harmonic current is within the allowable range), Proceed to step S208. On the other hand, when the calculated absolute value exceeds the first specified value (step S207: NO), the control unit 15 determines that the corrected correction coefficient value is not appropriate (that is, the harmonic current is outside the allowable range). Then, the process proceeds to step S209.

  In step S208, when it is determined in step S207 that the corrected correction coefficient value is appropriate, the control unit 15 increments the specified value determination count n by one. After the control unit 15 increments the specified value determination count n by 1, the process proceeds to step S209.

  In step S209, the control unit 15 determines whether or not the specified value determination count n is equal to or greater than a specified value. When the expected value determination count n is equal to or greater than the second specified value (step S209: YES), the control unit 15 proceeds to step S210. On the other hand, when the expected value determination count n is less than the second specified value (step S209: NO), the control unit 15 proceeds to step S201. The second specified value is a threshold value of the expected value determination number n for determining the corrected correction coefficient.

Here, as the second specified value is larger, the number of times that the absolute value is determined to be less than or equal to the first specified value in step S207 increases, and the correction coefficient for making the absolute value less than or equal to the first specified value. Increases accuracy. This means that the above-described waveform imbalance between the positive side and the negative side in one cycle of the input current can be stably improved. Therefore, in the present embodiment, the second specified value is set according to the accuracy of the required correction coefficient. However, the present invention is not limited to this example, and the second specified value is a value that can be set arbitrarily as long as the imbalance of the waveform can be improved.
In step S210, the control unit 15 determines the correction coefficient (K _neg or K _pos ) corrected in step S204 or step S205, and ends the input current correction process.

As described above, according to the present embodiment, the control unit 15 measures the difference value between the voltage error signal (+) generated in the first half cycle and the voltage error signal (−) generated in the second half cycle. If the measured difference value exceeds the first specified value, the correction coefficient k3 is corrected every half cycle so that the input current is balanced. FIG. 5 is a diagram illustrating an example of waveforms of the input voltage and the input current after correction of the correction coefficient. As shown in FIG. 5, the control unit 15 corrects the correction coefficient k3 based on the difference value, so that the input current waveform becomes a positive / negative target in the first half cycle and the second half cycle.
As a result, in the measurement circuit of the input current measurement value Iin, which is a separate circuit on the positive side and the negative side of the input current, the control unit 15 is caused by differences in errors such as component variations of each measurement circuit. The imbalance of the generated input current waveform can be suppressed, and the harmonic current can be prevented from increasing.

  You may make it implement | achieve the control part 15 in embodiment mentioned above with a computer. In that case, a program for realizing this function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be read into a computer system and executed. Here, the “computer system” includes an OS and hardware such as peripheral devices. The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory inside a computer system serving as a server or a client in that case may be included and a program held for a certain period of time. Further, the program may be a program for realizing a part of the above-described functions, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system. You may implement | achieve using programmable logic devices, such as FPGA (Field Programmable Gate Array).

The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes changes and the like without departing from the gist of the present invention.
In the present embodiment, the bridgeless boost type PFC control in which a full-wave rectifier circuit such as a diode bridge circuit is not connected to the AC power supply has been described. However, the present invention is applied to a diode bridge system using a diode bridge circuit. Of course it is also possible.

DESCRIPTION OF SYMBOLS 1a, 1b ... AC input terminal 2a, 2b ... DC output terminal FLTR ... Filter circuit RY ... Relay circuit L1, L2 ... Inductor D1, D2 ... Diode Q1, Q2 ... Transistor BD1, BD2 ... Diode R1, R2, R3 ... Resistor C2 ... Electrolytic capacitor 10 ... Power factor correction circuit 11 ... Input voltage detection unit 12 ... Input current detection unit 13 ... Switch drive unit 14 ... Output voltage detection unit 15 ... Control unit Vdc ... Output voltage measurement value Iin ... Input current measurement value Vin ... Input voltage measurement value 21 ... voltage error signal generator 22 ... current error signal generator 23 ... duty calculator 24 ... offset calculator 26 ... VPI generator 27 ... IPI generators 31, 32, 33 ... normalization calculator 41, 43 ... Comparator 42 ... Multiplier 44 ... VPI difference determination unit Vref ... Target output voltage value Ev ... Voltage difference value Gv ... Voltage gain,
VPI ... Voltage error signal Iref ... Input current set value Ei ... Current difference value Gi ... Current gain IPI ... Current error signal DUTY ... Time ratio TH ... First threshold value THoffset ... Second threshold value Offset ... Offset value

Claims (7)

An AC / DC converter comprising at least a switching element, an inductor and a diode for obtaining a DC voltage from the AC voltage of the AC power source;
An input voltage detector for detecting a voltage value of the AC power supply;
An input current detection unit for detecting a current value of the AC power supply;
An output voltage detection unit for detecting a voltage value of a DC voltage output by the AC / DC conversion unit;
Based on the current value of the AC power source, the voltage value of the AC power source and the voltage value of the DC voltage obtained by the input current detection unit, the input voltage detection unit, and the output voltage detection unit, respectively, the voltage value of the DC voltage A control unit that controls on / off of the switching element so that becomes a preset target output voltage value,
The controller is
A voltage error signal is generated from a voltage difference value between the voltage value of the DC voltage and the target output voltage value every half cycle of the AC voltage of the AC power supply, and the input current detection is performed based on the value of the voltage error signal A power supply apparatus that corrects a current value detected every half cycle by a unit.   When the absolute value of the difference value between the voltage error signal generated in the first half cycle of the AC voltage of the AC power supply and the voltage error signal generated in the second half cycle exceeds the specified value, the control unit The power supply device according to claim 1, wherein the current value detected by the input current detection unit is multiplied by a coefficient in either a half cycle or the latter half cycle. The controller is
A voltage error signal generator for generating a voltage error signal obtained by multiplying the pressure gain electric voltage difference between the voltage value and the target output voltage value of the DC voltage,
Based on the value of the voltage error signal generated in the voltage error signal generation unit, a difference determination unit that corrects the current value detected every half cycle by the input current detection unit;
A multiplier that generates an input current setting value based on the voltage value of the AC power supply and the voltage error signal;
A current error signal generation unit that generates a current error signal by performing PID calculation processing based on a current difference value between the input current setting value and the current value of the AC power supply;
A duty calculator for calculating a duty of a signal for controlling on / off of the switching element based on the current error signal;
An offset calculation unit that generates an offset value in the duty calculation unit based on a difference between the voltage error signal and a threshold value of the on / off control;
I have a,
The power supply apparatus according to claim 1 , wherein the voltage gain is obtained by the PID calculation process . The controller is
In the duty operation unit, the current error signal IPI which has been determined by the PID operation processing,
The duty ratio DUTY is
DUTY = Dmax−IPI × Kcnv (Dmax is a maximum output value (upper limit value) of the duty ratio DUTY, and Kcnv is a coefficient for converting the current error signal IPI into the duty ratio DUTY).
The power supply device according to claim 3, wherein the power supply device performs calculation. The PID calculation process in the current error signal generation unit is:
The current difference value Ei (t) is
Ei (t) = input current setting value Iref−input current measurement value Iin (t)
Is calculated by
The current error signal IPI = Ui (t) obtained by the PID calculation process is
Ui (t) = Kip × Ei (t) + {Kii × Ei (t−1) + Ui (t−1)} + Kid × {Ei (t) −Ei (t−n)}
(Ui (t−1) is the current error signal IPI obtained in the previous PID calculation process, and Ei (t−1) and Ei (t−n) are respectively one time before and n times before. The current difference value Ei in the PID calculation process is shown, Ei (t) is a value based on the result of the current process, and Kip, Kii, and Kid are proportional (P) coefficient and integral in the PID calculation process, respectively. (I) coefficient, differential (D) coefficient.
The power supply device according to claim 4, wherein the calculation is performed by: AC voltage detection process in which the input voltage detector detects the voltage value of the AC power supply;
An input current detection unit detects the current value of the AC power supply AC current detection process,
A DC voltage detection process in which an output voltage detection unit detects a voltage value of a DC voltage output by an AC / DC conversion unit including at least a switching element, an inductor, and a diode to obtain a DC voltage from the AC voltage of the AC power source;
The control unit is configured to control the direct current based on the current value of the alternating current power source, the voltage value of the alternating current power source, and the voltage value of the direct current voltage obtained by the input current detection unit, the input voltage detection unit, and the output voltage detection unit, respectively. A control process for controlling on / off of the switching element so that the voltage value of the voltage becomes a preset target output voltage value,
The control process is
A voltage error signal is generated from a voltage difference value between the voltage value of the DC voltage and the target output voltage value every half cycle of the AC voltage of the AC power supply, and the input current detection is performed based on the value of the voltage error signal And a step of correcting the current value detected every half cycle in the unit. Computer
AC voltage detection means for detecting the voltage value of the AC power supply by the input voltage detection unit,
AC current detection means, wherein the input current detection unit detects the current value of the AC power supply,
DC voltage detection means for detecting the voltage value of the DC voltage output by the AC / DC converter comprising at least a switching element, an inductor and a diode, wherein the output voltage detector obtains a DC voltage from the AC voltage of the AC power source,
The control unit is configured to control the direct current based on the current value of the alternating current power source, the voltage value of the alternating current power source, and the voltage value of the direct current voltage obtained by the input current detection unit, the input voltage detection unit, and the output voltage detection unit, respectively. Function as a control means for controlling the on / off of the switching element so that the voltage value of the voltage becomes a preset target output voltage value,
The control means includes
A voltage error signal is generated from a voltage difference value between the voltage value of the DC voltage and the target output voltage value every half cycle of the AC voltage of the AC power supply, and the input current detection is performed based on the value of the voltage error signal Means for correcting the current value detected every half cycle in the unit,
Control program for power supply to function as

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