TWI873048B - Power factor correction device and voltage output control method - Google Patents

Abstract

A voltage output control method is performed by a power factor correction device electrically connected to a voltage conversion circuit, and the voltage conversion circuit is electrically connected to an AC signal source that generates an AC signal and a load. The main technology is: the power factor correction device reads measurement data from the voltage conversion circuit and the AC signal source, and generates a signal start angle parameter and a signal turn-on angle parameter according to the measurement data. The signal turn-on angle parameter is related to the turn-on time of the control signal, and the turn-on time corresponds to the phase change of the AC signal. The power factor correction device generates a signal start angle parameter control signal according to the signal start angle parameter and the signal turn-on angle parameter, and sends it to the voltage conversion circuit.

Description

Power factor correction device and voltage output control method

The present invention relates to a power conversion device, and more particularly to a device and method for improving the power factor of a power source.

The voltage conversion circuit adjusts the power factor through the ratio of the capacitor and inductor in the circuit, and adjusts the current and voltage waveforms output by the power supply to the load through the transistor switch, corrects the phase of the current and the phase of the voltage, so that the power output by the power supply can effectively act on the load, thereby increasing the power acting on the load and improving the power factor. The control of the transistor switch controls the opening and closing time of the transistor switch through the pulse width modulation signal, and then adjusts the input current to synchronize with the input voltage, thereby adjusting the phase between the input voltage and current.

Refer to Figure 1. A control (VT) signal is continuously output and controls the transistor switch, causing the current waveform output to the load to be saw-toothed. The load generates non-ideal noise due to the current fluctuation, and the repeated switching causes the overall temperature to rise, thus affecting the circuit performance.

Therefore, the purpose of the present invention is to provide a method for effectively reducing the number of switch triggering times, thereby reducing the generation of undesirable noise, so as to enable a more efficient pulse width modulation signal control method.

Therefore, the voltage output control method of the present invention is performed by a power factor correction device electrically connected to a voltage conversion circuit, and the voltage conversion circuit is electrically connected to an AC signal source that generates an AC signal and a load. The voltage output control method includes the following steps:

(A) The power factor correction device reads a measurement data from the voltage conversion circuit and the AC signal source. The measurement data is related to the voltage and current values of the voltage conversion circuit and includes an AC voltage value, a load voltage value, and a load current value.

(B) The power factor correction device generates an AC voltage parameter according to the AC voltage value, generates a DC voltage parameter according to the load voltage value, and generates a load current parameter according to the load current value from the measured data read.

(C) The power factor correction device generates a signal starting angle parameter according to the load current parameter, and generates the signal opening angle parameter according to the AC voltage parameter and the DC voltage parameter, the signal starting angle parameter is related to a starting time point of a control signal, the starting time point corresponds to a phase angle of the AC signal, the signal opening angle parameter is related to a starting time of the control signal, and the starting time corresponds to a phase change of the AC signal.

(D) The power factor correction device generates a control signal according to the signal starting angle parameter and the signal opening angle parameter, and sends it to the voltage conversion circuit.

Another object of the present invention is to provide a power factor correction device applicable to a voltage conversion circuit, the voltage conversion circuit is electrically connected to the power factor correction device and is composed of first to fourth diodes, a transistor switch, an inductor, a capacitor, and an output diode. The power factor correction device includes a storage module, a sensing module, a signal generation module, and a processing module.

The storage module stores a current reference table data, and the current reference table data is related to the current value expected to flow through the load.

The sensing module is electrically connected to the voltage conversion circuit, and measures the voltage conversion circuit to generate a measurement data.

The signal generating module is electrically connected to the voltage conversion circuit and is used to generate a control signal.

The processing module is electrically connected to the sensing module, the storage module, and the signal generating module.

The effect of the present invention is that: the power factor correction device executes the voltage output control method, the measurement data is read from the voltage conversion circuit, and the signal starting angle parameter and the signal opening angle parameter are generated according to the measurement data, so that the control signal can reduce the number of times the transistor switch is triggered but still effectively control the voltage output and reduce the generation of non-ideal noise.

Before the present invention is described in detail, it should be noted that similar components are represented by the same reference numerals in the following description.

Referring to FIG. 2 , the voltage output control method of the present invention, also known as an embodiment of an active power factor correction (AFPC) method, is performed by a power factor correction device 100 electrically connected to a voltage conversion circuit 9. The voltage conversion circuit 9 is electrically connected to an AC signal source 8 generating an AC signal and a load 7, and is composed of first to fourth diodes D1 to D4, a transistor switch M1, an inductor L1, a capacitor C1, and an output diode D5. The transistor switch M1 can include but is not limited to a metal oxide semi-conductor field effect transistor (MOSFET) and a bipolar junction transistor (BJT) to achieve, and the present invention is not limited thereto.

The load 7 is a motor, and the motor output power is set according to the requirement.

The power factor correction device 100 includes a storage module 1, a sensing module 2 electrically connected to the voltage conversion circuit 9, a signal generating module 3 electrically connected to the voltage conversion circuit 9, and a processing module electrically connected to the sensing module 2, the storage module 1, and the signal generating module 3.

The sensing module 2 is used to sense the AC signal generated by the AC signal source 8 and the voltage and current of the load 7, and electrically connects the AC signal source 8 with the node of the voltage conversion circuit 9, and electrically connects the load 7 with the node of the voltage conversion circuit 9.

The signal generating module 3 is electrically connected to the transistor switch M1 and is used to generate a control signal, which is a pulse width modulation signal.

The storage module 1 stores a switch time parameter, a current reference table data, a voltage difference comparison table, and a current difference comparison table. The switch time parameter is related to the sensing module 2 periodically updating the opening time point and duration of the transistor switch M1. For example, it is set to update once per second, but the present invention is not limited to this. The current reference table data is related to the design of the load 7 (i.e., the motor) and the current value expected to flow at different speeds of the motor. The voltage difference comparison table and the current difference comparison table are described in detail later.

The processing module 4 can be implemented by a central processing unit (CPU), and the storage module 1 can be implemented by a memory. The CPU includes but is not limited to a single-core processor, a multi-core processor, a dual-core mobile processor, a microprocessor, a microcontroller, a digital signal processor (DSP), a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), a radio frequency integrated circuit (RFIC), etc. The memory can be implemented using a random access memory (RAM), a read-only memory (ROM), a programmable ROM (PROM), firmware and/or a flash memory, etc.

The operation details of the power factor correction device 100 in this embodiment will be explained below by using the voltage output control method.

Referring to FIG. 3 , the voltage output control method includes the following steps:

Step (A): The processing module 4 generates a sampling instruction, and the sampling instruction is used to instruct the sensing module 2 to read a measurement data from the voltage conversion circuit 9. The measurement data is related to the voltage and current values of the voltage conversion circuit 9, and includes an AC voltage value, a load voltage value, a load current value, and a DC peak-to-peak value. The AC voltage value is defined as the voltage value of the AC signal generated by the AC signal source 8, the load voltage value is defined as the voltage value of the load 7 of the voltage conversion circuit 9, and the load current value is defined as the current on the load 7. The DC peak-to-peak value is defined as the difference between the maximum and minimum voltage values of the load voltage.

Step (B): In the power factor correction device 100, the processing module 4 generates an AC voltage parameter according to the AC voltage value, generates the DC voltage parameter according to the load voltage value, and generates the load current parameter according to the load current value from the measured data read. The AC voltage parameter is related to the ratio of the AC voltage value to a target AC voltage, and the DC voltage parameter is related to a voltage difference, which is the difference between the load voltage value and a preset DC voltage value. The preset DC voltage value is related to the back electromotive force that needs to be overcome when the motor is running. The back electromotive force is the driving voltage required for the motor to reach a specific number of revolutions according to the specifications of the motor. For example, if the required speed of the motor is 60RPS, the required driving voltage is 160V according to the motor specifications, which means that the driving voltage must be at least 160V. The default DC voltage value is set to 1.2 times the driving voltage, i.e. 160×1.2=192V, considering the circuit driving capacity. The above describes the setting of the default DC voltage value, and the present invention is not limited to this embodiment.

The load current parameter is related to a current difference, which is the difference between the load current value and a rated target current. The rated target current is defined as the target current value corresponding to the speed required when the motor is running.

Referring to FIG. 4 , the step (B) includes sub-steps (B1) to (B3).

Sub-step (B1): The processing module 4 searches for the rated target current corresponding to the motor speed from the current reference table data of the storage module according to the motor speed, and calculates the difference between the rated target current and the load current value, and obtains the current difference. The processing module 4 reads the current difference comparison table (such as Table 1) in the storage module, and searches for the load current parameter corresponding to the range where the voltage difference is located according to the current difference comparison table. Table 1 Current difference Load current parameter value Greater than 5(A) A1 Greater than 3(A) B1 0 0 Less than 3 (A) C1 Less than 5(A) D1

Sub-step (B2): The processing module 4 generates a voltage RMS value according to the AC voltage value, and calculates the ratio of the voltage RMS value to a target AC voltage, the target AC voltage being related to the mains voltage value used for the load 7. The processing module 4 calculates the AC voltage parameter according to Formula 1:

G _ACV =220/V _AC ...Formula 1

Wherein, the G _ACV is the AC voltage parameter, the V _AC is the voltage RMS value, and the target AC voltage is set to 220V, that is, the AC signal source 8 is the mains voltage, and its voltage value is 220V, but the present invention is not limited thereto.

Sub-step (B3): The processing module 4 generates a load 7 voltage RMS value according to the load voltage value, and calculates the difference between the load 7 voltage RMS value and the preset DC voltage value, and obtains the voltage difference. The processing module 4 reads the voltage difference comparison table (such as Table 2) in the storage module, and searches for the DC voltage parameter corresponding to the interval where the voltage difference is located according to the voltage difference comparison table. Table 2 Voltage difference DC voltage parameter value Greater than 10(V) A2 Greater than 5(V) B2 0 0 Less than 5(V) C2 Less than 10(V) D2

Step (C): The power factor correction device 100 generates a signal start angle parameter according to the load current parameter, and generates the signal turn-on angle parameter according to the AC voltage parameter and the DC voltage parameter, as shown in FIG6 . The signal start angle parameter is related to a turn-on time point of the control signal (i.e., the pulse width modulation signal), and the turn-on time point corresponds to a phase angle of the AC signal. The signal turn-on angle parameter is related to a turn-on time of the control signal, and the turn-on time corresponds to a phase change of the AC signal.

The signal starting angle parameter is generated as shown in Formula 2:

A _ST = _{TS_DEF} + G _LC ...Formula 2

Among them, parameters A _ST , _{TS_DEF} , and G _LC are respectively the signal starting angle parameter, a starting angle constant, and the load current parameter. The starting angle constant is defined as setting the initial value of the signal starting angle parameter according to the design requirements of the load 7, which means the minimum phase angle of the AC signal opened by the control signal.

The signal starting angle parameter is generated as shown in Formula 3:

A _SZ = T _{D_DEF} × G _ACV + G _DCP × V _PP …Formula 3

Among them, parameter _ASZ is the signal turn-on angle parameter, parameter _{TD_DEF} is an turn-on angle constant, parameter G _ACV is the AC voltage parameter, parameter G _DCP is the DC voltage parameter, and parameter V _PP is the DC peak-to-peak value. The turn-on angle constant is defined as setting the initial value of the signal turn-on angle parameter according to the design requirements of the load 7, which means the minimum value of the turn-on time of the control signal.

Step (D): The power factor correction device 100 generates the control signal according to the signal start angle parameter and the signal opening angle parameter, and sends it to the transistor switch M1 of the voltage conversion circuit 9.

Referring to FIG. 5 , step (D) includes sub-steps (D1) and (D2).

Sub-step (D1): The processing module 4 determines whether the AC signal reaches the desired opening angle according to the signal starting angle parameter, and generates a determination result.

Sub-step (D2): When the judgment result is yes, the processing module 4 generates a control signal information according to the signal opening angle parameter and transmits it to the signal generating module 3. The control signal information is used to instruct the signal generating module 3 to generate the corresponding control signal and send it to the transistor switch M1.

In summary, by means of the sensing module 2 and the signal start angle parameter and the signal opening angle parameter generated by the processing module 4, the power factor can be effectively corrected while limiting the output of the control signal, thereby reducing the triggering times of the transistor switch M1, thereby reducing the non-ideal noise input to the load 7 and reducing the circuit temperature increase caused by repeated switching.

However, the above is only an example of the implementation of the present invention, and it should not be used to limit the scope of the implementation of the present invention. All simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the content of the patent specification are still within the scope of the patent of the present invention.

100: Power factor correction equipment 1: Storage module 2: Sensing module 3: Signal generation module 4: Processing module 7: Load 8: AC signal source 9: Voltage conversion circuit D1: First diode D2: Second diode D3: Third diode D4: Fourth diode D5: Output diode L1: Inductor C1: Capacitor M1: Transistor switch A~D: Power factor correction step B1~B3: Sub-step of generating parameters D1~D2: Sub-step of generating control signal

Other features and effects of the present invention will be clearly presented in the embodiment with reference to the diagrams, wherein: FIG. 1 is a timing diagram illustrating a known pulse width modulation signal input to a voltage conversion circuit, which outputs a current waveform of a load; FIG. 2 is a block diagram illustrating the structure of an embodiment of the power factor correction device of the present invention; FIG. 3 is a flow chart illustrating the embodiment executing a voltage output control method. FIG. 4 is a flow chart illustrating the embodiment generating a load current parameter, an AC voltage parameter, and a DC voltage parameter. FIG. 5 is a flow chart illustrating the embodiment generating a control signal method. FIG6 is a timing diagram illustrating an AC signal input to a voltage conversion circuit of the embodiment, which outputs a current waveform of a load.

100: Power factor correction equipment

1: Storage module

2:Sensor module

3:Signal generation module

4: Processing module

7: Load

8: AC signal source

9: Voltage conversion circuit

D1: First diode

D2: Second diode

D3: The third diode

D4: The fourth second pole

D5: output diode

L1: Inductor

C1: Capacitor

M1: Transistor switch

Claims (10)

A voltage output control method is performed by a power factor correction device electrically connected to a voltage conversion circuit, wherein the voltage conversion circuit is electrically connected to an AC signal source that generates an AC signal and a load, and the voltage output control method comprises: (A) the power factor correction device reads a measurement data from the voltage conversion circuit and the AC signal source, the measurement data is related to the voltage and current values of the voltage conversion circuit, and includes an AC voltage value, a load voltage value, and a load current value; (B) The power factor correction device generates an AC voltage parameter according to the AC voltage value, generates a DC voltage parameter according to the load voltage value, and generates a load current parameter according to the load current value from the measured data read; (C) The power factor correction device generates a signal starting angle parameter according to the load current parameter, and generates the signal opening angle parameter according to the AC voltage parameter and the DC voltage parameter, the signal starting angle parameter is related to a start time point of a control signal, the start time point corresponds to a phase angle of the AC signal, the signal opening angle parameter is related to a start time of the control signal, and the start time corresponds to a phase change of the AC signal; (D) The power factor correction device generates a control signal according to the signal starting angle parameter and the signal opening angle parameter, and sends it to the voltage conversion circuit. In the voltage output control method as described in claim 1, the AC voltage value is defined as the voltage value of the AC signal generated by the AC signal source of the voltage conversion circuit, the load voltage value is defined as the voltage value of the load of the voltage conversion circuit, the load current value is defined as the current on the load, and the AC voltage parameter is defined as the ratio of the AC voltage value to a target AC voltage, and the target AC voltage is related to the AC voltage value preset for the load. The DC voltage parameter is related to a voltage difference, which is the difference between the load voltage value and a preset DC voltage value. The preset DC voltage value is defined as a desired voltage value set according to the demand of the load. The load current parameter is related to a current difference, which is the difference between the load current value and a rated target current. The rated target current is defined as the target current value corresponding to the power required when the load is operating. A voltage output control method as described in claim 2, wherein the power factor correction device generates the current difference according to the difference between the load current value and the rated target current, and the current difference corresponds to different load current parameters; the power factor correction device generates a load square root mean voltage value according to the load voltage value, and calculates the difference between the load square root mean voltage value and a preset DC voltage value to generate the voltage difference, and the voltage difference corresponds to different DC voltage parameters. A voltage output control method as described in claim 2, wherein the signal starting angle parameter is generated as follows: A _ST = _{TS_DEF} +G _LC , wherein parameters A _ST , T _{S_DEF} , and G _LC are respectively the signal starting angle parameter, a starting angle constant, and the load current parameter, and the starting angle constant is defined as setting the initial value of the signal starting angle parameter according to the design requirements of the load, which indicates the minimum phase angle of the AC signal at which the control signal is turned on. A voltage output control method as described in claim 2, wherein the measurement data further includes a DC peak-to-peak value, the DC peak-to-peak value is defined as the difference between the maximum voltage value and the minimum voltage value of the load voltage value, and the signal starting angle parameter is generated as follows: _ASZ = _{TD_DEF} × G _{ACV + G DCP × V PP, wherein parameter ASZ is the signal turn-on angle parameter, parameter TD_DEF is an turn-on angle constant, parameter G ACV is the AC voltage parameter, parameter G DCP is the DC voltage parameter} , and parameter V _PP is the DC peak-to-peak value, and the turn-on angle constant is defined as setting the initial value of the signal turn-on angle parameter according to the design requirements of the load, which represents the minimum value of the turn-on time of the control signal. A voltage output control method as described in claim 3, wherein the power factor correction device stores a current reference table data, a current difference comparison table, and a voltage difference comparison table, wherein the current reference table data is related to the current value expected to flow through the load, the current difference comparison table is related to the load current parameter corresponding to the current difference, and the voltage difference comparison table is related to the DC voltage parameter corresponding to the voltage difference. The voltage output control method as described in claim 2, wherein the step (D) further comprises: (D1) the power factor correction device determines whether the AC signal reaches the desired opening angle and generates a determination result; (D2) when the determination result is yes, the power factor correction device generates the control signal according to the signal opening angle parameter and sends it to the voltage conversion circuit. A power factor correction device is electrically connected to a voltage conversion circuit, the voltage conversion circuit is electrically connected to an AC signal source that generates an AC signal and a load, and is composed of first to fourth diodes, a transistor switch, an inductor, a capacitor, and an output diode, and the power factor correction device includes: A storage module that stores a current reference table data, the current reference table data is related to the current value expected to flow through the load; A sensing module that is electrically connected to the voltage conversion circuit and measures the voltage conversion circuit and generates a measurement data; A signal generation module that is electrically connected to the voltage conversion circuit and is used to generate a control signal; and A processing module electrically connected to the sensing module, the storage module, and the signal generating module; wherein the power factor correction device reads a measurement data from the voltage conversion circuit, the measurement data is related to the voltage and current values of the voltage conversion circuit, and includes an AC voltage value, a load voltage value, and a load current value, the power factor correction device generates an AC voltage parameter according to the AC voltage value, a DC voltage parameter according to the load voltage value, and a load current parameter according to the load current value from the measurement data read, The power factor correction device generates a signal starting angle parameter according to the load current parameter, and generates the signal opening angle parameter according to the AC voltage parameter and the DC voltage parameter. The signal starting angle parameter is related to a start time point of a control signal, and the start time point corresponds to a phase angle of the AC signal. The signal opening angle parameter is related to a start time of the control signal, and the start time corresponds to a phase change of the AC signal. The power factor correction device generates a control signal according to the signal starting angle parameter and the signal opening angle parameter, and sends it to the voltage conversion circuit. In the power factor correction device as described in claim 8, the AC voltage value is defined as the voltage value of the AC signal generated by the AC signal source of the voltage conversion circuit, the load voltage value is defined as the voltage value of the load of the voltage conversion circuit, the load current value is defined as the current on the load, the AC voltage parameter is defined as the ratio of the AC voltage value to a target AC voltage, the target AC voltage is related to the preset AC voltage value of the load, the DC voltage parameter is related to a voltage difference, the voltage difference is the difference between the load voltage value and a preset DC voltage value, the preset DC voltage value is defined as the DC voltage value set according to the AC voltage parameter. The load current parameter is related to a current difference, which is the difference between the load current value and a rated target current. The rated target current is defined as the target current value corresponding to the power required when the load is in operation. The power factor correction device generates the current difference according to the difference between the load current value and the rated target current. The current difference corresponds to different load current parameters. The power factor correction device generates the voltage difference according to the difference between the load voltage value and a preset DC voltage value. The voltage difference corresponds to different DC voltage parameters. A power factor correction device as described in claim 9, wherein the measurement data further includes a DC peak-to-peak value, the DC peak-to-peak value is defined as the difference between the maximum voltage value and the minimum voltage value of the load voltage value, and the signal start angle parameter is generated as follows: _ASZ = _{TD_DEF} × G _ACV + G _DCP × V _PP wherein parameter ASZ is the signal turn-on angle parameter, parameter TD_DEF is a turn-on angle constant, parameter G _ACV is the AC voltage parameter, parameter G _DCP is the DC voltage parameter, and parameter V PP is the DC peak-to-peak value, the turn-on angle _constant is defined as setting the initial value of the signal turn-on angle parameter according to the design requirements of the load, that is, indicating the minimum value of the turn-on time of the control signal, and the signal start angle parameter is generated as follows: ASZ = TD_DEF × G ACV + G _DCP × V _PP wherein parameter ASZ is the signal turn-on angle parameter, parameter TD_DEF is a turn-on angle constant, parameter _{G ACV} is the AC voltage parameter, parameter G DCP is the DC voltage parameter, and parameter V PP is the DC peak-to-peak value. = _{TS_DEF} + _GLC wherein the parameters _AST , _{TS_DEF} , and _GLC are respectively the signal starting angle parameter, a starting angle constant, and the load current parameter. The starting angle constant is defined as setting the initial value of the signal starting angle parameter according to the design requirements of the load, which means the minimum phase angle of the AC signal opened by the control signal.