TWI636633B - Power quality control system - Google Patents

Abstract

A power quality control system includes a power supply end and a rectifying device. The power supply provides an alternating current. The rectifier device comprises an active front end rear stage module, an alternating current inductance measuring module, a direct current inductance measuring module, a microprocessor and a transmission unit. The active front-end rear-stage module converts the alternating current into a direct current and delivers the direct current to the load. The AC inductor module is used to sense an AC inductor signal. The DC inductor module is used to sense the DC sensor signal. The transmission unit is configured to receive and send a power demand request command, so that the microprocessor generates and sends a voltage modulation command to the active front end module according to the AC inductor test signal, the DC inductor test signal, and the power demand command. Adjust the power factor of the DC current.

Description

Power quality control system

The present invention relates to a power quality control system, which is a power quality control system that can perform power factor control.

Generally speaking, the power generated by power plants is transmitted to all parts of the country through the power grid, and in order to transmit power efficiently, it is usually transmitted in the form of alternating current. However, since the transmission of power is often affected by factors such as cable and distance, There is a problem with stability in the power system. In addition, about 70% of the electricity used in the country is industrial electricity, but the energy utilization rate of these industrial electricity is less than half, and these wasted energy mainly because the power grid is polluted. resulting in.

In the case of industrial electricity, because the grid will connect a large number of non-linear loads such as motors, inverters, rectifiers, uninterruptible power systems or voltage regulators in the plant, these non-linear loads will generate a large number of harmonics when these harmonics When the wave is transmitted back to the grid, the ineffective power of the power supplied by the grid will increase, which will result in the plant's equipment not being able to use the energy effectively. The existence of harmonics will not only cause energy waste, but also harmonics. Overheating the device shortens the life and even causes the device to burn out.

Referring to the first figure, the first figure shows a schematic diagram of using the power quality equipment to adjust the power quality of the grid supply to the load in the prior art. As shown in the figure, in the prior art, when the power grid PA1 delivers power to the load PA2, the load PA2 causes the power quality of the power grid PA1 to decrease, so in order to maintain the power quality of the power grid PA1 transmitted to the load PA2, usually in both A power quality device PA3 is provided for adjustment. The power quality device PA3 is, for example, a static type invalid power compensator (STATCOM), and the power quality device PA3 includes a plurality of capacitors PA31 (only one is shown) and a switch. The unit PA32 and a control unit PA33; wherein the switch unit PA32 is a circuit for controlling whether the plurality of capacitors PA31 are connected between the power grid PA1 and the load PA2.

When the control unit PA33 receives the power signal transmitted by the power sensor PA4, the control unit PA33 controls the number of circuits connected between the power supply PA1 and the load PA2 by the switching capacitor PA32 according to the demand of the power signal. Eliminate the harmonics of the power supply of the grid PA1. Although the power factor of the power supply PA1 to the load PA2 can be adjusted through the power quality device PA3, since the power quality device PA3 is adjusted by multi-stage power factor adjustment by the number of the conductive capacitors PA31, the load PA2 is actually The required power factor is likely to fall between every two stages of power. If the power is too high or too low, the instability of the power grid PA1 will occur, and even the power grid PA1 will collapse, which will result in waste of energy.

For example, since the power quality device PA3 adjusts the power factor by the conduction of the capacitor PA31, the power factor can be adjusted to 0.8, 0.85, 0.9, 0.95, or 1 at intervals of 0.05, so When the demand for power is 0.88, the power quality equipment PA3 will only adjust the power factor to 0.9, which will not adjust the power factor to optimize, which will result in waste of energy.

On the other hand, since there are usually many motor devices in the factory, and the motors of these motor devices are decelerating, the power is often returned to the inverter. Generally, in order to solve the problem of power regeneration, the resistors are used to consume energy. Off, but it is also prone to overheating problems, and in order to avoid the overheating problem that occurs when power is regenerated, the active front end power regenerative device (AFE) is used in the prior art to transfer the regenerative power to other The equipment is used, although the AFE can reduce the harmonic pollution generated by the inverter and increase the power factor to approach 1. However, in practice, most of the load needs do not need to reach 1, so when the AFE will work As it rises to approaching 1, it will require excessive discharge of capacitors, which will also cause waste of energy.

As mentioned above, although the power compensation method using STATCOM can adjust the power factor in stages, it cannot be accurately adjusted to meet the load factor requirements due to the segmentation compensation. If precise adjustment is required, The output of the capacitor must be divided into more segments, but it will increase the cost of the device; however, although the AFE can solve the problem of power regeneration, the AFE will directly increase the power factor to approach 1. There is a problem of energy waste.

In view of the prior art, whether it is a static type reactive power compensator (STATCOM) or an active front-end power regenerative device (AFE), it cannot effectively depend on the load or The user needs to adjust the power factor, so the power supply to the load of the power grid often exceeds the demand factor of the load, and thus the power is wasted due to excessively improved work; thus, the purpose of the present invention is to provide a power The quality control system is used to effectively improve the power quality of the power supply to the load through the control of the power factor.

In order to achieve the above object, the present invention provides a power quality control system including a power supply terminal and a rectifying device. The power supply is used to provide an alternating current.

The rectifying device comprises an active front end rear stage module, an alternating current electrical inductance measuring module, a direct current electrical sensing module, a microprocessor and a transmission unit.

The active front-end rear-stage module is electrically connected to the power supply end and a load end for converting the alternating current into a direct current and transmitting the direct current to the load end. The AC inductor module is disposed between the power supply end and the active front end module to sense an alternating current to generate an AC inductor test signal.

The DC inductance measuring module is disposed between the active front end rear stage module and the load end, and is used for sensing a DC current to generate a DC current measuring signal. The microprocessor is electrically connected to the AC inductor module, the active front-end module, and the DC inductor module for receiving the AC inductor signal and the DC inductor signal.

The transmission unit is electrically connected to the microprocessor for receiving a power demand signal carrying a target power factor value, and sending a power demand request command to the microprocessor, so that the microprocessor is based on the AC inductor test signal , DC inductance test signal and power demand command generated and sent a power The pressure modulation command is sent to the active front end rear stage module, so that the active front end rear stage module adjusts the power factor of the direct current to approach the target power factor value according to the voltage modulation command.

In an auxiliary technical means derived from the above-mentioned necessary technical means, the power quality control system further comprises an upper controller, which is communicatively coupled to the transmission unit for transmitting the power demand signal to the transmission unit.

Preferably, the power supply terminal further includes a power supply control device, which is communicatively coupled to the upper controller for transmitting the power demand signal to the transmission unit through the upper controller. The upper controller is communicatively coupled to a user control device for transmitting the power demand signal to the transmission unit under the control of the user control device.

In an auxiliary technical means derived from the above-mentioned necessary technical means, the microprocessor comprises a phase conversion unit, a power factor calculation unit, a comparator, a power factor controller and an active front end control module. The phase conversion unit is electrically connected to the AC inductance measurement module for converting the AC inductance measurement signal into a DC voltage value and a DC current value. The power factor calculation unit is electrically connected to the phase conversion unit, and calculates an AC power factor value according to the DC voltage value and the DC current value.

The comparator is electrically connected to the power factor calculation unit and the transmission unit for receiving the AC power factor value and the target power factor value, and calculating a power factor difference accordingly. The power factor controller is electrically coupled to the comparator for receiving the power factor difference and generating a voltage control command and a current control command accordingly. The active front-end control module is electrically connected to the power factor controller, the phase conversion unit, the DC inductor module, and the active front-end mode. Group, and calculate a voltage modulation rate according to the voltage control command, the current control command, the DC inductance test signal, the DC voltage value and the DC current value.

In an auxiliary technical means derived from the above-mentioned necessary technical means, the AC inductance measuring module further comprises a current sensor, a voltage sensor and an AC feedback circuit, and the current sensor is electrically connected to the power supply. The terminal is configured to sense an alternating current to generate a three-phase current signal, and the voltage sensor is electrically connected to the power supply end for sensing the alternating current to generate a three-phase voltage signal, and the alternating current feedback circuit is electrically connected. Connected to the current sensor, voltage sensor and microprocessor to transmit the three-phase current signal and the three-phase voltage signal to the microprocessor.

In an auxiliary technical means derived from the above-mentioned necessary technical means, the DC inductance measuring module further comprises a current sensor, a voltage sensor and a DC current feedback circuit, and the current sensor is electrically connected to the load end. And the active front-end rear-stage module is configured to sense a direct current to generate a DC current signal, and the voltage sensor is electrically connected to the load end and the active front-end rear-stage module for sensing a DC current to generate a continuous current. The voltage signal and the DC feedback circuit are electrically connected to the current sensor, the voltage sensor and the microprocessor to transmit the DC current signal and the DC voltage signal to the microprocessor.

As described above, the power quality control system of the present invention can transmit the target power factor value to the microprocessor, and the microprocessor can convert the three-phase current signal and the three-phase voltage signal sensed by the AC power sensor module into Two-phase voltage signal, and further calculating the AC power factor value of the AC current from the two-phase voltage signal, thereby calculating the power factor difference according to the target power factor value and the AC power factor value, so that the active front end control The module calculates the q-axis voltage modulation rate and the d-axis voltage modulation rate, and the active front-end rear-stage module can adjust the q-axis voltage modulation rate and the d-axis voltage when converting the alternating current into a direct current. The rate adjusts the power factor of the DC current to approach the target power factor.

PA1‧‧‧ grid

PA2‧‧‧ load

PA3‧‧‧Power quality equipment

PA31‧‧‧ capacitor

PA32‧‧‧Switch unit

PA33‧‧‧Control unit

PA4‧‧‧Power Sensor

100, 100a‧‧‧Power Quality Control System

1‧‧‧Power supply

11‧‧‧Power control device

12‧‧‧Power distribution unit

13‧‧‧Transformers

2, 2a, 2b‧‧‧ Rectifier

21‧‧‧Active front-end rear-end module

211a, 211b‧‧‧ coupling unit

212a, 212b‧‧‧reactance unit

213‧‧‧Amplification unit

214‧‧‧Capacitor unit

22‧‧‧AC Inductance Module

221‧‧‧ Current Sensor

222‧‧‧ voltage sensor

223‧‧‧AC feedback circuit

23‧‧‧DC Inductance Module

231‧‧‧ Current Sensor

232‧‧‧Voltage sensor

233‧‧‧DC feedback circuit

24‧‧‧Microprocessor

241‧‧‧ phase conversion unit

242‧‧‧Affinity calculation unit

243‧‧‧ comparator

244‧‧‧Power factor controller

245‧‧‧Active front-end control module

2451‧‧‧Voltage Control Unit

2452a, 2452b‧‧‧ Current Control Unit

2453a, 2453b‧‧‧Decoupling unit

2454a, 2454b‧‧‧ Modulation unit

i*qe‧‧‧current control command

25‧‧‧Transmission unit

3‧‧‧Upper controller

4‧‧‧User control device

200, 200a, 200b‧‧‧ load end

Iuvw‧‧‧Three-phase current signal

Vuvw‧‧‧ three-phase voltage signal

I _load ‧‧‧DC current signal

Vdc‧‧‧ DC voltage signal

Vqd‧‧‧ two-phase voltage signal

Iqd‧‧‧ two-phase current signal

Vqe‧‧‧q axis voltage value

Vde‧‧‧d axis voltage value

Iqe‧‧‧q axis current value

Ide‧‧‧d axis current value

PF-fbk‧‧‧ AC power factor

PF-cmd‧‧‧ target power factor

PF-err‧‧‧

V*dc‧‧‧Voltage Control Command

I*de‧‧‧current control command

Mq‧‧‧q axis voltage modulation rate

Md‧‧‧d axis voltage modulation rate

The first figure shows a schematic diagram of using the power quality device to adjust the power quality of the grid supply to the load in the prior art; the second figure shows a block diagram of the power quality control system provided by the preferred embodiment of the present invention; The figure shows a block diagram of a microprocessor provided by a preferred embodiment of the present invention; the fourth figure shows the logic circuit diagram of the active front end control module of the present invention; and the fifth figure shows the active front end rear stage module of the present invention. A logic circuit diagram; and a sixth diagram showing a block diagram of another power quality control system of the present invention.

Specific embodiments of the present invention will be described in more detail below with reference to the drawings. Advantages and features of the present invention will be apparent from the description and appended claims. It should be noted that the drawings are in a very simplified form and all use non-precision ratios. The purpose of the embodiments of the present invention is conveniently and clarified.

Please refer to the second and third figures. The second figure shows a block diagram of a power quality control system according to a preferred embodiment of the present invention. The third figure shows a microprocessor provided by a preferred embodiment of the present invention. Block diagram. As shown, a power quality control system 100 includes a power supply terminal 1, a rectifying device 2, an upper controller 3, and a user control device 4.

The power supply terminal 1 includes a power supply control device 11, a power distribution device 12, and a transformer 13. The power distribution device 12 is electrically connected to the power supply control device 11 and is monitored by the power supply control device 11. The transformer 13 is electrically connected to the power distribution device 12 and is used to transform and adjust the power provided by the power distribution device 12 to output an alternating current.

The rectifier device 2 includes an active front end module 21, an AC inductor module 22, a DC sensor module 23, a microprocessor 24, and a transmission unit 25.

The active front-end rear-stage module 21 is electrically connected to the transformer 13 of the power supply terminal 1 and a load terminal 200 for converting the alternating current provided by the power supply terminal 1 into a direct current and transmitting the direct current to the load. End 200.

The AC inductor module 22 is disposed between the transformer 13 of the power supply terminal 1 and the active front-end module 21, and includes a current sensor 221, a voltage sensor 222, and an AC feedback circuit 223. The current sensor 221 is configured to sense an alternating current to generate a three-phase current signal Iuvw. The voltage sensor 222 is configured to sense an alternating current to generate a three-phase voltage signal Vuvw. AC feedback circuit 223 is electrically connected The current sensor 221 and the voltage sensor 222 are configured to transmit the three-phase current signal Iuvw and the three-phase voltage signal Vuvw. In practice, the current sensor 221 is disposed in series between the transformer 13 and the active front end module 21, and the voltage sensor 222 is disposed in parallel with the transformer 13 and active. The circuit between the front-end rear stage modules 21.

The DC inductor module 23 is disposed between the active front end module 21 and the load terminal 200, and includes a current sensor 231, a voltage sensor 232, and a DC power feedback circuit 233. The current sensor 231 is configured to sense a direct current to generate a direct current signal I _load . The voltage sensor 232 is configured to sense a direct current to generate a DC voltage signal Vdc. The DC feedback circuit 233 is electrically connected to the current sensor 231 and the voltage sensor 232 for transmitting the DC current signal I _load and the DC voltage signal Vdc. In practice, the current sensor 231 is disposed in series between the active front end module 21 and the load terminal 200, and the voltage sensor 232 is disposed in parallel after the active front end. The circuit between the level module 21 and the load terminal 200.

The microprocessor 24 includes a phase conversion unit 241, a power factor calculation unit 242, a comparator 243, a power factor controller 244, and an active front end control module 245.

The phase conversion unit 241 is electrically coupled to the AC inductor module 22 for converting the three-phase voltage signal Vuvw into a two-phase voltage signal Vqd and converting the three-phase current signal Iuvw into a two-phase current signal Iqd. The two-phase voltage signal Vqd includes a q-axis voltage value Vqe and a d-axis voltage value Vde, and the two-phase current signal Iqd includes a q-axis current value iqe and a d-axis current value ide. In addition, in practice, phase conversion The unit 241 converts the three-phase voltage signal Vuvw and the three-phase current signal Iuvw into a two-phase voltage signal Vqd and a two-phase current signal Iqd through a Clarke conversion, respectively.

The power factor calculation unit 242 is electrically coupled to the phase conversion unit 241, and calculates an AC power factor PF-fbk according to the q-axis voltage value Vqe, the d-axis voltage value Vde, the q-axis current value iqe, and the d-axis current value ide. .

The comparator 243 is electrically coupled to the power factor calculation unit 242 and the transmission unit 25 for receiving the AC power factor value PF-fbk transmitted by the power factor calculation unit 242 and one of the target power factor values PF transmitted by the transmission unit 25. Cmd, and according to the calculation of the difference PF-err.

The power factor controller 244 is electrically coupled to the comparator 243 for receiving the power factor difference PF-err and generating a voltage control command V*dc and a current control command I*de.

The active front-end control module 245 is electrically connected to the power factor controller 244, the phase conversion unit 241, the DC-inductance module 23, and the active front-end module 21, and is based on the voltage control command V*dc and the current control command I. *de and the DC voltage signal Vdc calculate a q-axis voltage modulation rate Mq and a d-axis voltage modulation rate Md. The active front-end control module 245 transmits the q-axis voltage modulation rate Mq and the d-axis voltage modulation rate Md to the active front-end rear-stage module 21, so that the active front-end rear-stage module 21 is modulated according to the q-axis voltage. The power factor of the rate Mq and the d-axis voltage modulation rate Md is adjusted to approach the target power factor value.

The transmission unit 25 is electrically coupled to the comparator 243 of the microprocessor 24 for transmitting the target power factor value PF-cmd to the comparator 243.

The upper controller 3 is electrically connected to the transmission unit 25, And communicating with the power supply control device 11 and the user control device 4 of the power supply terminal 1 for receiving the power demand signal of the target power factor PF-cmd transmitted by the power supply control device 11 or the user control device 4 And the target power factor PF-cmd is transmitted to the microprocessor 24 via the transmission unit 25.

Please refer to the fourth figure. The fourth figure shows the logic circuit diagram of the active front end control module of the present invention. As shown, the active front end control module 245 includes a voltage control unit 2451, two current control units 2452a and 2452b, two decoupling units 2453a and 2453b, and two modulation units 2454a and 2454b.

The voltage control unit 2451 calculates a current control command i*qe according to the difference between the voltage control command V*dc and the DC voltage signal Vdc and the q-axis voltage value Vqe, and the current control unit 2452a is further based on the current control command i*qe, The DC current signal I _load and the q-axis current value iqe calculate a first gain value, and then the modulation unit 2454a further divides the first gain value, the d-axis voltage decoupling value calculated by the decoupling unit 2453b, and the q-axis voltage value. Vqe calculates the q-axis voltage modulation rate Mq; on the other hand, the current control unit 2452b calculates a second gain value according to the current control command i*de and the d-axis current value ide, and then the modulation unit 2454b is further The two gain values, the q-axis voltage decoupling value calculated by the decoupling unit 2453a, and the d-axis voltage value Vde calculate the d-axis voltage modulation rate Md. Among them, the fourth figure mainly shows the logical operation of calculating the d-axis voltage modulation rate Md and the q-axis voltage modulation rate Mq, and the symbols of the logical operations shown in the figure are symbols that can be understood by those having ordinary knowledge in the field. Therefore, no more rumors are added.

Please continue to refer to the fifth figure, the fifth figure shows the invention The logic circuit diagram of the active front-end rear-level module. As shown, the active front-end rear stage module 21 includes two coupling units 211a and 211b, two reactance units 212a and 212b, an amplifying unit 213, and a capacitor unit 214.

The coupling unit 211a couples the q-axis current value iqe to calculate a q-axis coupling value, and the coupling unit 211b couples the d-axis current value ide to calculate a d-axis coupling value, thereby subtracting the q-axis voltage value Vqe. The product of the d-axis coupling value and the q-axis voltage modulation rate Md and the DC voltage signal Vdc, and subtracts the d-axis voltage value Vde from the q-axis coupling value and the product of the d-axis voltage modulation rate Md and the DC voltage signal Vdc, after which Then, the boosting units 212a and 212b, the amplifying unit 213, and the capacitor unit 214 are integrated and amplified. Among them, the fifth figure mainly shows the operation of voltage modulation and amplification using the d-axis voltage modulation rate Md and the q-axis voltage modulation rate Mq, and the symbols of the logic operations shown in the figure are common knowledge in the field. Can understand the symbol, so no more rumors.

Please refer to the sixth figure, which is a block diagram showing another power quality control system of the present invention. As shown in the figure, a power quality control system 100a is electrically connected to the load terminals 200, 200a and 200b via the rectifying devices 2, 2a and 2b, respectively, compared to the power quality control system 100 described above. The power supply terminal 1 or the user control device 4 can perform power factor control on the rectifying devices 2, 2a and 2b via the upper controller 3, respectively.

In summary, the power quality control system 100 of the present invention can transmit the power factor demand signal carrying the target power factor value PF-cmd to the upper controller by the power supply control device 11 or the user control device 4 of the power supply terminal 1. 3, so that the host controller 3 will target the target factor value PF-cmd The microprocessor 24 can convert the three-phase current signal Iuvw and the three-phase voltage signal Vuvw sensed by the AC inductance measuring module 22 into a two-phase voltage signal Vqd, and further by a two-phase voltage. The signal Vqd calculates the AC power factor PF-fbk of the AC current, thereby calculating the power factor difference PF-err by comparing the target power factor PF-cmd with the AC power factor PF-fbk, so that the active front end control module 245 calculates the q-axis voltage modulation rate Mq and the d-axis voltage modulation rate Md, and the active front-end rear stage module 21 can convert the alternating current into the direct current according to the q-axis voltage modulation rate Mq and the d-axis. The voltage modulation rate Md adjusts the power factor of the direct current to approach the target power factor value.

As described above, in practice, the power supply terminal 1 is, for example, a power plant, and the power plant can set the target power factor value PF-cmd to 0.9 and transmit it to the rectifying device 2 via the host controller 3 to make the power plant When the AC current supplied is converted into a direct current by the rectifying device 2, the power factor of the direct current is adjusted to approach 0.9; on the other hand, when the power factor requirement of the load terminal 200 is 0.88, the user can pass the user. The control device 4 transmits a power factor demand signal with a target power factor value PF-cmd of 0.88 to the upper controller 3, so that the rectifier device 2 adjusts the power factor of the direct current to a value close to 0.88 according to the target power factor value PF-cmd. .

As can be seen from the above description, the power quality control system 100 can control the power factor when the AC current of the power supply terminal 1 is converted into the DC current to the load terminal 200 by the power supply control device 11 or the user control device 4 of the power supply terminal 1 The power factor of the direct current can be made closer to the power factor requirement of the load terminal 200. For example, the power supply terminal 1 can set the preset power factor provided by the user of the load terminal 200. The target power factor PF-cmd is set to enable the load terminal 200 to utilize power efficiently, or the user of the load terminal 200 directly sets the target power factor value PF-cmd through the user control device 4 to make the DC current The power factor is more accurate and close to the power factor requirement of the load terminal 200.

However, compared with the prior art static type reactive power compensator (STATCOM) or active front-end power regenerative device (AFE), the power factor cannot be effectively adjusted according to the load or the user's demand. The power factor is adjusted to approach 1 and the power is excessively wasted. The power quality control system of the present invention can adjust the power factor of the direct current according to the actual power requirement, in addition to preventing the power factor from being too low. The equipment on the load end is overheated and damaged, and the excessive waste of power can be effectively avoided.

The above is only a preferred embodiment of the invention and is not intended to limit the invention. Any changes in the technical means and technical contents disclosed in the present invention may be made by those skilled in the art without departing from the technical means of the present invention. The content is still within the scope of protection of the present invention.

Claims (7)

A power quality control system includes: a power supply end for providing an alternating current; and a rectifying device comprising: an active front end rear stage module electrically coupled to the power supply end and a load end, The AC current is converted to a DC current, and the DC current is transmitted to the load end; an AC inductance test module is disposed between the power supply end and the active front end rear stage module for Sensing the alternating current to generate an alternating current inductance test signal; the continuous current inductance measuring module is disposed between the active front end rear stage module and the load end for sensing the direct current to generate a direct current inductance test a microprocessor electrically coupled to the AC inductor module, the active front-end module, and the DC inductor module for receiving the AC inductor signal and the DC inductor signal; a transmission unit electrically coupled to the microprocessor for receiving a power demand signal carrying a target power factor value, and transmitting a power demand request command to the microprocessor to enable the micro The controller generates and sends a voltage modulation command to the active front end module according to the AC inductor test signal, the DC inductor test signal, and the power demand command, so that the active front end module is adjusted according to the voltage The variable command adjusts the power factor of the DC current to approach the target power factor value. The power quality control system of claim 1, further comprising an upper controller coupled to the transmission unit for transmitting the power demand signal to the transmission unit. The power quality control system of claim 2, wherein the power supply end further includes a power supply control device coupled to the upper controller for transmitting the power demand signal through the upper controller. To the transmission unit. The power quality control system of claim 2, wherein the upper controller is communicatively coupled to a user control device for transmitting the power demand signal to the user control device Transmission unit. The power quality control system of claim 1, wherein the microprocessor comprises: a phase conversion unit electrically coupled to the alternating current sensing module for converting the alternating current sense signal into a a DC voltage value and a DC current value; a power factor calculation unit is electrically coupled to the phase conversion unit, and calculates an AC power factor value according to the DC voltage value and the DC current value; a comparator is electrically Sexually connected to the power factor calculation unit and the transmission unit for receiving the AC power factor value and the target power factor value, and calculating a power factor difference accordingly; a power factor controller is electrically coupled to the comparator for receiving the power factor difference and generating a voltage control command and a current control command; and an active front end control module electrically connected The power factor controller, the phase conversion unit, the DC inductor module and the active front end module, and according to the voltage control command, the current control command, the DC inductor test signal, the DC voltage value and The DC current value calculates a voltage modulation rate. The power quality control system of claim 1, wherein the AC inductor module further includes a current sensor, a voltage sensor, and an AC feedback circuit, wherein the current sensor is electrically Connected to the power supply end for sensing the alternating current to generate a three-phase current signal, the voltage sensor is electrically connected to the power supply end for sensing the alternating current to generate a three-phase a voltage signal, the AC feedback circuit is electrically connected to the current sensor, the voltage sensor and the microprocessor, and is configured to transmit the three-phase current signal and the three-phase voltage signal to the microprocessor . The power quality control system of claim 1, wherein the DC inductor module further includes a current sensor, a voltage sensor, and a DC current feedback circuit, wherein the current sensor is electrically The current is connected to the load end and the active front end module to sense the DC current to generate a DC current signal. The voltage sensor is electrically connected to the load end and the active front end module. To sense the The DC current generates a DC voltage signal, and the DC feedback circuit is electrically connected to the current sensor, the voltage sensor and the microprocessor, and the DC current signal and the DC voltage signal are transmitted to the DC current signal The microprocessor.