CN117294114A - Three-phase four-wire PWM rectifier control method, device, equipment and storage medium - Google Patents

Abstract

The invention relates to a three-phase four-wire PWM rectifier control method, device, equipment and storage medium. The method includes: determining a current reference value based on the output voltage of the three-phase four-wire PWM rectifier and voltage outer loop parameters; based on the current inner loop loop, determine the current difference based on the AC side inductor current of the three-phase four-wire PWM rectifier and the current reference value; set the initial offset, and input the initial offset and the current difference to the PID controller Calculate the duty cycle to control the three-phase four-wire PWM rectifier. The present invention first determines the current reference value by controlling the designed voltage outer loop, and then determines the current difference value based on the designed current inner loop based on the current reference value and the AC side inductor current, and then sets the initial offset amount to determine the current offset value. Finally, only one PID controller can be used to adjust the AC side inductor current and output voltage of the three-phase four-wire PWM rectifier. The control algorithm is simple, the analysis process is simple, and it is suitable for engineering practice.

Description

A three-phase four-wire PWM rectifier control method, device, equipment and storage medium

Technical field

The present invention relates to the field of power electronics technology, and in particular to a three-phase four-wire PWM rectifier control method, device, equipment and storage medium.

Background technique

The three-phase PWM rectifier is a common power electronic device. Compared with the three-phase three-wire PWM rectifier, the three-phase four-wire PWM rectifier can better suppress the DC component of the input current, greatly improve the quality of the input current waveform, and further improve the rectifier's performance. Power factor, therefore, three-phase four-wire PWM rectifiers are being put into use more and more.

Currently, there are many control strategies for three-phase four-wire PWM rectifiers, such as single-cycle control, using virtual orthogonal transformation method to achieve zero static difference control of input current, using fractional-order repetitive control to suppress grid-side current harmonics, etc. These control strategies generally require two PID controllers or even three PID controllers to complete the control, which can produce better control results for a certain aspect of the PWM rectifier.

However, the current control strategy of the three-phase four-wire PWM rectifier requires multiple PID controllers to complete. The control algorithm is relatively complex and the analysis process is cumbersome. It cannot control the three-phase four-wire PWM rectifier in a timely manner, which is not conducive to engineering practice.

Contents of the invention

In view of this, it is necessary to provide a three-phase four-wire PWM rectifier control method, device, equipment and storage medium to solve the problem that the control of the three-phase four-wire PWM rectifier in the existing technology requires multiple PID controllers. As a result, the control algorithm is relatively complex, the analysis process is cumbersome, and the three-phase four-wire PWM rectifier cannot be controlled in a timely manner, which is not conducive to engineering practice.

In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

In a first aspect, the present invention provides a three-phase four-wire PWM rectifier control method, including:

Determine the current reference value based on the output voltage of the three-phase four-wire PWM rectifier and the voltage outer loop parameters;

Based on the current inner loop, the current difference is determined based on the AC side inductor current and current reference value of the three-phase four-wire PWM rectifier;

Set the initial offset, and input the initial offset and current difference to the PID controller to calculate the duty cycle to control the three-phase four-wire PWM rectifier.

In some possible implementations, the current reference value is determined based on the output voltage of the three-phase four-wire PWM rectifier based on the voltage outer loop, including:

Generate a duty cycle wavetable based on the duty cycle expression and the initial value of the autoload register of the microcontroller timer;

Set the phase offset and determine the current standard value based on the phase offset and the duty cycle wave table;

The output voltage is step-adjusted according to the wavetable coefficient and current standard value to determine the current reference value.

In some possible implementations, the duty cycle wavetable is generated based on the duty cycle expression and the initial value of the autoload register of the microcontroller timer, including:

The duty cycle expression is:

Among them, D is the duty cycle value, N is the number of values in the wave table, k is a specific value from 0 to N, and m is the modulation degree;

Determine the wavetable median value based on the initial value of the auto-load register of the microcontroller timer;

Generate a duty cycle wavetable based on the wavetable median value and the duty cycle expression.

In some possible implementations, the current standard value is determined based on the phase offset and duty cycle wavetable, including:

Determine the half cycle of the phase voltage;

Determine the wavetable index value according to the half-cycle and duty cycle wavetable where the phase voltage is located;

Determine the current standard value based on the wavetable index value and phase offset.

In some possible implementations, the output voltage is step-adjusted according to the wavetable coefficient and the current standard value to determine the current reference value, including:

Set initial wavetable coefficients;

If the initial wavetable coefficient does not meet the preset conditions, adjust the initial wavetable coefficient until the output voltage meets the preset voltage reference value and obtain the target wavetable coefficient;

Multiply the target wavetable coefficient and the current standard value to obtain the current reference value.

In some possible implementations, the initial bias and current difference are input to the PID controller to calculate the duty cycle to control the three-phase four-wire PWM rectifier, including:

Determine multiple consecutive current offset values based on the initial offset amount and current difference;

Based on the discrete expression of the PID controller, the duty cycle is calculated based on multiple current bias values;

The AC side inductor current and output voltage of the three-phase four-wire PWM rectifier are adjusted according to the duty cycle.

In some possible implementations, the discrete expression of the PID controller is as follows:

Δu(k)＝K _p [e _r (k)-e _r (k-1)]+K _i e _r (k)+K _d [e _r (k)-2e _r (k-1)+e _r (k-2)];

Among them, Δu(k) represents the duty cycle of the controller output, K _p , K _i , K _d represent the proportional, integral and differential gain coefficients respectively, e _r (k), e _r (k-1), e _r (k-2) respectively represent the k-th current offset value, the k-1-th current offset value and the k-2-th current offset value.

In a second aspect, the present invention also provides a three-phase four-wire PWM rectifier control device, including:

The voltage loop module is used to determine the current reference value based on the output voltage of the three-phase four-wire PWM rectifier and the voltage outer loop parameters;

The current loop module is used to determine the current difference based on the current inner loop based on the AC side inductor current and current reference value of the three-phase four-wire PWM rectifier;

The control module is used to set the initial offset and input the initial offset and current difference to the PID controller to calculate the duty cycle and control the three-phase four-wire PWM rectifier.

In a third aspect, the present invention also provides a three-phase four-wire PWM rectifier control device, including a memory and a processor, wherein,

Memory, used to store programs;

The processor is coupled to the memory and is used to execute the program stored in the memory to implement the steps in the three-phase four-wire PWM rectifier control method in any of the above implementations.

In a fourth aspect, the present invention also provides a computer-readable storage medium for storing computer-readable programs or instructions. When the programs or instructions are executed by the processor, the three-phase operation in any of the above implementations can be realized. Steps in the four-wire PWM rectifier control method.

The beneficial effects of adopting the above embodiments are: the present invention relates to a three-phase four-wire PWM rectifier control method, device, equipment and storage medium. The method includes: according to the output voltage and voltage outer loop parameters of the three-phase four-wire PWM rectifier Determine the current reference value; determine the current difference value based on the current inner loop, the AC side inductor current of the three-phase four-wire PWM rectifier and the current reference value; set the initial offset amount, and combine the initial offset amount and the current reference value. The current difference is input to the PID controller to calculate the duty cycle and control the three-phase four-wire PWM rectifier. This invention first determines the current reference value by controlling the designed voltage outer loop, and then determines the current difference based on the designed current inner loop based on the current reference value and the AC side inductor current, and then determines the current offset by setting the initial offset. value, successively through the double-loop closed control of the voltage outer loop and the current inner loop, and finally through only one PID controller, the AC side inductor current and output voltage of the three-phase four-wire PWM rectifier can be adjusted, reducing the need for a PID controller. Quantity makes the control algorithm simpler and the analysis process more concise, so it can be better put into engineering practice.

Description of drawings

Figure 1 is a schematic flow chart of an embodiment of a three-phase four-wire PWM rectifier control method provided by the present invention;

Figure 2 is a schematic structural diagram of an embodiment of a three-phase four-wire PWM rectifier control system provided by the present invention;

Figure 3 is a schematic flow chart of an embodiment of step S101 in Figure 1 provided by the present invention;

Figure 4 is a partial schematic diagram of an embodiment of the duty cycle wavetable provided by the present invention;

Figure 5 is a schematic flow chart of an embodiment of step S202 in Figure 2 provided by the present invention;

Figure 6 is a schematic flow chart of an embodiment of step S203 in Figure 2 provided by the present invention;

Figure 7 is a schematic flow chart of an embodiment of controlling a three-phase four-wire PWM rectifier provided by the present invention;

Figure 8 is a schematic structural diagram of an embodiment of a three-phase four-wire PWM rectifier bridge control device provided by the present invention;

Figure 9 is a schematic structural diagram of a three-phase four-wire PWM rectifier control device provided by an embodiment of the present invention.

Detailed ways

The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

In the description of this application, "plurality" means two or more than two, unless otherwise explicitly and specifically limited.

Reference herein to "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment can be included in at least one embodiment of the invention. The appearances of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those skilled in the art understand, both explicitly and implicitly, that the embodiments described herein may be combined with other embodiments.

The present invention provides a three-phase four-wire PWM rectifier control method, device, equipment and storage medium, which will be described separately below.

Please refer to Figure 1. Figure 1 is a schematic flow chart of an embodiment of a three-phase four-wire PWM rectifier control method provided by the present invention. A specific embodiment of the present invention discloses a three-phase four-wire PWM rectifier control method, including :

S101. Determine the current reference value based on the output voltage of the three-phase four-wire PWM rectifier and the voltage outer loop parameters;

S102. Based on the current inner loop, determine the current difference based on the AC side inductor current and current reference value of the three-phase four-wire PWM rectifier;

S103. Set the initial offset, and input the initial offset and current difference to the PID controller to calculate the duty cycle to control the three-phase four-wire PWM rectifier.

In the above embodiment, the three-phase four-wire PWM rectifier is a unified circuit, and its control needs to be implemented in the overall control system. Please refer to Figure 2. Figure 2 is a diagram of the three-phase four-wire PWM rectifier control system provided by the present invention. A schematic structural diagram of an embodiment. The output voltage of the three-phase four-wire PWM rectifier first passes through the voltage outer loop, is compared with the preset reference voltage, and is adjusted so that the output voltage gradually approaches the preset reference voltage and reaches the output voltage. Tracking the effect of the reference voltage, the current corresponding to the output voltage at this time is the current reference value.

It should be noted that the output voltage of the three-phase four-wire PWM rectifier in Figure 2 passes through the filter, is compared with the voltage reference value to obtain the changing voltage, and then passes through the voltage regulator to obtain the current reference value. This loop is the voltage outer loop loop. , the AC side inductor current of the three-phase four-wire PWM rectifier in Figure 2 is compared with the current reference value through the filter, and the loop that reaches the discrete PID controller through overcurrent protection is the current inner loop loop.

The current inner loop can control the AC side inductor current and keep the AC side inductor current constant. It controls the AC side inductor current of the three-phase four-wire PWM rectifier according to the current reference value output by the voltage outer loop to determine the AC side inductor current and current reference. The current difference between the values and transmits this difference as input to the PID controller.

The initial offset can be adjusted later and is input to the PID controller through the capacitor voltage equalizer in order to control the current difference and offset and adjust the duty cycle of the three-phase four-wire PWM rectifier to achieve By controlling the output voltage and AC side inductor current of the three-phase four-wire PWM rectifier, the actual AC side inductor current follows the current reference value in the wave table, and the input current is sinusoidal.

It should be noted that since the three-phase four-wire PWM rectifier has multiple phases, in order to control the three-phase four-wire PWM rectifier, a single phase needs to be controlled. Therefore, the present invention needs to construct the average of the three-phase four-wire PWM rectifier. The equivalent model is used to determine the relationship between each phase. According to the topology structure and switching mode of the three-phase four-wire PWM rectifier, the relationship between the bridge arm voltage and the DC side voltage is determined, and then the state equation of the three-phase four-wire PWM rectifier and the three The average duty cycle of the bridge arm is further deduced according to the switching cycle average method to obtain the average equivalent model of the three-phase four-wire PWM rectifier, thereby determining that each phase of the three-phase four-wire PWM rectifier circuit is independent of each other and is mutually independent. There is no coupling relationship between them, and the three-phase four-wire PWM rectifier circuit can be decomposed into three independent one-way full-bridge rectifiers.

It can be understood that the preset reference voltage and initial bias can be adjusted according to actual needs, and the present invention does not impose further limitations on this. As a preferred embodiment, the initial bias is artificially set to a constant (around 200), and then the PID controller will adjust on this basis during operation to reduce the voltage difference between the upper and lower tubes.

Compared with the existing technology, this embodiment provides a three-phase four-wire PWM rectifier control method. The method includes: determining the current reference value based on the output voltage of the three-phase four-wire PWM rectifier and the voltage outer loop parameters; The inner loop determines the current difference based on the AC side inductor current of the three-phase four-wire PWM rectifier and the current reference value; sets the initial offset, and inputs the initial offset and the current difference into the PID The controller calculates the duty cycle to control the three-phase four-wire PWM rectifier. This invention first determines the current reference value by controlling the designed voltage outer loop, and then determines the current difference based on the designed current inner loop based on the current reference value and the AC side inductor current, and then determines the current offset by setting the initial offset. value, successively through the double-loop closed control of the voltage outer loop and the current inner loop, and finally through only one PID controller, the AC side inductor current and output voltage of the three-phase four-wire PWM rectifier can be adjusted, reducing the need for a PID controller. Quantity makes the control algorithm simpler and the analysis process more concise, so it can be better put into engineering practice.

In order to achieve precise control of the three-phase four-wire PWM rectifier, the first step of control is carried out by designing the voltage outer loop. Please refer to Figure 3. Figure 3 is a flow diagram of an embodiment of step S101 in Figure 1 provided by the present invention. In In some embodiments of the present invention, based on the voltage outer loop, the current reference value is determined according to the output voltage of the three-phase four-wire PWM rectifier, including:

S301. Generate a duty cycle wavetable based on the duty cycle expression and the initial value of the automatic load register of the microcontroller timer;

S302. Set the phase offset, and determine the current standard value based on the phase offset and the duty cycle wave table;

S303. Stepwise adjust the output voltage according to the wave table coefficient and current standard value to determine the current reference value.

In the above embodiment, the initial value of the auto-loading register of the microcontroller timer is first set. The initial value of the auto-loading register of the microcontroller timer is related to the duty cycle and can be determined by the initial value of the auto-loading register of the microcontroller timer. The duty cycle wavetable realizes the adjustment of the current reference value output by the voltage outer loop, which is beneficial to the subsequent control of the current inner loop.

The phase offset Phase means that there will be a certain deviation in the currents of different phases. The accurate current standard value is determined by the set phase offset Phase, which is conducive to the adjustment and control of the voltage outer loop, thereby accurately determining the current reference value. It can be understood that the phase offset Phase can be adjusted according to the actual situation. The present invention does not further limit this. As a preferred embodiment, the value of the initially set phase offset Phase is 0, and can be adjusted according to the power factor. needs to be adjusted.

The wavetable coefficient also needs to be set to an initial value in advance. By multiplying the wavetable coefficient and the current standard value, the voltage outer loop can be adjusted stepwise in advance. Through subsequent adjustment of the wavetable coefficient, the output of the three-phase four-wire PWM rectifier can be adjusted. The voltage gradually approaches the preset reference voltage, and finally the voltage outer loop outputs the current reference value.

In some embodiments of the present invention, the duty cycle wavetable is generated according to the duty cycle expression and the initial value of the autoload register of the microcontroller timer, including:

The duty cycle expression is:

Among them, D is the duty cycle value, N is the number of values in the wave table, k is a specific value from 0 to N, and m is the modulation degree;

Determine the wavetable median value based on the initial value of the auto-load register of the microcontroller timer;

Generate a duty cycle wavetable based on the wavetable median value and the duty cycle expression.

In the above embodiment, the SPWM wave duty cycle expression is derived based on the symmetrical rule sampling method. In this embodiment, please refer to Figure 4. Figure 4 is a partial schematic diagram of an embodiment of the duty cycle wavetable provided by the present invention. , set the initial value of the autoload register of the microcontroller timer to 4000 (that is, when the value in the wave table is 4000, the corresponding duty cycle at this time is 1). However, in order to leave a margin for upward and downward adjustment during the initial adjustment, the present invention takes the register values corresponding to the median value and peak value of the duty cycle to be around 2000, and then generates a certain number of register values through the duty cycle expression. Switching device duty cycle wavetable (the number generated in this invention is 400, which can be set according to the accuracy requirements).

Please refer to Figure 5. Figure 5 is a schematic flow chart of an embodiment of step S202 in Figure 2 provided by the present invention. In some embodiments of the present invention, the current standard value is determined according to the phase offset and the duty cycle wave table. include:

S501. Determine the half cycle of the phase voltage;

S502. Determine the wavetable index value according to the half cycle of the phase voltage and the duty cycle wavetable;

S503. Determine the current standard value according to the wavetable index value and phase offset.

In the above embodiment, the state of the phase voltage is divided into positive half cycle and negative half cycle. First set the zero-crossing detection circuit, connect the zero-crossing detection circuit to the I/O interface of the microcontroller, and set the timer interrupt to rising/falling edge Trigger mode, this design can determine whether the phase voltage is in the positive half cycle or the negative half cycle, so that the corresponding value in the duty cycle wave table is input into the PID controller as a reference value, that is, which reference value will be input into the PID for processing, and can be set later The initial value of the phase offset. The difference between the positive half cycle and the negative half cycle of the phase voltage will affect the determined current standard value.

In the present invention, the phase voltage is taken to be in the positive half cycle as an example. The following is the wavetable index value when the single-chip microcomputer detects the falling edge, that is, the AC voltage is about to be in the positive half cycle:

Among them, i _{u_index} , i _{v_index} , and i _{w_index} respectively represent the wavetable index values of different three-phase currents.

In order to realize the phase shift of the AC side current to generate the phase difference between the AC voltage measurement and the current and thereby adjust the rectifier power factor, the present invention adds the phase offset value Phase (initial setting Phase) after the three-phase index value at the zero crossing point. The value is 0, which can be adjusted according to the needs of the power factor), that is, when the AC voltage is about to be in the positive half cycle:

That is, the current standard value is obtained.

Please refer to Figure 6. Figure 6 is a schematic flow chart of an embodiment of step S203 in Figure 2 provided by the present invention. In some embodiments of the present invention, the output voltage is step-adjusted and determined according to the wave table coefficient and the current standard value. Current reference values, including:

S601. Set initial wavetable coefficients;

S602. If the initial wavetable coefficient does not meet the preset conditions, adjust the initial wavetable coefficient until the output voltage meets the preset voltage reference value, and obtain the target wavetable coefficient;

S603. Multiply the target wavetable coefficient and the current standard value to obtain the current reference value.

In the above embodiment, the present invention uses the introduced wave table coefficient M to multiply the current reference value, that is, multiplying the current standard value by M to realize step adjustment of the voltage and obtain the current reference value. The specific method is: collect the DC side output voltage of the three-phase four-wire PWM rectifier through the direct memory access method of the ADC, and compare the result with the reference value after digital filtering. If the actual voltage is greater than the reference value, the value of M will be reduced. On the contrary, the value of M will be increased. After continuous step adjustment, the final output voltage can be stabilized near the reference value, that is, ΔU approaches 0.

Please refer to Figure 7. Figure 7 is a schematic flow chart of an embodiment of controlling a three-phase four-wire PWM rectifier provided by the present invention. In some embodiments of the present invention, the initial offset and current difference are input to the PID. The controller calculates the duty cycle to control the three-phase four-wire PWM rectifier, including:

S701. Determine multiple consecutive current offset values based on the initial offset amount and current difference value;

S702. Based on the discrete expression of the PID controller, calculate the duty cycle based on multiple current bias values;

S703. Adjust the AC side inductor current and output voltage of the three-phase four-wire PWM rectifier according to the duty cycle.

In some embodiments of the present invention, the discrete expression of the PID controller is as follows:

Δu(k)＝K _p [e _r (k)-e _r (k-1)]+K _i e _r (k)+K _d [e _r (k)-2e _r (k-1)+e _r (k-2)];

Among them, Δu(k) represents the duty cycle of the controller output, K _p , K _i , K _d represent the proportional, integral and differential gain coefficients respectively, e _r (k), e _r (k-1), e _r (k-2) respectively represent the k-th current offset value, the k-1-th current offset value and the k-2-th current offset value.

In the above embodiment, in order to achieve DC side capacitor voltage balance control, the present invention adds a bias DC_Bias to the input end of the PID controller, that is, the input of the PID controller is:

e _r (k)=I _ADC (k)-I _ref (k)+DC_Bias;

Among them, I _ADC (k) represents the k-th AC side inductor current of the three-phase four-wire PWM rectifier currently collected through the ADC, and I _ref (k) represents the k-th current reference value output by the voltage outer loop.

The PID controller performs adjustment control according to the register, and the output is the increment of the duty cycle that needs to be set this time to realize the actual AC side inductor current following the current reference value calculated by the voltage outer loop, thereby achieving sinusoidalization of the input current.

The microcontroller detects the total DC side voltage and the lower tube capacitor voltage of the three-phase four-wire PWM rectifier. If the total voltage is greater than twice the lower tube voltage, the bias amount DC_Bias is increased, otherwise the bias amount DC_Bias is reduced. Since the DC component of the neutral line current is equal to the sum of the DC components of the three-phase currents, and is also equal to the difference between the DC components of the upper and lower group capacitor currents, the upper and lower tube capacitances can be adjusted by simultaneously increasing or decreasing the DC components of the three-phase four-wire PWM rectifier. The difference between the voltages enables control of the three-phase four-wire PWM rectifier. It should be noted that the PID controller in this embodiment is an incremental discrete PID controller.

In order to better implement the three-phase four-wire PWM rectifier bridge control method in the embodiment of the present invention, based on the three-phase four-wire PWM rectifier bridge control method, correspondingly, please refer to Figure 8, which shows the three-phase four-wire PWM rectifier bridge control method provided by the present invention. A schematic structural diagram of an embodiment of a three-phase four-wire PWM rectifier bridge control device. This embodiment of the present invention provides a three-phase four-wire PWM rectifier bridge control device 800, which includes:

The voltage loop module 810 is used to determine the current reference value based on the output voltage of the three-phase four-wire PWM rectifier and the voltage outer loop parameters;

The current loop module 820 is used to determine the current difference based on the current inner loop, based on the AC side inductor current and the current reference value of the three-phase four-wire PWM rectifier;

The control module 830 is used to set the initial offset, and input the initial offset and current difference to the PID controller to calculate the duty cycle to control the three-phase four-wire PWM rectifier.

It should be noted here that the device 800 provided in the above embodiments can implement the technical solutions described in the above method embodiments. For the specific implementation principles of each of the above modules or units, please refer to the corresponding content in the above method embodiments, which will not be repeated here. Repeat.

Please refer to FIG. 9 , which is a schematic structural diagram of a three-phase four-wire PWM rectifier control device provided by an embodiment of the present invention. Based on the above three-phase four-wire PWM rectifier bridge control method, the present invention also provides a three-phase four-wire PWM rectifier bridge control device. The three-phase four-wire PWM rectifier bridge control device can be a mobile terminal, a desktop computer, a notebook , handheld computers and servers and other computing equipment. The three-phase four-wire PWM rectifier bridge control device includes a processor 910 , a memory 920 and a display 930 . FIG. 9 only shows some components of the three-phase four-wire PWM rectifier control device, but it should be understood that implementation of all the components shown is not required, and more or less components may be implemented instead.

In some embodiments, the memory 920 may be an internal storage unit of the three-phase four-wire PWM rectifier bridge control device, such as a hard disk or memory of the three-phase four-wire PWM rectifier bridge control device. In other embodiments, the memory 920 may also be an external storage device of the three-phase four-wire PWM rectifier bridge control device, such as a plug-in hard disk or a smart media card equipped on the three-phase four-wire PWM rectifier bridge control device. , SMC), Secure Digital (SD) card, Flash Card, etc. Further, the memory 920 may also include both an internal storage unit of the three-phase four-wire PWM rectifier bridge control device and an external storage device. The memory 920 is used to store application software and various data installed on the three-phase four-wire PWM rectifier bridge control device, such as program codes for installing the three-phase four-wire PWM rectifier bridge control device. The memory 920 can also be used to temporarily store data that has been output or is to be output. In one embodiment, a three-phase four-wire PWM rectifier bridge control program 940 is stored in the memory 920. The three-phase four-wire PWM rectifier bridge control program 940 can be executed by the processor 910, thereby realizing the three-phase four-wire PWM rectifier bridge control program 940 in each embodiment of the present application. Four-wire PWM rectifier bridge control method.

In some embodiments, the processor 910 may be a central processing unit (CPU), a microprocessor or other data processing chip, used to run the program code stored in the memory 920 or process data, such as executing a three-phase four-phase Line PWM rectifier bridge control method, etc.

In some embodiments, the display 930 may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, an OLED (Organic Light-Emitting Diode, organic light-emitting diode) touch device, etc. The display 930 is used to display information on the three-phase four-wire PWM rectifier bridge control device and to display a visual user interface. The components 910-930 of the three-phase four-wire PWM rectifier bridge control device communicate with each other through the system bus.

In one embodiment, when the processor 910 executes the three-phase four-wire PWM rectifier bridge control program 940 in the memory 920, the above steps in the three-phase four-wire PWM rectifier bridge control method are implemented.

This embodiment also provides a computer-readable storage medium on which a three-phase four-wire PWM rectifier bridge control program is stored. When the three-phase four-wire PWM rectifier bridge control program is executed by the processor, the following steps are implemented:

Determine the current reference value based on the output voltage of the three-phase four-wire PWM rectifier and the voltage outer loop parameters;

Based on the current inner loop, the current difference is determined based on the AC side inductor current and current reference value of the three-phase four-wire PWM rectifier;

Set the initial offset, and input the initial offset and current difference to the PID controller to calculate the duty cycle to control the three-phase four-wire PWM rectifier.

In summary, this embodiment provides a three-phase four-wire PWM rectifier control method, device, equipment and storage medium. The method includes: determining the current reference value according to the output voltage of the three-phase four-wire PWM rectifier and the voltage outer loop parameters. ; Based on the current inner loop, determine the current difference according to the AC side inductor current of the three-phase four-wire PWM rectifier and the current reference value; set the initial offset, and compare the initial offset and the current difference Input to the PID controller to calculate the duty cycle to control the three-phase four-wire PWM rectifier. This invention first determines the current reference value by controlling the designed voltage outer loop, and then determines the current difference based on the designed current inner loop based on the current reference value and the AC side inductor current, and then determines the current offset by setting the initial offset. value, successively through the double-loop closed control of the voltage outer loop and the current inner loop, and finally through only one PID controller, the AC side inductor current and output voltage of the three-phase four-wire PWM rectifier can be adjusted, reducing the need for a PID controller. Quantity makes the control algorithm simpler and the analysis process more concise, so it can be better put into engineering practice.

The above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person familiar with the technical field can easily think of changes or modifications within the technical scope disclosed in the present invention. All substitutions are within the scope of the present invention.

Claims (10)

1. A three-phase four-wire PWM rectifier control method, characterized by including: Determine the current reference value based on the output voltage of the three-phase four-wire PWM rectifier and the voltage outer loop parameters; Based on the current inner loop, the current difference is determined based on the AC side inductor current of the three-phase four-wire PWM rectifier and the current reference value; An initial offset is set, and the initial offset and the current difference are input to the PID controller to calculate the duty cycle and control the three-phase four-wire PWM rectifier. 2. The three-phase four-wire PWM rectifier control method according to claim 1, characterized in that, based on the voltage outer loop, the current reference value is determined according to the output voltage of the three-phase four-wire PWM rectifier, including: Generate a duty cycle wavetable based on the duty cycle expression and the initial value of the autoload register of the microcontroller timer; Set the phase offset, and determine the current standard value based on the phase offset and the duty cycle wave table; The output voltage is step-adjusted according to the wavetable coefficient and the current standard value to determine the current reference value. 3. The three-phase four-wire PWM rectifier control method according to claim 2, characterized in that the duty cycle wave table is generated according to the duty cycle expression and the initial value of the automatic loading register of the microcontroller timer, including: The duty cycle expression is: Among them, D is the duty cycle value, N is the number of values in the wave table, k is a specific value from 0 to N, and m is the modulation degree; Determine the wavetable median value based on the initial value of the auto-load register of the microcontroller timer; A duty cycle wavetable is generated according to the wavetable median value and the duty cycle expression. 4. The three-phase four-wire PWM rectifier control method according to claim 2, wherein determining the current standard value according to the phase offset and the duty cycle wave table includes: Determine the half cycle of the phase voltage; Determine the wavetable index value according to the half cycle where the phase voltage is located and the duty cycle wavetable; The current standard value is determined according to the wavetable index value and the phase offset. 5. The three-phase four-wire PWM rectifier control method according to claim 2, wherein the step adjustment of the output voltage to determine the current reference value according to the wave table coefficient and the current standard value includes: Set initial wavetable coefficients; If the initial wavetable coefficient does not meet the preset condition, adjust the initial wavetable coefficient until the output voltage meets the preset voltage reference value to obtain the target wavetable coefficient; Multiply the target wavetable coefficient and the current standard value to obtain a current reference value. 6. The three-phase four-wire PWM rectifier control method according to claim 1, wherein the initial offset and the current difference are input to the PID controller to calculate the duty cycle of the three-phase four-wire PWM rectifier. Phase four-wire PWM rectifier controls include: Determine multiple consecutive current bias values according to the initial bias amount and the current difference value; Calculate a duty cycle based on the plurality of current bias values based on the discrete expression of the PID controller; The AC side inductor current and output voltage of the three-phase four-wire PWM rectifier are adjusted according to the duty cycle. 7. The three-phase four-wire PWM rectifier control method according to claim 6, characterized in that the discrete expression of the PID controller is as follows: Δu(k)＝K _p [e _r (k)-e _r (k-1)]+K _i e _r (k)+K _d [e _r (k)-2e _r (k-1)+e _r (k-2)]; Among them, Δu(k) represents the duty cycle of the controller output, K _p , K _i , K _d represent the proportional, integral and differential gain coefficients respectively, e _r (k), e _r (k-1), e _r (k-2) respectively represent the k-th current offset value, the k-1-th current offset value and the k-2-th current offset value. 8. A three-phase four-wire PWM rectifier control device, characterized by including: The voltage loop module is used to determine the current reference value based on the output voltage of the three-phase four-wire PWM rectifier and the voltage outer loop parameters; The current loop module is used to determine the current difference based on the current inner loop based on the AC side inductor current of the three-phase four-wire PWM rectifier and the current reference value; A control module, configured to set an initial offset, and input the initial offset and the current difference into a PID controller to calculate a duty cycle to control the three-phase four-wire PWM rectifier. 9. A three-phase four-wire PWM rectifier control device, characterized by including a memory and a processor, wherein, The memory is used to store programs; The processor is coupled to the memory and is used to execute the program stored in the memory to implement the steps in the three-phase four-wire PWM rectifier control method in any one of claims 1 to 7. 10. A computer-readable storage medium, characterized in that it is used to store computer-readable programs or instructions. When the programs or instructions are executed by a processor, they can realize any one of the above claims 1 to 7. Describe the steps in the three-phase four-wire PWM rectifier control method.