Three-phase full-bridge PFC four-quadrant operation control method

Abstract

The invention discloses a three-phase full-bridge PFC (Power Factor Correction) four-quadrant operation control method, which comprises the following steps: S1, establishing a three-phase full-bridge PFC topological structure, and inputting three-phase voltage to the three-phase full-bridge PFC topological structure to obtain a plurality of electric energy parameters; s2, analyzing the three-phase full-bridge PFC topological structure to obtain a three-phase PFC mathematical model of the electric energy parameters; s3, performing three-phase PFC control on the three-phase voltage according to the three-phase PFC mathematical model to obtain a three-phase voltage expression; s4, performing coordinate transformation on the three-phase voltage expression to obtain a four-quadrant operation control algorithm of the three-phase voltage; and S5, controlling the three-phase voltage according to a four-quadrant operation control algorithm of the three-phase voltage. According to the three-phase full-bridge PFC four-quadrant operation control method, when a load provides a three-phase voltage through a power grid, four-quadrant operation control can be performed on the three-phase voltage through the algorithm, so that the phase of the three-phase voltage is quickly converged, the input current of the load can be enabled to follow the input voltage, energy is directly absorbed from the power grid, and the power supply efficiency is improved. And meanwhile, energy is fed back to the power grid.

Description

Technical Field

[0001] The present invention belongs to the field of three-phase power supply control, and particularly relates to a three-phase full-bridge PFC four-quadrant operation control method. Background Art

[0002] In recent years, with the comprehensive development of the electrical engineering technology field and the full popularization of new energy vehicles, people's demands for high voltage, high power, and high frequency of power electronic devices have become increasingly strong. When power electronic devices are connected to the power grid, a large amount of harmonics and power grid pollution will be generated. To solve the power grid harmonic problem, relevant researchers have proposed a three-phase full-bridge PFC circuit topology and conducted a large amount of research work on it, which can achieve sinusoidal input grid current and a unity power factor of 1. However, there is little research on the control strategy for the two-way energy flow and four-quadrant operation of the three-phase full-bridge PFC.

[0003] The patent with the patent number "ZL202310871095.3" discloses a three-phase PFC circuit cascaded dual-winding motor control circuit and control method, which can control the power transmission of the three-phase PFC circuit cascaded dual-winding motor control circuit in the on-vehicle charger mode. However, this power transmission can only operate in the positive resistance mode and cannot feed back energy. Summary of the Invention

[0004] The purpose of the present invention is to provide a three-phase full-bridge PFC four-quadrant operation control method, which directly extracts phase information from the three-phase voltage, enables the current phase to follow the voltage, and the power transmission can operate in both positive resistance and negative resistance modes.

[0005] To achieve the above invention purpose, the technical solution adopted by the present invention is as follows:

[0006] A three-phase full-bridge PFC four-quadrant operation control method includes the following steps:

[0007] Step S1. Establish a three-phase full-bridge PFC topology structure, and obtain multiple power parameters from the input three-phase voltage;

[0008] Step S2. Analyze the three-phase full-bridge PFC topology structure to obtain a three-phase PFC mathematical model of the power parameters;

[0009] Step S3. According to the three-phase PFC mathematical model, perform three-phase PFC control on the three-phase voltage to obtain a three-phase voltage expression;

[0010] Step S4. Perform coordinate transformation on the three-phase voltage expression to obtain a four-quadrant operation control algorithm for the three-phase voltage;

[0011] Step S5. Control it according to the four-quadrant operation control algorithm of the three-phase voltage.

[0012] A three-phase full-bridge PFC four-quadrant operation control method of the present invention can directly obtain phase information from the input three-phase voltage through three-phase PFC control of the three-phase voltage, and then obtain the three-phase voltage expression. Through coordinate transformation, an algorithm for four-quadrant operation control of the three-phase voltage is finally obtained. When a load provides three-phase voltage through the power grid, the four-quadrant operation control of the three-phase voltage can be performed through this algorithm, so that the phase of the three-phase voltage converges rapidly, and then the input current of the load can follow the input voltage, directly absorbing energy from the power grid and at the same time feeding back energy to the power grid.

[0013] Preferably, the three-phase full-bridge PFC topology includes a first resistor R a , a second resistor R b , a third resistor R c , a first inductor L a , a second inductor L b , a third inductor L c , a first switching tube Q 1 , a second switching tube Q 2 , a third switching tube Q 3 , a fourth switching tube Q 4 , a fifth switching tube Q 5 , a sixth switching tube Q 6 , a capacitor C, an output voltage u c , a load R load .

[0014] Preferably, the step S1 includes: inputting three-phase voltage into the three-phase full-bridge PFC topology through a three-phase power supply to obtain the voltages e a , e b , e c of the three-phase power supply and their voltages u a , u b , u c relative to the point 0, and obtaining the currents i a , i b , i c of the three-phase power supply, and at the same time obtaining the branch current i load and the trunk current i L dc of the load R.

[0015] Preferably, in the step S2, the three-phase PFC mathematical model of the electrical energy parameters is

[0016]

[0017] and

[0018]

[0019] ; where The induced voltages of the first inductor L a , the second inductor L b , and the third inductor L c respectively; where Ri a , Ri b , and Ri c are the voltages across the first resistor R a , the second resistor R b , and the third resistor R c respectively; is the voltage across the capacitor C.

[0020] Preferably, the three-phase PFC control includes voltage outer-loop control, current inner-loop control, and voltage-current phase control.

[0021] Preferably, the step S3 includes:

[0022] Step S3.1. Perform voltage outer-loop control on the three-phase voltage to obtain the three-phase current in the ABC stationary coordinate system;

[0023] Step S3.2. Convert the three-phase current in the ABC stationary coordinate system into the three-phase current in the dq rotating coordinate system;

[0024] Step S3.3. Perform current inner-loop control on the three-phase current in the dq rotating coordinate system to obtain the inner-loop control current;

[0025] Step S3.4. Extract the phase information from the three-phase voltage, and perform voltage-current phase control on the inner-loop control current according to the phase information to obtain the three-phase voltage expression.

[0026] Preferably, in the step S3.4, the phase information includes the phase angle ω of the three-phase voltage; the three-phase voltage expression of the three-phase voltage U is

[0027]

[0028] Preferably, the step S4 includes:

[0029] Step S4.1. Perform coordinate transformation on the three-phase voltage expression of the three-phase voltage U to obtain two expressions of the voltages u a , u b as

[0030]

[0031] and

[0032]

[0033] Preferably, the step S4 further includes:

[0034] Step S4.2. Analyze voltage u a and u b 's two expressions to obtain the four - quadrant operation control algorithm for three - phase voltage as

[0035]

[0036] and

[0037]

[0038] Preferably, the four - quadrant operation control method for three - phase full - bridge PFC further includes:

[0039] Step S6. Control the three - phase voltage according to the four - quadrant operation control algorithm of the three - phase voltage, and chop the controlled three - phase voltage to obtain the corresponding waveform diagram.

[0040] Beneficial effects:

[0041] A four - quadrant operation control method for three - phase full - bridge PFC of the present invention can directly obtain phase information from the input three - phase voltage through three - phase PFC control of the three - phase voltage, and then obtain the three - phase voltage expression. Through coordinate transformation, an algorithm for four - quadrant operation control of the three - phase voltage can be finally obtained; when a load provides three - phase voltage through the power grid, the four - quadrant operation control of the three - phase voltage can be performed through this algorithm, enabling the phase of the three - phase voltage to converge quickly. Furthermore, it can make the input current of the load follow the input voltage, directly absorb energy from the power grid, and at the same time feed energy back to the power grid. Description of the drawings

[0042] Figure 1 Shown is the overall flowchart of a four - quadrant operation control method for three - phase full - bridge PFC in Embodiment 1;

[0043] Figure 2 Shown is the sub - flowchart of a four - quadrant operation control method for three - phase full - bridge PFC in Embodiment 1;

[0044] Figure 3 Shown is the three - phase full - bridge PFC topology structure in Embodiment 1;

[0045] Figure 4 Shown is the simplified model of the three - phase full - bridge PFC topology structure in Embodiment 1;

[0046] Figure 5 Shown is the first vector relationship diagram among vectors e, v, and i in Embodiment 1;

[0047] Figure 6 Shown is the second vector relationship diagram among vectors e, v, and i in Embodiment 1;

[0048] Figure 7The figure shows the third vector relationship diagram among vectors e, v, and i in the first embodiment;

[0049] Figure 8 The figure shows the fourth vector relationship diagram among vectors e, v, and i in the first embodiment;

[0050] Figure 9 The figure shows the fifth vector relationship diagram among vectors e, v, and i in the first embodiment;

[0051] Figure 10 The figure shows the sixth vector relationship diagram among vectors e, v, and i in the first embodiment;

[0052] Figure 11 The figure shows the voltage outer loop control block diagram in the first embodiment;

[0053] Figure 12 The figure shows the current inner loop control block diagram in the first embodiment;

[0054] Figure 13 The figure shows the waveform comparison diagram of the phase information in the first embodiment and the phase information of the traditional phase-locked loop;

[0055] Figure 14 The figure shows the waveform comparison diagram of the current varying with voltage in the first embodiment and the current varying with voltage of the traditional phase-locked loop;

[0056] Figure 15 The figure shows the three-phase current waveform diagram without PFC in the second embodiment;

[0057] Figure 16 The figure shows the waveform diagram when the three-phase PFC in the second embodiment is operating under three-phase unbalanced conditions;

[0058] Figure 17 The figure shows the waveform diagram when the three-phase PFC in the second embodiment is operating under a loaded state;

[0059] Figure 18 The figure shows the waveform diagram when the three-phase PFC in the second embodiment is operating in a negative resistance mode;

[0060] Figure 19 The figure shows the voltage-current following waveform diagram of the three-phase PFC in the second embodiment;

[0061] Figure 20 The figure shows the 700V DC bus waveform diagram of the three-phase PFC in the second embodiment. Specific implementation manners

[0062] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will describe the specific embodiments of the present invention with reference to the accompanying drawings. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings and other embodiments can be obtained.

[0063] The following will introduce the technical solutions of the present invention in detail with specific embodiments.

[0064] Embodiment 1

[0065] As Figures 1 - 13 shown, a three-phase full-bridge PFC four-quadrant operation control method in this embodiment includes the following steps:

[0066] Step S1. Establish a three-phase full-bridge PFC topology structure, and obtain multiple power parameters for its input three-phase voltage;

[0067] Step S2. Analyze the three-phase full-bridge PFC topology structure to obtain a three-phase PFC mathematical model of the power parameters;

[0068] Step S3. According to the three-phase PFC mathematical model, perform three-phase PFC control on the three-phase voltage to obtain a three-phase voltage expression;

[0069] Step S4. Perform coordinate transformation on the three-phase voltage expression to obtain a four-quadrant operation control algorithm for the three-phase voltage;

[0070] Step S5. Control it according to the four-quadrant operation control algorithm of the three-phase voltage.

[0071] A three-phase full-bridge PFC four-quadrant operation control method in this embodiment can directly obtain phase information from the input three-phase voltage through three-phase PFC control on the three-phase voltage, and then obtain a three-phase voltage expression. Through coordinate transformation, an algorithm for four-quadrant operation control of the three-phase voltage can be finally obtained; when there is a load providing three-phase voltage through the power grid, the three-phase voltage can be controlled for four-quadrant operation through this algorithm, so that the phase of the three-phase voltage converges quickly, and then the input current of the load can follow the input voltage, directly absorbing energy from the power grid and at the same time feeding back energy to the power grid.

[0072] Preferably, the three-phase full-bridge PFC topology structure includes a first resistor R a , a second resistor R b , a third resistor R c , a first inductor L a , a second inductor L b , a third inductor L c , a first switching tube Q 1 , a second switching tube Q2 and the third switching transistor Q 3 and the fourth switching transistor Q 4 and the fifth switching transistor Q 5 and the sixth switching transistor Q 6 capacitor C, output voltage u c load R load .

[0073] Preferably, step S1 includes: inputting three-phase voltages to a three-phase full-bridge PFC topology through a three-phase power supply to obtain the voltages e a , e b , e c of the three-phase power supply and their voltages u a , u b , u c with respect to point 0, and obtaining the currents i a , i b , i c of the three-phase power supply. At the same time, obtain the branch current i load and the main circuit current i L of the load R dc .

[0074] Preferably, in step S2, the three-phase PFC mathematical model for obtaining power parameters is

[0075]

[0076] and

[0077]

[0078] ; where are the induced voltages of the first inductor L a , the second inductor L b , and the third inductor L c respectively; where Ri a , Ri b , Ri c are the voltages across the first resistor R a , the second resistor R b , and the third resistor R c respectively; is the voltage across the capacitor C.

[0079] Preferably, the three-phase PFC control includes voltage outer loop control, current inner loop control, and voltage-current phase control.

[0080] Preferably, step S3 includes:

[0081] Step S3.1. Perform voltage outer loop control on the three-phase voltages to obtain the three-phase currents in the ABC stationary coordinate system;

[0082] Step S3.2. Convert the three-phase current in the ABC stationary coordinate system into the three-phase current in the dq rotating coordinate system;

[0083] Step S3.3. Perform current inner-loop control on the three-phase current in the dq rotating coordinate system to obtain the inner-loop control current;

[0084] Step S3.4. Extract the phase information from the three-phase voltage, and perform voltage-current phase control on the inner-loop control current according to the phase information to obtain the three-phase voltage expression.

[0085] Preferably, in Step S3.4, the phase information includes the phase angle ω of the three-phase voltage; the three-phase voltage expression of the three-phase voltage U is

[0086]

[0087] Preferably, Step S4 includes:

[0088] Step S4.1. Perform coordinate transformation on the three-phase voltage expression of the three-phase voltage U to obtain the voltages u a 、u b The two expressions are

[0089]

[0090] and

[0091]

[0092] Preferably, Step S4 further includes:

[0093] Step S4.2. Analyze the two expressions of the voltages u a 、u b to obtain the four-quadrant operation control algorithm of the three-phase voltage as

[0094]

[0095] and

[0096]

[0097] Preferably, the three-phase full-bridge PFC four-quadrant operation control method further includes:

[0098] Step S6. Control the three-phase voltage according to the four-quadrant operation control algorithm of the three-phase voltage, and chop the controlled three-phase voltage to obtain the corresponding waveform diagram.

[0099] Specifically, as Figure 3 shown is the three-phase full-bridge PFC topology structure of this embodiment, where, e a 、e b 、ec is the three-phase power supply voltage; u a , u b , u c are the voltages of the three phases relative to point 0, and i a , i b , i c are the three-phase currents respectively, and R a , R b , R c are the resistances of the three-phase line impedances respectively, and L a , L b , L c are the line inductances respectively, and Q 1 , Q 2 , Q 3 , Q 4 , Q 5 , Q 6 are the switching tubes respectively, C is the output bus capacitor, and u c is the bus output voltage, and R load is the simulated resistive load. The three-phase power supply in this embodiment is provided by a power grid composed of three-phase alternating current, and R load acts as a load that is connected to the power grid and is provided with three-phase voltages.

[0100] Specifically, as Figure 4 shown is the simplified model of the three-phase full-bridge PFC topology in this embodiment. The source voltage e, equivalent voltage v, equivalent inductance L, and equivalent current i in the figure satisfy e = v + jωLi.

[0101] Specifically, as Figures 5 - 10 shown is the vector relationship diagram among vectors e, v, and i, where:

[0102] Figure 5 shown is the inductive operation diagram of the three-phase voltages in the three-phase full-bridge PFC topology. At this time, the three-phase PFC absorbs inductive reactive power from the power grid;

[0103] Figure 6 shown is the resistive-inductive operation diagram of the three-phase voltages in the three-phase full-bridge PFC topology. At this time, the three-phase PFC absorbs inductive reactive power and active power from the power grid;

[0104] Figure 7 shown is the resistive operation diagram of the three-phase voltages in the three-phase full-bridge PFC topology. At this time, the three-phase PFC absorbs active power from the power grid;

[0105] Figure 8 shown is the capacitive operation diagram of the three-phase voltages in the three-phase full-bridge PFC topology. At this time, the three-phase PFC absorbs capacitive reactive power from the power grid;

[0106] Figure 9The figure shows the resistive-capacitive operation diagram of three-phase voltage in a three-phase full-bridge PFC topology. At this time, the three-phase PFC absorbs capacitive reactive power and negative active power from the power grid;

[0107] Figure 10 The figure shows the negative-resistance operation diagram of three-phase voltage in a three-phase full-bridge PFC topology. At this time, the three-phase PFC absorbs negative active power from the power grid;

[0108] Specifically, Figure 11 The figure shows the voltage outer-loop control block diagram of this embodiment. By controlling the voltage outer loop of the three-phase voltage, the three-phase current in the ABC stationary coordinate system is obtained.

[0109] Specifically, the three-phase current is transformed from the ABC stationary coordinate system to the dq rotating coordinate system, and then the current inner-loop control is performed. In this embodiment, i d represents the active power, and i q represents the reactive power. At this time, i q = 0. Therefore, the current inner-loop control block diagram of this embodiment is as shown in Figure 12 the figure.

[0110] Specifically, in this embodiment, when controlling the voltage-current phase, instead of choosing a phase-locked loop, the phase information is extracted from the three-phase voltage. By directly obtaining the phase information in this embodiment, as shown in the waveform diagram compared with the traditional phase-locked loop Figure 13 the figure, through this method, the four-quadrant operation control algorithm of the three-phase voltage is finally obtained. The control of the three-phase voltage can make the voltage-current phase information converge quickly. While using the traditional phase-locked loop, the phase gradually converges in two power-frequency cycles. The comparison diagram of the convergence speed reflected in the voltage-current waveform is as shown in Figure 14 the figure.

[0111] Embodiment 2

[0112] As another implementation manner of Embodiment 1, this embodiment controls the voltage across the load R Figure 1 to 800V, so that the PFC output bus voltage is 700V (as shown in load ), and adopts the control strategy of Iq = 0. Figure 20 )

[0113] Furthermore, every 0.5s, the three-phase PFC is respectively switched for three-phase unbalance, load addition and subtraction, and four-quadrant operation, and the simulation time is set to 1s. Among them, between 0.1s - 0.2s, the three-phase PFC has single-phase grounding and is in three-phase unbalanced operation (as shown in Figure 16 ), between 0.25 - 0.4s, it is in the loaded state operation (as shown in Figure 17 ), and at 0.5s, it is in the negative-resistance operation mode (such as 18), and the voltage-current phase difference is 180°.

[0114] Specifically, for the three-phase voltage in this embodiment, when the PFC is not turned on (such as Figure 15 ), the input current will be distorted; when the three phases are unbalanced, the input current is not disordered and has a high sinusoidal degree; when switching the load up and down, the input current is overly stable; when operating in a negative resistance mode, the phase difference between the voltage and current is 180°, indicating bidirectional energy flow, meeting the three-phase PFC four-quadrant operation criterion, and the voltage and current follow waveform diagrams of the three-phase PFC as shown in Figure 19 .

[0115] Furthermore, the three-phase PFC four-quadrant operation in this embodiment can operate in a positive resistance mode to absorb grid energy or in a negative resistance mode to feed back grid energy.

[0116] The above has elaborated in detail on the embodiments of a three-phase full-bridge PFC four-quadrant operation control method provided by the present invention. Specific examples are used herein to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the core idea of the present invention. It should be pointed out that for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and modifications can still be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A three-phase full-bridge PFC four-quadrant operation control method, characterized in that: The following steps are involved: Step S1. Establish a three-phase full-bridge PFC topology structure, and obtain multiple power parameters from its input three-phase voltage; Step S2. Analyze the three-phase full-bridge PFC topology structure to obtain a three-phase PFC mathematical model of power parameters; Step S3. Perform three-phase PFC control on the three-phase voltage according to the three-phase PFC mathematical model to obtain a three-phase voltage expression; Step S4. Perform coordinate transformation on the three-phase voltage expression to obtain a four-quadrant operation control algorithm for the three-phase voltage; Step S5: Control the three-phase voltage according to the four-quadrant operation control algorithm.

2. The three-phase full-bridge PFC four-quadrant operation control method according to claim 1, characterized in that: The three-phase full-bridge PFC topology structure includes a first resistor R a , the second resistor R b , the third resistor R c , the first inductor L a , the second inductor L b , the third inductor L c , the first switch tube Q1, the second switch tube Q2, the third switch tube Q3, the fourth switch tube Q4, the fifth switch tube Q5, the sixth switch tube Q6, the capacitor C, the output voltage u c 、Load R load .

3. The three-phase full-bridge PFC four-quadrant operation control method according to claim 2, characterized in that: The step S1 includes: inputting a three-phase voltage to the three-phase full-bridge PFC topology structure through a three-phase power supply, obtaining a voltage e of the three-phase power supply a 、e b 、e c and their voltage u relative to the 0 point a 、u b 、u c , and obtain the current i of the three-phase power supply a 、i b 、i c , while obtaining the load R load The branch current i L and the main circuit current i dc .

4. The three-phase full-bridge PFC four-quadrant operation control method according to claim 3 is characterized in that: In step S2, the three-phase PFC mathematical model of the electric energy parameters is obtained as follows: and ； in The first inductor L a , the second inductor L b , the third inductor L c The induced voltage Ri a 、Ri b 、Ri c The first resistor R a , the second resistor R b , the third resistor R c The voltage across the two ends of is the voltage across capacitor C.

5. The three-phase full-bridge PFC four-quadrant operation control method according to claim 4, characterized in that: The three-phase PFC control includes voltage outer loop control, current inner loop control, and voltage and current phase control.

6. The three-phase full-bridge PFC four-quadrant operation control method according to claim 5, characterized in that: The step S3 comprises: Step S3.

1. Perform voltage outer loop control on the three-phase voltage to obtain the three-phase current of the ABC stationary coordinate system; Step S3.

2. Convert the three-phase current of the ABC stationary coordinate system into the three-phase current of the dq rotating coordinate system; Step S3.

3. Perform current inner loop control on the three-phase current of the dq rotating coordinate system to obtain the inner loop control current; Step S3.

4. Extract phase information from the three-phase voltage, perform voltage and current phase control on the inner loop control current according to the phase information, and obtain a three-phase voltage expression.

7. The three-phase full-bridge PFC four-quadrant operation control method according to claim 6, characterized in that: In step S3.4, the phase information includes the phase angle ω of the three-phase voltage; the three-phase voltage expression of the three-phase voltage U is:

8. The three-phase full-bridge PFC four-quadrant operation control method according to claim 7, characterized in that: The step S4 comprises: Step S4.

1. Perform coordinate transformation on the three-phase voltage expression of the three-phase voltage U to obtain the voltage u a 、u b The two expressions of and 9. The three-phase full-bridge PFC four-quadrant operation control method according to claim 8, characterized in that: The step S4 further comprises: Step S4.

2. Analyze the voltage u a 、u b The two expressions of the four-quadrant operation control algorithm of the three-phase voltage are obtained as follows: and 10. The three-phase full-bridge PFC four-quadrant operation control method according to any one of claims 1 to 9, characterized in that: The three-phase full-bridge PFC four-quadrant operation control method also includes: Step S6: Control the three-phase voltage according to the four-quadrant operation control algorithm of the three-phase voltage, and chop the controlled three-phase voltage to obtain a corresponding waveform diagram.

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