Method and system for controlling a rectifier for driving a siC device air conditioner compressor

Abstract

The application belongs to the technical field of power electronics, and relates to a SiC device air conditioner compressor drive rectifier control method and system, which divides the entire fundamental wave cycle into a zero-crossing point interval and a non-zero-crossing point interval, adopts different control methods in different intervals, and improves the efficiency and harmonic performance of the SiC device air conditioner compressor drive rectifier by using the advantages of different control methods; in the non-zero-crossing point interval, the SiC MOSFET itself anti-parallel diode and the additionally added SiC Schottky diode work together, the SiC MOSFET does not work, and the parallel current path can reduce on-state loss and improve the rectifier efficiency; in the zero-crossing point interval, the SiC MOSFET participates in the work, can cope with the non-unit power factor operation condition, can reduce current distortion, and can reduce harmonics.

Description

Technical Field

[0001] This application belongs to the field of power electronics technology and relates to air conditioner rectifier control technology. Specifically, it relates to a control method and system for a SiC device air conditioner compressor driven rectifier. Background Technology

[0002] Traditional fixed-frequency air conditioners operate with compressors running at a fixed speed. When the indoor temperature drops to a set threshold, the compressor stops; when the indoor temperature rises above the threshold, the compressor restarts, resulting in noticeable start-stop fluctuations. Variable-frequency air conditioners, with their precise speed regulation, can quickly stabilize the indoor temperature at the set value, avoiding temperature fluctuations caused by frequent compressor starts and stops, thus optimizing indoor temperature control comfort. Simultaneously, the variable-frequency operation mode of variable-frequency air conditioners avoids the energy consumption caused by repeated compressor starts and stops, resulting in significant energy savings; it also reduces compressor noise during start-stop operations, making it quieter and significantly superior to traditional fixed-frequency air conditioners in overall performance. The core working unit of a variable-frequency air conditioning system is the compressor drive chain. The compressor drive chain first uses a rectifier to convert external AC power into DC power, and then an inverter converts the DC power into AC power with an adjustable frequency, thereby powering the compressor and precisely regulating its speed.

[0003] The efficiency and harmonic performance of the rectifier driving the air conditioner compressor directly determine whether the entire inverter air conditioning system can operate energy-efficiently. On the one hand, the rectifier driving the air conditioner compressor typically uses traditional silicon (Si) insulated-gate bipolar transistors (IGBTs) and diodes. After long-term technological iteration, their performance has approached its theoretical limit. To further improve the rectifier's efficiency and other performance characteristics, metal-oxide-semiconductor field-effect transistors (MOSFETs) and Schottky diodes made of new silicon carbide (SiC) materials can be used, which offer fast switching speeds, low losses, and high voltage withstand capabilities. On the other hand, with the development of new power systems, the requirements for the current quality of grid loads are becoming increasingly stringent, and many grid access standards have also imposed strict limitations on the current quality of inverter air conditioners. Traditional air conditioner compressor-driven rectifiers require a brief low-level time, or dead time, between the complementary on / off power device drive signals to prevent shoot-through / short-circuit faults in the rectifier. However, the added dead time creates a dead-time effect, causing low-frequency current harmonics in the AC current and reducing the quality of the output current. Summary of the Invention

[0004] This application addresses the aforementioned problems in the existing technology by providing a control method and system for a SiC device air conditioner compressor drive rectifier. The method divides the entire fundamental cycle into current zero-crossing intervals and non-zero-crossing intervals, and employs different control methods in different intervals. By utilizing the advantages of different control methods, the efficiency and harmonic performance of the SiC device air conditioner compressor drive rectifier can be improved.

[0005] In a first aspect, this application provides a method for controlling a SiC device-driven rectifier compressor, comprising: Grid voltage angle extraction steps: Based on the grid voltage phase angle θ1, the three-phase grid voltage is transformed into the dq-axis grid voltage, and the grid voltage phase angle θ1 is updated based on the q-axis grid voltage; Current command generation steps: For the DC side reference voltage... With the actual DC side voltage u dc The difference is used to obtain the d-axis reference current through PI adjustment. ; Current transformation steps: Based on the grid voltage phase angle θ1, the three-phase grid current is transformed into the dq-axis grid current; Control inner loop steps: Based on PI regulation, according to the d-axis reference current. The dq-axis grid current and dq-axis grid voltage generate the dq-axis voltage modulation signal; Three-phase modulated wave generation steps: Based on the actual DC side voltage u dc The phase angle θ1 of the grid voltage is used to generate a three-phase modulated wave signal based on the dq-axis voltage modulation signal; Three-phase modulated wave transformation steps: Combine and transform the three-phase modulated wave signals to generate the initial modulated wave signal. ; Zero-crossing interval modulation steps: The lower DC bus capacitor voltage u... dc2 Subtract the DC bus capacitor voltage u dc1 Obtain the balanced signal n p Balanced signal n p Add initial modulation wave signal Obtain the three-phase initial wave modulation signal; subtract 4T from the i-phase initial wave modulation signal. u f s Obtain the first modulation wave signal of phase i. The initial modulation wave signal of phase i is added with 4T u f s Obtain the i-phase second modulation wave signal Where i = a, b, c, T u f is the driving pulse interval adjustment coefficient. s The switching frequency; based on the three-phase initial wave modulation signal, the three-phase first modulation wave signal, and the three-phase second modulation wave signal. , positive carrier Load wave The magnitude of the three-phase grid current generates the driving signal for the zero-crossing interval; Non-zero-crossing interval modulation steps: based on the three-phase initial modulation signal and the positive carrier. Load wave The magnitude of the three-phase grid current generates a drive signal in the non-zero-crossing range; Drive signal selection steps: Based on the magnitude of the absolute value of the three-phase grid current, the drive signal for the SiC MOSFET power switching device in the air conditioner compressor drive rectifier is selected and generated according to the drive signal in the zero-crossing interval and the drive signal in the non-zero-crossing interval.

[0006] In conjunction with the first aspect, in some embodiments, the method for transforming the three-phase grid voltage into the dq-axis grid voltage in the grid voltage angle extraction step includes: Phase a grid voltage E a Subtract the first set coefficient and multiply by the b-phase grid voltage E b Subtract the first set coefficient and multiply by the c-phase grid voltage E c Then, multiply by the second set coefficient to obtain the α-axis grid voltage E. α ; The third set coefficient is multiplied by the phase b grid voltage E. b Subtract the third set coefficient and multiply by the c-phase grid voltage E c Then, multiply by the second set coefficient to obtain the β-axis grid voltage E. β ; α-axis grid voltage E α The product of cosθ1 and the β-axis grid voltage E β Multiplying by sinθ1, we obtain the d-axis grid voltage e in the two-phase coordinate system. d α-axis grid voltage E α Multiply by -sinθ1 and add the β-axis grid voltage E β Multiplying by cosθ1, we obtain the q-axis grid voltage e in the two-phase coordinate system. q ; Based on the q-axis grid voltage e q Methods for updating the grid voltage phase angle θ1 include: Calculate the grid voltage e along the 0 and q axes. q The difference is used to obtain the first voltage difference; The first voltage difference is passed through a transfer function K. PI1 After the first PI controller with value = 0.25 + 0.35 / s performs PI adjustment, the first intermediate value is obtained; Integrating the difference obtained by subtracting the first intermediate value from 100π, we obtain the grid voltage phase angle θ1.

[0007] In conjunction with the first aspect, in some embodiments, the method for transforming three-phase grid current into dq-axis grid current in the current transformation step includes: Phase a grid current I a Multiply by sinθ1 by the fourth set coefficient, then add the b-phase grid current I. b Multiply by sin(θ1-2π / 3), then add the c-phase grid current I. c Multiplying by sin(θ1+2π / 3) yields the d-axis grid current i. d ; Phase a grid current I a Multiply by cosθ1 by the fourth constant coefficient, then add the b-phase grid current I. b Multiply by cos(θ1-2π / 3), then add the c-phase grid current I. c Multiplying by cos(θ1+2π / 3) yields the q-axis grid current i. q .

[0008] In conjunction with the first aspect, in some embodiments, the method for generating the dq-axis voltage modulation signal in the inner loop control step includes: Reference current for the d-axis Reduce d-axis grid current i d The difference is used to obtain a second intermediate value through PI adjustment, and the q-axis grid current i is reduced from 0. q The difference is adjusted using PI to obtain the third intermediate value; d-axis grid voltage e d Subtract the second intermediate value, then add the q-axis grid current i. q The product of 314L and 314L yields the d-axis voltage modulation signal. Where L is the inductance; q-axis grid voltage e q Subtract the third intermediate value, then subtract the d-axis grid current i. d The product of 314L and 314L yields the q-axis voltage modulation signal. .

[0009] In conjunction with the first aspect, in some embodiments, the method for generating a three-phase modulated wave signal in the three-phase modulated wave generation step includes: d-axis voltage modulation signal Multiply by 2 and divide by the actual DC side voltage u dc The first intermediate voltage modulation signal is obtained. q-axis voltage modulation signal Multiply by 2 and divide by the actual DC side voltage u dc The second intermediate voltage modulation signal is obtained. ; First intermediate voltage modulation signal The product of sinθ1 and the second intermediate voltage modulation signal Multiplying by cosθ1 yields the phase a modulated wave signal. First intermediate voltage modulation signal The product of sin(θ1-2π / 3) and the second intermediate voltage modulation signal Multiplying by cos(θ1-2π / 3) yields the phase b modulated wave signal. First intermediate voltage modulation signal The product of sin(θ1+2π / 3) and the second intermediate voltage modulation signal Multiplying by cos(θ1+2π / 3) yields the c-phase modulated wave signal. .

[0010] In conjunction with the first aspect, in some embodiments, in the three-phase modulation wave transformation step, an initial modulation wave signal is generated. The methods include: Combine the three-phase modulated wave signals into a signal. ; Multiply the signal by the fifth set coefficient to obtain the signal. ; The signal is determined by the judgment module. Is it greater than 0? If signal If the value is greater than 0, then the output of the determination module is a signal. ;if signal If the value is less than 0, the output of the judgment module is 1 plus a signal. ; Take the maximum and minimum output values ​​of the judgment module; Add 1 to the minimum output value, subtract the maximum output value, multiply by 1 / 2, and then multiply by the signal. Add them together to obtain the initial modulated wave signal. .

[0011] In conjunction with the first aspect, in some embodiments, the method for generating the driving signal for the zero-crossing interval in the zero-crossing interval adjustment step includes: Compare the first modulation wave signal of phase i. With positive carrier Size; If the first modulation wave signal of phase i Greater than or equal to positive carrier Then assign 1 to the first intermediate signal S of phase i. i1x If the first modulation wave signal of phase i Less than positive carrier Then assign 0 to the first intermediate signal S of phase i. i1x ; Compare the first modulation wave signal of phase i. With load wave Size; If the first modulation wave signal of phase i Greater than or equal to load wave Then assign 1 to the second intermediate signal S of phase i. i2x If the first modulation wave signal of phase i Less than load wave Then assign 0 to the second intermediate signal S of phase i. i2x ; Compare the initial modulation signal v of phase i ti With positive carrier Size; If the initial modulation signal of phase i is v ti Less than positive carrier Then assign 1 to the third intermediate signal S of phase i. i3x Assign 0 to the fifth intermediate signal S of phase i. i1y If the initial modulation signal of phase i is v ti Greater than or equal to positive carrier Then assign 0 to the third intermediate signal S of phase i. i3x Assign 1 to the fifth intermediate signal S of phase i. i1y ; Compare the initial modulation signal v of phase i ti With load wave Size; If the initial modulation signal of phase i is v ti Less than load wave Then assign 1 to the fourth intermediate signal S of phase i. i4x Assign 0 to the sixth intermediate signal S of phase i. i2y If the initial modulation signal of phase i is v ti Greater than or equal to load wave Then assign 0 to the fourth intermediate signal S of phase i. i4x Assign 1 to the sixth intermediate signal S of phase i. i2y ; Compare the second modulation wave signal of phase i. With positive carrier Size; If the second modulation wave signal of phase i Less than positive carrier Then assign 1 to the seventh intermediate signal S of phase i. i3y If the second modulation wave signal of phase i Greater than or equal to positive carrier Then assign 0 to the seventh intermediate signal S of phase i. i3y ; Compare the second modulation wave signal of phase i. With load wave Size; If the second modulation wave signal of phase i Less than load wave Then assign 1 to the eighth intermediate signal S of phase i. i4y If the second modulation wave signal of phase i Greater than or equal to load wave Then assign 0 to the eighth intermediate signal S of phase i. i4y ; Determine the i-phase grid current I i Is it greater than 0? If the i-phase grid current I i If the value is greater than 0, then the first intermediate signal S of phase i will be... i1x The value is assigned to the first driving signal S of phase i in the zero-crossing interval. i11 Assign S to the second intermediate signal of phase i. i2x The i-phase second drive signal S passing through the zero-point interval is given. i12 The third intermediate signal S of phase i i3x The value is assigned to the i-phase third driving signal S in the zero-crossing interval. i13 The fourth intermediate signal S of phase i i4x The value is assigned to the i-phase fourth driving signal S in the zero-crossing interval. i14 If the i-phase grid current I i If the value is less than or equal to 0, then the fifth intermediate signal S of phase i will be... i1y The value is assigned to the first driving signal S of phase i in the zero-crossing interval. i11 Assign the sixth intermediate signal of phase i to S i2y The i-phase second drive signal S passing through the zero-point interval is given. i12 The seventh intermediate signal S of phase i i3y The value is assigned to the i-phase third driving signal S in the zero-crossing interval. i13 The eighth intermediate signal S of phase i i4y The value is assigned to the i-phase fourth driving signal S in the zero-crossing interval. i14 .

[0012] In conjunction with the first aspect, in some embodiments, the method for generating the driving signal for the non-zero-crossing interval in the non-zero-crossing interval modulation step includes: Compare the initial modulation signal v of phase i ti With positive carrier Size; If the initial modulation signal of phase i is v ti Greater than or equal to positive carrier Then assign 1 to the first intermediate signal S of phase i. i1x If the initial modulation signal of phase i is v ti Less than positive carrier Then assign 0 to the first intermediate signal S of phase i. i1x For the first intermediate signal S of phase i i1xInverting the signal yields the third intermediate signal S of phase i. i3x ; Compare the initial modulation signal v of phase i ti With load wave Size; If the initial modulation signal of phase i is v ti Greater than or equal to load wave Then assign 1 to the second intermediate signal S of phase i. i2x If the initial modulation signal of phase i is v ti Less than load wave Then assign 0 to the second intermediate signal S of phase i. i2x For the second intermediate signal S of phase i i2x Inverting the signal yields the fourth intermediate signal S of phase i. i4x ; Determine the i-phase grid current I i Is it greater than 0? If the i-phase grid current I i If the value is greater than 0, then 0 is assigned to the first driving signal S of phase i in the non-zero-crossing interval. i21 and i-phase second drive signal S i22 The third intermediate signal S of phase i i3x The value is assigned to the i-phase third driving signal S in the non-zero-crossing interval. i23 The fourth intermediate signal S of phase i i4x The value is assigned to the fourth driving signal S of phase i in the non-zero-crossing interval. i24 If the i-phase grid current I i If the value is less than or equal to 0, then the first intermediate signal S of phase i will be... i1x The first driving signal S of phase i, assigned to the non-zero-crossing interval i21 Assign S to the second intermediate signal of phase i. i2x The second driving signal S of phase i in the non-zero-crossing interval i22 Then, assign 0 to the i-phase third driving signal S in the non-zero-crossing interval. i23 and the fourth driving signal S of phase i i24 .

[0013] In conjunction with the first aspect, in some embodiments, the method for selecting the drive signal for generating the SiC MOSFET power switching device in the air conditioner compressor drive rectifier in the drive signal selection step includes: The absolute values ​​of the three-phase grid currents are obtained by performing absolute value calculations. Determine whether the absolute value of the three-phase power grid current is greater than 1; If the absolute value of the three-phase grid current is greater than 1, then the drive signal in the zero-crossing interval is selected as the drive signal of the SiC MOSFET power switching device in the air conditioner compressor drive rectifier. If the absolute value of the three-phase grid current is less than or equal to 1, then the drive signal in the non-zero-crossing interval is selected as the drive signal for the SiC MOSFET power switching device in the air conditioner compressor drive rectifier.

[0014] A second aspect of this application provides a SiC device air conditioner compressor drive rectifier control system for implementing the SiC device air conditioner compressor drive rectifier control method described in the first aspect of this application, comprising: The grid voltage angle extraction module transforms the three-phase grid voltage into dq-axis grid voltage based on the grid voltage phase angle θ1, and updates the grid voltage phase angle θ1 based on the q-axis grid voltage. The current command generation module generates a DC-side reference voltage. With the actual DC side voltage u dc The difference is used to obtain the d-axis reference current through PI adjustment. ; The current conversion module converts the three-phase grid current into dq-axis grid current based on the grid voltage phase angle θ1. The inner loop control module is based on PI regulation, according to the d-axis reference current. The dq-axis grid current and dq-axis grid voltage generate the dq-axis voltage modulation signal; A three-phase modulated wave generation module, based on the actual DC-side voltage u dc The phase angle θ1 of the grid voltage is used to generate a three-phase modulated wave signal based on the dq-axis voltage modulation signal; The three-phase modulation wave conversion module combines and transforms the three-phase modulation wave signals to generate the initial modulation wave signal. ; The zero-crossing interval modulation module modulates the lower DC bus capacitor voltage u. dc2 Subtract the DC bus capacitor voltage u dc1 Obtain the balanced signal n p Balanced signal n p Add initial modulation wave signal Obtain the three-phase initial wave modulation signal; subtract 4T from the i-phase initial wave modulation signal. u f s Obtain the first modulation wave signal of phase i. The initial modulation wave signal of phase i is added with 4T u f s Obtain the i-phase second modulation wave signal Where i = a, b, c, T u f is the driving pulse interval adjustment coefficient. s The switching frequency; based on the three-phase initial wave modulation signal, the three-phase first modulation wave signal, and the three-phase second modulation wave signal. , positive carrier Load wave The magnitude of the three-phase grid current generates the driving signal for the zero-crossing interval; Non-zero-crossing interval modulation module, based on three-phase initial modulation signal and positive carrier. Load wave The magnitude of the three-phase grid current generates a drive signal in the non-zero-crossing range; The drive signal selection module selects and generates drive signals for the SiC MOSFET power switching devices in the air conditioner compressor drive rectifier based on the magnitude of the absolute value of the three-phase grid current and the drive signals in the zero-crossing interval and the non-zero-crossing interval.

[0015] Compared with the prior art, the advantages and positive effects of this application are as follows: The SiC device air conditioner compressor drive rectifier control method and system proposed in this application divides the entire fundamental frequency cycle into zero-crossing and non-zero-crossing intervals. Different control methods are employed in different intervals, leveraging the advantages of each method to improve the efficiency and harmonic performance of the SiC device air conditioner compressor drive rectifier. In the non-zero-crossing interval, the SiC MOSFET itself with its anti-parallel diode and the additionally added SiC Schottky diode work together, while the SiC MOSFET itself does not operate. The parallel current path reduces conduction losses and improves rectifier efficiency. Even without adding a dead zone, it can avoid rectifier shoot-through short circuits, effectively suppressing dead zone effects and reducing current distortion. In the zero-crossing interval, the SiC MOSFET participates in operation, reducing current distortion at the zero-crossing point, improving the sinusoidal nature of the overall current, and increasing the output current command. This reduces current and harmonics when dealing with non-unity power factor operating conditions. Attached Figure Description

[0016] Figure 1 This is a topology diagram of the main circuit of the SiC device air conditioner compressor drive rectifier according to an embodiment of this application; Figure 2 This is a flowchart of the SiC device air conditioner compressor drive rectifier control method described in the embodiments of this application; Figure 3 This is a schematic diagram illustrating the principle of power grid voltage angle extraction in an embodiment of this application. Figure 4 This is a schematic diagram of the current command generation for an embodiment of this application; Figure 5 This is a schematic diagram of the current transformation in an embodiment of this application; Figure 6 This is a schematic diagram of the control inner loop in an embodiment of this application; Figure 7 This is a schematic diagram illustrating the principle of three-phase modulation wave generation according to an embodiment of this application; Figure 8 This is a schematic diagram of the three-phase modulation wave transformation according to an embodiment of this application; Figure 9 This is a schematic diagram of the zero-crossing interval modulation in an embodiment of this application; Figure 10 This is a schematic diagram of the non-zero-crossing interval modulation in an embodiment of this application; Figure 11 This is a schematic diagram of the drive signal selection in an embodiment of this application; Figure 12 This is a structural block diagram of the SiC device air conditioner compressor drive rectifier control system according to an embodiment of this application; Figure 13 A schematic diagram of the three-phase current waveform and total harmonic distortion of the current using a traditional control method with dead zones; Figure 14 This is a schematic diagram of the three-phase current waveform and total harmonic distortion rate using the method and system described in this application. Detailed Implementation

[0017] The present application will now be described in detail with reference to the accompanying drawings through exemplary embodiments. However, it should be understood that, without further description, elements, structures, and features in one embodiment may be advantageously incorporated into other embodiments.

[0018] Figure 1 The diagram shows the main circuit of the air conditioner compressor driving the rectifier. In the main circuit: u dc The actual DC side voltage, u dc1 The voltage of the upper DC bus capacitor, u dc2 C1 is the lower DC bus capacitor voltage, C2 is the upper DC bus capacitor, and C2 is the lower DC bus capacitor. A1 Q A2 Q A3 Q A4 For the SiC MOSFET power switching device of phase a bridge arm, D A1 D A2 D A3 D A4 For the SiC Schottky diode of phase a bridge arm, L A1 L A2 L is the separating inductance for phase a bridge arm. A Q is the filter inductor for phase a. B1 Q B2 Q B3 Q B4 For the b-phase bridge arm, a SiC MOSFET power switch device, D B1 D B2 D B3 D B4 For the b-phase bridge arm, there is a SiC Schottky diode, L B1 L B2 L is the separating inductor for phase b bridge arm.B This is the b-phase filter inductor. Q C1 Q C2 Q C3 Q C4 For the SiC MOSFET power switching device of the c-phase bridge arm, D C1 D C2 D C3 D C4 For the c-phase bridge arm, the SiC Schottky diode, L C1 L C2 L is the separating inductor for the c-phase bridge arm. C This is the c-phase filter inductor. E a E b E c For the three-phase power grid voltage, I a I b I c The current is the three-phase mains current. R is the resistance simulating the load of the air conditioner inverter and compressor.

[0019] Since the three phase bridge arms in the main circuit are completely symmetrical, the connection method is explained using phase a as an example. See also... Figure 1 The upper DC bus capacitor C1 and the lower DC bus capacitor C2 are connected at point O; SiC MOSFET power switching device Q A1 One end of the drain is connected to the upper DC bus capacitor C1 through point P. The SiC MOSFET power switch Q... A1 Source and SiC Schottky diode D A4 Cathode through X A2 Point connection, SiC Schottky diode D A4 The other end of the anode is connected to the lower DC bus capacitor C2 through point N; SiC MOSFET power switch Q A2 Drain and SiC Schottky diode D A3 The cathode is connected via point O, and the SiC MOSFET power switch Q is... A2 Source and SiC Schottky diode D A2 Anode through X A4 Point connection, SiC Schottky diode D A2 Cathode and segmented inductor L A2 Through X A2 Point connection; SiC MOSFET power switching device Q A3 Source and SiC Schottky diode D A3 Anode through X A5 Point connection, SiC MOSFET power switching device Q A3 Drain and split inductor L A1 Through X A3 Point connection, split inductor LA1 The other end is connected to the split inductor L A2 Through X A1 Point connection; SiC MOSFET power switching device Q A4 Drain and SiC Schottky diode D A1 Anode through X A3 Point connection, SiC MOSFET power switching device Q A4 The source capacitor C2 is connected to the lower DC bus capacitor at point N; the segmented inductor L A1 With phase a filter inductor L A Through X A1 Point connection, phase a filter inductor L A The other end is connected to the phase a grid voltage E a Direct connection. The connection method of phase b and phase c bridge arms is the same as that of phase a bridge arm, and will not be described again here.

[0020] Regarding the aforementioned air conditioning compressor drive rectifier, this application provides a SiC device air conditioning compressor drive rectifier control method and system, which divides the entire fundamental frequency period into zero-crossing intervals and non-zero-crossing intervals, and adopts different control methods in different intervals, thereby utilizing the advantages of different control methods to improve the efficiency and harmonic performance of the SiC device air conditioning compressor drive rectifier.

[0021] The following describes in detail the control method and system for driving the rectifier of the air conditioner using SiC devices described in this application, with reference to the accompanying drawings and embodiments.

[0022] See Figure 2 The first aspect of this application provides a method for controlling a SiC device air conditioner compressor driving a rectifier, including: S1. Steps for extracting grid voltage angle: See [link / details] Figure 3 Based on the grid voltage phase angle θ1, the three-phase grid voltage is transformed into a dq-axis grid voltage, and based on the q-axis grid voltage e... q Update the grid voltage phase angle θ1.

[0023] Specifically, in one embodiment of this application, see also: Figure 3 Methods for converting three-phase grid voltage to dq-axis grid voltage include: Phase a grid voltage E a Subtract the first set coefficient and multiply by the b-phase grid voltage E b Subtract the first set coefficient and multiply by the c-phase grid voltage E c Then, multiply by the second set coefficient to obtain the α-axis grid voltage E. α ; The third set coefficient is multiplied by the phase b grid voltage E. b Subtract the third set coefficient and multiply by the c-phase grid voltage E cThen, multiply by the second set coefficient to obtain the β-axis grid voltage E. β ; α-axis grid voltage E α The product of cosθ1 and the β-axis grid voltage E β Multiplying by sinθ1, we obtain the d-axis grid voltage e in the two-phase coordinate system. d α-axis grid voltage E α Multiply by -sinθ1 and add the β-axis grid voltage E β Multiplying by cosθ1, we obtain the q-axis grid voltage e in the two-phase coordinate system. q .

[0024] In this embodiment, the conversion from three-phase voltage to the αβ axis is achieved through hierarchical weighted calculation, and then the transformation from the αβ axis to the dq axis is realized by combining angle calculation, converting the coupled alternating three-phase grid voltage into a decoupled DC dq-axis voltage component. On the one hand, this effectively reduces the impact of instantaneous grid disturbances and random noise on single-phase signals. The transformed DC signal has small fluctuations and is less susceptible to short-term grid voltage fluctuations and electromagnetic interference, ensuring the continuous and stable operation of the subsequent control system. On the other hand, it accurately extracts the grid voltage amplitude and phase information. The angle θ1 is introduced into the Park calculation during the transformation process, and the angle parameter can be updated in real time in conjunction with the grid phase to achieve dynamic tracking of the grid voltage phase. Relying on the stable dq-axis grid voltage component, precise phase locking can be achieved, ensuring that the converter, grid-connected equipment, etc., are synchronized with the grid voltage phase, and suppressing harmonic and impact problems caused by phase deviation.

[0025] In this embodiment, the first setting coefficient is 0.5, the second setting coefficient is 0.816, and the third setting coefficient is 0.866. It should be noted that the first, second, and third setting coefficients can be set according to actual needs.

[0026] Specifically, in one embodiment of this application, see also: Figure 3 Based on the q-axis grid voltage e q Methods for updating the grid voltage phase angle θ1 include: Calculate the grid voltage e along the 0 and q axes. q The difference is used to obtain the first voltage difference; The first voltage difference is passed through a transfer function K. PI1 After the first PI controller with value = 0.25 + 0.35 / s performs PI adjustment, the first intermediate value is obtained; Integrating the difference obtained by subtracting the first intermediate value from 100π, we obtain the grid voltage phase angle θ1.

[0027] In this embodiment of the application, on the one hand, the q-axis grid voltage e qAs a phase deviation feedback quantity, the phase deviation signal is obtained by calculating its difference from zero, thus constructing a complete closed-loop regulation link. It can sense the grid voltage phase offset in real time and continuously correct the grid voltage phase angle θ1 to ensure that the phase follows the target value change, achieving automatic grid phase tracking. On the other hand, the PI regulation uses a proportional-integral controller (transfer function K... PI1 =0.25+0.35 / s), the proportional element can quickly respond to phase deviation and shorten the dynamic adjustment time, while the integral element can completely eliminate steady-state phase error. When facing small-amplitude phase drift and short-term disturbances in the power grid, the q-axis grid voltage e can be... q The phase adjustment is kept stable near zero to ensure accuracy. Furthermore, using 100π as the reference angular frequency component, the adjustment value is superimposed and integrated to generate the grid voltage phase angle θ1. The integration process ensures continuous, non-abrupt phase signal variation, conforming to the sinusoidal grid voltage phase change pattern and effectively avoiding problems such as current surges and increased harmonics caused by sudden phase changes.

[0028] S2. Current command generation steps: See [link / details] Figure 4 DC side reference voltage With the actual DC side voltage u dc The difference is used to obtain the d-axis reference current through PI adjustment. .

[0029] In this embodiment, the DC-side voltage deviation is used as input, and a d-axis reference current is generated through PI regulation to form the outer loop control of the voltage closed loop. This can quickly suppress voltage disturbances, eliminate steady-state errors, and stabilize the DC bus voltage. It can also achieve a smooth conversion from voltage control to current command, and work with the inner loop to complete active power regulation. The system has fast dynamic response, high control accuracy, and strong operational stability.

[0030] Specifically, in one embodiment of this application, see also: Figure 4 , obtain the d-axis reference current The methods include: Calculate the difference between the DC-side reference voltage and the DC-side actual voltage to obtain the second voltage difference; The second voltage difference is passed through a transfer function K. PI2 After the second PI regulator (=0.4+40 / s) performs PI adjustment, the d-axis reference current is obtained. .

[0031] In this embodiment, the PI control employs a proportional-integral controller (transfer function K). PI2=0.4+40 / s), this regulator combines proportional and integral functions. The proportional element responds quickly to voltage deviations and accelerates dynamic adjustment; the integral element completely eliminates steady-state voltage errors, avoids long-term deviations of DC voltage from the reference value, and significantly improves the control accuracy of DC bus voltage.

[0032] S3. Current transformation steps: Based on the grid voltage phase angle θ1, the three-phase grid current is transformed into the dq-axis grid current.

[0033] Specifically, in one embodiment of this application, see [link to embodiment]. Figure 5 Methods for converting three-phase grid current into dq-axis grid current include: Phase a grid current I a Multiply by sinθ1 by the fourth set coefficient, then add the b-phase grid current I. b Multiply by sin(θ1-2π / 3), then add the c-phase grid current I. c Multiplying by sin(θ1+2π / 3) yields the d-axis grid current i. d ; Phase a grid current I a Multiply by cosθ1 by the fourth constant coefficient, then add the b-phase grid current I. b Multiply by cos(θ1-2π / 3), then add the c-phase grid current I. c Multiplying by cos(θ1+2π / 3) yields the q-axis grid current i. q .

[0034] In this embodiment, relying on the real-time phase angle θ1 and the set coefficient, the three-phase grid current is converted into decoupled dq-axis current components through trigonometric function weighting calculation, which accurately distinguishes active and reactive currents and can weaken the impact of single-channel current sampling noise and instantaneous pulse interference. Under steady state, the dq-axis current fluctuation is small, which can provide stable feedback for the closed-loop control of the current inner loop, thereby improving the current control accuracy and operational stability of the whole machine.

[0035] In this embodiment, the fourth setting coefficient is 0.667. It should be noted that the fourth setting coefficient can be set according to actual needs.

[0036] S4. Control inner loop steps: Based on PI regulation, according to the d-axis reference current. The dq-axis grid current and dq-axis grid voltage generate the dq-axis voltage modulation signal.

[0037] Specifically, in one embodiment of this application, see [link to embodiment]. Figure 6 Methods for generating dq-axis voltage modulation signals include: Reference current for the d-axis Reduce d-axis grid current i dThe difference is used to obtain a second intermediate value through PI adjustment, and the q-axis grid current i is reduced from 0. q The difference is used to obtain the third intermediate value through PI regulation; the PI regulation adopts a PI controller with a transfer function of 16+10 / s; d-axis grid voltage e d Subtract the second intermediate value, then add the q-axis grid current i. q The product of 314L and 314L yields the d-axis voltage modulation signal. Where L is the inductance, L = L A =L B =L C ; q-axis grid voltage e q Subtract the third intermediate value, then subtract the d-axis grid current i. d The product of 314L and 314L yields the q-axis voltage modulation signal. .

[0038] In this embodiment, on the one hand, the deviations between the d-axis and q-axis reference currents and the actual grid current are used as adjustment inputs. A closed-loop calculation is completed through PI control to quickly suppress dynamic current deviations and eliminate steady-state errors through integral action, ensuring that the actual current stably follows the reference command and guaranteeing current control accuracy. On the other hand, the product of 314L and the dq-axis current is added as a cross-decoupling component to specifically counteract the coupling effect between the d-axis and q-axis voltages and currents in the dq coordinate system. This breaks the problem of mutual interference between the two axes, making the d-axis and q-axis control independent and significantly reducing control deviations caused by coupling.

[0039] S5. Three-phase modulated wave generation steps: Based on the actual DC side voltage u dc The phase angle θ1 of the grid voltage is used to generate a three-phase modulated wave signal based on the dq-axis voltage modulation signal.

[0040] Specifically, in one embodiment of this application, see [link to embodiment]. Figure 7 Methods for generating three-phase modulated wave signals include: d-axis voltage modulation signal Multiply by 2 and divide by the actual DC side voltage u dc The first intermediate voltage modulation signal is obtained. q-axis voltage modulation signal Multiply by 2 and divide by the actual DC side voltage u dc The second intermediate voltage modulation signal is obtained. ; First intermediate voltage modulation signal The product of sinθ1 and the second intermediate voltage modulation signal Multiplying by cosθ1 yields the phase a modulated wave signal. First intermediate voltage modulation signal The product of sin(θ1-2π / 3) and the second intermediate voltage modulation signal Multiplying by cos(θ1-2π / 3) yields the phase b modulated wave signal. First intermediate voltage modulation signal The product of sin(θ1+2π / 3) and the second intermediate voltage modulation signal Multiplying by cos(θ1+2π / 3) yields the c-phase modulated wave signal. .

[0041] In this embodiment of the application, on the one hand, the dq axis modulation signal is multiplied by 2 and divided by the actual DC side voltage u. dc This completes the normalization of the modulation coefficients. It can compensate for DC bus voltage fluctuations in real time, avoiding fluctuations caused by the actual DC side voltage u. dc The rise and fall of the modulation wave amplitude causes abnormalities. This ensures the modulation depth remains within a reasonable range, preventing overmodulation and output voltage distortion. On the other hand, using the real-time phase angle θ1 as a reference, trigonometric weighted calculations restore the decoupled dq-axis voltage modulation signal to a three-phase modulation wave signal, achieving coordinate inversion and matching the drive requirements of the subsequent three-phase bridge converter circuit, thus completing the connection between the control signal and the main circuit. The calculation process strictly follows the three-phase phase relationship of θ1 and θ1±2π / 3 to generate the a, b, and c phase modulation waves. The three-phase signals have a 120° phase difference, resulting in high waveform symmetry, which effectively suppresses three-phase output imbalance and reduces harmonic content.

[0042] S6. Three-phase modulation wave transformation steps: Combine and transform the three-phase modulation wave signals to generate the initial modulation wave signal. .

[0043] Specifically, in one embodiment of this application, see [link to embodiment]. Figure 8 Generate the initial modulation wave signal The methods include: Combine the three-phase modulated wave signals into a signal. ; Multiply the signal by the fifth set coefficient to obtain the signal. ; The signal is determined by the judgment module. Is it greater than 0? If signal If the value is greater than 0, then the output of the determination module is a signal. ;if signal If the value is less than 0, the output of the judgment module is 1 plus a signal. ; Take the maximum and minimum output values ​​of the judgment module; Add 1 to the minimum output value, subtract the maximum output value, multiply by 1 / 2, and then multiply by the signal. Add them together to obtain the initial modulated wave signal. .

[0044] In this embodiment of the application, on the one hand, the three three-phase modulated waves are integrated into a single signal. Then, by using the fifth set coefficient for overall amplitude scaling, the overall gain of the modulation wave can be uniformly adjusted to flexibly match the control requirements of different power levels and different output conditions, demonstrating strong adaptability. On the other hand, relying on the judgment module to perform differentiated calculations on positive and negative signals, and performing bias compensation on negative signals, combined with extreme value extraction and linear operations, the overall signal range is reconstructed, converting the original modulation signal into the effective working range and avoiding problems such as negative signal values ​​and amplitude out-of-bounds errors. Furthermore, through extreme value calculations and secondary correction calculations, the amplitude of the modulation signal is balanced, making the modulation wave adapt to the PWM carrier modulation requirements, effectively suppressing waveform distortion, and improving the output power quality.

[0045] In this embodiment, the fifth setting coefficient is 1.155. It should be noted that the fifth setting coefficient can be set according to actual needs.

[0046] S7. Zero-crossing interval modulation steps: Lower DC bus capacitor voltage u dc2 Subtract the DC bus capacitor voltage u dc1 Obtain the balanced signal n p Balanced signal n p Add initial modulation wave signal The three-phase initial wave modulation signal is obtained; the i-phase initial modulation wave signal is reduced by 4T. u f s Obtain the first modulation wave signal of phase i. The initial modulation wave signal of phase i is added with 4T u f s Obtain the i-phase second modulation wave signal Where i = a, b, c, T u f is the driving pulse interval adjustment coefficient. s The switching frequency; based on the three-phase initial wave modulation signal, the three-phase first modulation wave signal, and the three-phase second modulation wave signal. , positive carrier Load wave The magnitude of the three-phase grid current generates the driving signal for the zero-crossing interval.

[0047] Specifically, in one embodiment of this application, the method for generating a driving signal crossing the zero-crossing interval includes: Compare the first modulation wave signal of phase i. With positive carrier Size; If the first modulation wave signal of phase i Greater than or equal to positive carrier Then assign 1 to the first intermediate signal S of phase i.i1x If the first modulation wave signal of phase i Less than positive carrier Then assign 0 to the first intermediate signal S of phase i. i1x ; Compare the first modulation wave signal of phase i. With load wave Size; If the first modulation wave signal of phase i Greater than or equal to load wave Then assign 1 to the second intermediate signal S of phase i. i2x If the first modulation wave signal of phase i Less than load wave Then assign 0 to the second intermediate signal S of phase i. i2x ; Compare the initial modulation signal v of phase i ti With positive carrier Size; If the initial modulation signal of phase i is v ti Less than positive carrier Then assign 1 to the third intermediate signal S of phase i. i3x Assign 0 to the fifth intermediate signal S of phase i. i1y If the initial modulation signal of phase i is v ti Greater than or equal to positive carrier Then assign 0 to the third intermediate signal S of phase i. i3x Assign 1 to the fifth intermediate signal S of phase i. i1y ; Compare the initial modulation signal v of phase i ti With load wave Size; If the initial modulation signal of phase i is v ti Less than load wave Then assign 1 to the fourth intermediate signal S of phase i. i4x Assign 0 to the sixth intermediate signal S of phase i. i2y If the initial modulation signal of phase i is v ti Greater than or equal to load wave Then assign 0 to the fourth intermediate signal S of phase i. i4x Assign 1 to the sixth intermediate signal S of phase i. i2y ; Compare the second modulation wave signal of phase i. With positive carrier Size; If the second modulation wave signal of phase i Less than positive carrier Then assign 1 to the seventh intermediate signal S of phase i. i3y If the second modulation wave signal of phase i Greater than or equal to positive carrier Then assign 0 to the seventh intermediate signal S of phase i. i3y ; Compare the second modulation wave signal of phase i. With load wave Size; If the second modulation wave signal of phase i Less than load wave Then assign 1 to the eighth intermediate signal S of phase i. i4y If the second modulation wave signal of phase i Greater than or equal to load wave Then assign 0 to the eighth intermediate signal S of phase i. i4y ; Determine the i-phase grid current I i Is it greater than 0? If the i-phase grid current I i If the value is greater than 0, then the first intermediate signal S of phase i will be... i1x The value is assigned to the first driving signal S of phase i in the zero-crossing interval. i11 Assign S to the second intermediate signal of phase i. i2x The i-phase second drive signal S passing through the zero-point interval is given. i12 The third intermediate signal S of phase i i3x The value is assigned to the i-phase third driving signal S in the zero-crossing interval. i13 The fourth intermediate signal S of phase i i4x The value is assigned to the i-phase fourth driving signal S in the zero-crossing interval. i14 If the i-phase grid current I i If the value is less than or equal to 0, then the fifth intermediate signal S of phase i will be... i1y The value is assigned to the first driving signal S of phase i in the zero-crossing interval. i11 Assign the sixth intermediate signal of phase i to S i2y The i-phase second drive signal S passing through the zero-point interval is given. i12 The seventh intermediate signal S of phase i i3y The value is assigned to the i-phase third driving signal S in the zero-crossing interval. i13 The eighth intermediate signal S of phase i i4y The value is assigned to the i-phase fourth driving signal S in the zero-crossing interval. i14 .

[0048] In this embodiment, a voltage balance signal np is obtained by subtracting the voltage of the lower bus capacitor from the voltage of the upper bus capacitor, and this signal is superimposed on the initial modulation wave. The modulation waveform can be dynamically corrected based on the voltage deviation between the two capacitors, compensating for voltage imbalance in real time, effectively suppressing voltage division offset of the bus capacitors, avoiding overvoltage and accelerated aging of a single capacitor, and ensuring long-term stable operation of the DC bus unit. (Based on 4T...) u fs As the offset, the initial modulation wave of each phase is added or subtracted to obtain the first and second offset modulation signals. This is based on the drive pulse interval adjustment coefficient T. u With switching frequency f s Precise control of offset amplitude allows for flexible adjustment of pulse distribution range. By combining multi-dimensional signals from three-phase initial modulation waves, two-channel offset modulation waves, positive load waves, and three-phase grid current, the voltage / current zero-crossing interval is accurately located. Specialized processing is implemented for the zero-crossing point, a special region prone to distortion and spike interference. The control logic is clearly layered, resulting in high discrimination accuracy. This not only solves the problem of uneven bus voltage distribution but also optimizes the zero-crossing switching sequence, suppresses harmonics and electromagnetic interference, and eliminates bridge arm shoot-through faults. Parameters are flexibly adjustable, and computation is highly efficient, effectively improving equipment operational safety and output power quality.

[0049] Specifically, see Figure 9 Methods for generating phase a driving signal in the zero-crossing interval include: Compare the first modulation wave signal of phase a With positive carrier Size; If the first modulation wave signal of phase a Greater than or equal to positive carrier Then assign 1 to the first intermediate signal S of phase a. a1x If the first modulation wave signal of phase a Less than positive carrier Then assign 0 to the first intermediate signal S of phase a. a1x ; Compare the first modulation wave signal of phase a With load wave Size; If the first modulation wave signal of phase a Greater than or equal to load wave Then assign 1 to the second intermediate signal S of phase a. a2x If the first modulation wave signal of phase a Less than load wave Then assign 0 to the second intermediate signal S of phase a. a2x ; Compare the initial modulation signal v of phase a ta With positive carrier Size; If the initial modulation signal of phase a is v ta Less than positive carrier Then assign 1 to the third intermediate signal S of phase a. a3x Assign 0 to the fifth intermediate signal S of phase a. a1y If the initial modulation signal of phase a is v ta Greater than or equal to positive carrier Then assign 0 to the third intermediate signal S of phase a. a3x Assign 1 to the fifth intermediate signal S of phase a. a1y ; Compare the initial modulation signal v of phase a ta With load wave Size; If the initial modulation signal of phase a is v ta Less than load wave Then assign 1 to the fourth intermediate signal S of phase a. a4x Assign 0 to the sixth intermediate signal S of phase a. a2y If the initial modulation signal of phase a is v ta Greater than or equal to load wave Then assign 0 to the fourth intermediate signal S of phase a. a4x Assign 1 to the sixth intermediate signal S of phase a. a2y ; Compare the second modulation wave signal of phase a With positive carrier Size; If the second modulation wave signal of phase a Less than positive carrier Then assign 1 to the seventh intermediate signal S of phase a. a3y If the second modulation wave signal of phase a Greater than or equal to positive carrier Then assign 0 to the seventh intermediate signal S of phase a. a3y ; Compare the second modulation wave signal of phase a With load wave Size; If the second modulation wave signal of phase a Less than load wave Then assign 1 to the eighth intermediate signal S of phase a. a4y If the second modulation wave signal of phase a Greater than or equal to load wave Then assign 0 to the eighth intermediate signal S of phase a. a4y ; Determine the current I in phase a of the power grid a Is it greater than 0? If the grid current of phase a is I a If it is greater than 0, then the first intermediate signal S of phase a will be... a1x The first driving signal S of phase a in the zero-crossing interval is assigned a value. a11 Assign S to the second intermediate signal of phase a. a2x The second driving signal S of phase a passing through the zero-point interval is given. a12 The third intermediate signal S of phase a a3x The value is assigned to the third driving signal S of phase a in the zero-crossing interval. a13The fourth intermediate signal S of phase a a4x The value is assigned to the fourth driving signal S of phase a in the zero-crossing interval. a14 If the grid current I in phase a a If the value is less than or equal to 0, then the fifth intermediate signal S of phase a will be... a1y The first driving signal S of phase a in the zero-crossing interval is assigned a value. a11 Assign the value S to the sixth intermediate signal of phase a. a2y The second driving signal S of phase a passing through the zero-point interval is given. a12 The seventh intermediate signal S of phase a a3y The value is assigned to the third driving signal S of phase a in the zero-crossing interval. a13 The eighth intermediate signal S of phase a a4y The value is assigned to the fourth driving signal S of phase a in the zero-crossing interval. a14 .

[0050] Specifically, see [link to relevant documentation] Figure 9 Methods for generating the b-phase drive signal in the zero-crossing interval include: Compare the first modulation wave signal of phase b. With positive carrier Size; If the first modulation wave signal of phase b Greater than or equal to positive carrier Then assign 1 to the first intermediate signal S of phase b. b1x If the first modulation wave signal of phase b Less than positive carrier Then assign 0 to the first intermediate signal S of phase b. b1x ; Compare the first modulation wave signal of phase b. With load wave Size; If the first modulation wave signal of phase b Greater than or equal to load wave Then assign 1 to the second intermediate signal S of phase b. b2x If the first modulation wave signal of phase b Less than load wave Then assign 0 to the second intermediate signal S of phase b. b2x ; Compare the initial modulation signal v of phase b tb With positive carrier Size; If the initial modulation signal of phase b is v tb Less than positive carrier Then assign 1 to the third intermediate signal S of phase b. b3x Assign 0 to the fifth intermediate signal S of phase b. b1y If the initial modulation signal of phase b is v tbGreater than or equal to positive carrier Then assign 0 to the third intermediate signal S of phase b. b3x Assign 1 to the fifth intermediate signal S of phase b. b1y ; Compare the initial modulation signal v of phase b tb With load wave Size; If the initial modulation signal of phase b is v tb Less than load wave Then assign 1 to the fourth intermediate signal S of phase b. b4x Assign 0 to the sixth intermediate signal S of phase b. b2y If the initial modulation signal of phase b is v tb Greater than or equal to load wave Then assign 0 to the fourth intermediate signal S of phase b. b4x Assign 1 to the sixth intermediate signal S of phase b. b2y ; Compare the second modulation wave signal of phase b. With positive carrier Size; If the second modulation wave signal of phase b Less than positive carrier Then assign 1 to the seventh intermediate signal S of phase b. b3y If the second modulation wave signal of phase b Greater than or equal to positive carrier Then assign 0 to the seventh intermediate signal S of phase b. b3y ; Compare the second modulation wave signal of phase b. With load wave Size; If the second modulation wave signal of phase b Less than load wave Then assign 1 to the eighth intermediate signal S of phase b. b4y If the second modulation wave signal of phase b Greater than or equal to load wave Then assign 0 to the eighth intermediate signal S of phase b. b4y ; Determine the phase b grid current I b Is it greater than 0? If the phase b grid current I b If the value is greater than 0, then the first intermediate signal S of phase b will be... b1x The value is assigned to the first driving signal S of phase b in the zero-crossing interval. b11 Assign S to the second intermediate signal of phase b. b2x The second drive signal S of phase b passing through the zero-point interval is given. b12 The third intermediate signal S of phase b b3xThe value is assigned to the b-phase third drive signal S in the zero-crossing interval. b13 The fourth intermediate signal S of phase b b4x The value is assigned to the fourth driving signal S of phase b in the zero-crossing interval. b14 If the grid current in phase b is I b If the value is less than or equal to 0, then the fifth intermediate signal S of phase b will be... b1y The value is assigned to the first driving signal S of phase b in the zero-crossing interval. b11 Assign the value S to the sixth intermediate signal of phase b. b2y The second drive signal S of phase b passing through the zero-point interval is given. b12 The seventh intermediate signal S of phase b b3y The value is assigned to the b-phase third drive signal S in the zero-crossing interval. b13 The eighth intermediate signal S of phase b b4y The value is assigned to the fourth driving signal S of phase b in the zero-crossing interval. b14 .

[0051] Specifically, see [link to relevant documentation] Figure 9 Methods for generating c-phase drive signals in the zero-crossing interval include: Compare the first modulation wave signal of phase c. With positive carrier Size; If the first modulation wave signal of phase c Greater than or equal to positive carrier Then assign 1 to the first intermediate signal S of phase c. c1x If the first modulation wave signal of phase c Less than positive carrier Then assign 0 to the first intermediate signal S of phase c. c1x ; Compare the first modulation wave signal of phase c. With load wave Size; If the first modulation wave signal of phase c Greater than or equal to load wave Then assign 1 to the second intermediate signal S of phase c. c2x If the first modulation wave signal of phase c Less than load wave Then assign 0 to the second intermediate signal S of phase c. c2x ; Compare the initial modulation signal v of phase c tc With positive carrier Size; If the initial modulation signal of phase c is v tc Less than positive carrier Then assign 1 to the third intermediate signal S of phase c. c3x Assign 0 to the fifth intermediate signal S of phase c. c1yIf the initial modulation signal of phase c is v tc Greater than or equal to positive carrier Then assign 0 to the third intermediate signal S of phase c. c3x Assign 1 to the fifth intermediate signal S of phase c. c1y ; Compare the initial modulation signal v of phase c tc With load wave Size; If the initial modulation signal of phase c is v tc Less than load wave Then assign 1 to the fourth intermediate signal S of phase c. c4x Assign 0 to the sixth intermediate signal S of phase c. c2y If the initial modulation signal of phase c is v tc Greater than or equal to load wave Then assign 0 to the fourth intermediate signal S of phase c. c4x Assign 1 to the sixth intermediate signal S of phase c. c2y ; Compare the second modulation wave signal of phase c. With positive carrier Size; If the second modulation wave signal of phase c Less than positive carrier Then assign 1 to the seventh intermediate signal S of phase c. c3y If the second modulation wave signal of phase c Greater than or equal to positive carrier Then assign 0 to the seventh intermediate signal S of phase c. c3y ; Compare the second modulation wave signal of phase c. With load wave Size; If the second modulation wave signal of phase c Less than load wave Then assign 1 to the eighth intermediate signal S of phase c. c4y If the second modulation wave signal of phase c Greater than or equal to load wave Then assign 0 to the eighth intermediate signal S of phase c. c4y ; Determine the c-phase grid current I c Is it greater than 0? If the c-phase grid current I c If the value is greater than 0, then the first intermediate signal S of phase c will be... c1x The value is assigned to the first driving signal S of phase c in the zero-crossing interval. c11 The second intermediate signal of phase c is assigned the value S. c2x The second drive signal S of phase c passing through the zero-point interval is given. c12The third intermediate signal S of phase c c3x The value is assigned to the c-phase third drive signal S in the zero-crossing interval. c13 The fourth intermediate signal S of phase c c4x The value is assigned to the fourth driving signal S of phase c in the zero-crossing interval. c14 If the c-phase grid current I c If the value is less than or equal to 0, then the fifth intermediate signal S of phase c will be... c1y The value is assigned to the first driving signal S of phase c in the zero-crossing interval. c11 Assign the value S to the sixth intermediate signal of phase c. c2y The second drive signal S of phase c passing through the zero-point interval is given. c12 The seventh intermediate signal S of phase c c3y The value is assigned to the c-phase third drive signal S in the zero-crossing interval. c13 The eighth intermediate signal S of phase c c4y The value is assigned to the fourth driving signal S of phase c in the zero-crossing interval. c14 .

[0052] S8. Non-zero-crossing interval modulation steps: Based on the three-phase initial modulation signal and the positive carrier... Load wave The magnitude of the three-phase grid current generates the driving signal in the non-zero-crossing interval.

[0053] Specifically, in one embodiment of this application, the method for generating a driving signal in a non-zero-crossing interval includes: Compare the initial modulation signal v of phase i ti With positive carrier Size; If the initial modulation signal of phase i is v ti Greater than or equal to positive carrier Then assign 1 to the first intermediate signal S of phase i. i1x If the initial modulation signal of phase i is v ti Less than positive carrier Then assign 0 to the first intermediate signal S of phase i. i1x For the first intermediate signal S of phase i i1x Inverting the signal yields the third intermediate signal S of phase i. i3x ; Compare the initial modulation signal v of phase i ti With load wave Size; If the initial modulation signal of phase i is v ti Greater than or equal to load wave Then assign 1 to the second intermediate signal S of phase i. i2x If the initial modulation signal of phase i is v ti Less than load wave Then assign 0 to the second intermediate signal S of phase i.i2x For the second intermediate signal S of phase i i2x Inverting the signal yields the fourth intermediate signal S of phase i. i4x ; Determine the i-phase grid current I i Is it greater than 0? If the i-phase grid current I i If the value is greater than 0, then 0 is assigned to the first driving signal S of phase i in the non-zero-crossing interval. i21 and i-phase second drive signal S i22 The third intermediate signal S of phase i i3x The value is assigned to the i-phase third driving signal S in the non-zero-crossing interval. i23 The fourth intermediate signal S of phase i i4x The value is assigned to the fourth driving signal S of phase i in the non-zero-crossing interval. i24 If the i-phase grid current I i If the value is less than or equal to 0, then the first intermediate signal S of phase i will be... i1x The first driving signal S of phase i, assigned to the non-zero-crossing interval i21 Assign S to the second intermediate signal of phase i. i2x The second driving signal S of phase i in the non-zero-crossing interval i22 Then, assign 0 to the i-phase third driving signal S in the non-zero-crossing interval. i23 and the fourth driving signal S of phase i i24 .

[0054] In this embodiment, multiple intermediate switching signals are generated by comparing the initial modulation signal with the positive carrier wave and the load wave, respectively. The upper and lower bridge arm drive signals are adaptively allocated based on the polarity of the grid current in each phase, and interlocking to zero is achieved. On the one hand, logic interlocking avoids direct short circuits in the SiC MOSFET in-phase bridge arms, ensuring the safety of power devices. On the other hand, lightweight carrier intersection logic is adopted to adapt to non-zero-crossing stable current conditions, reducing switching oscillations and electromagnetic interference. Each phase operates independently with low computational load and excellent real-time performance. It can be combined with a high-current zero-crossing drive strategy to achieve reliable control of the air conditioner compressor rectifier across the entire load range.

[0055] Specifically, see Figure 10 Methods for generating phase a driving signals in non-zero-crossing intervals include: Compare the initial modulation signal v of phase a ta With positive carrier Size; If the initial modulation signal of phase a is v ta Greater than or equal to positive carrier Then assign 1 to the first intermediate signal S of phase a. a1x If the initial modulation signal of phase a is v ta Less than positive carrier Then assign 0 to the first intermediate signal S of phase a. a1x For the first intermediate signal S of phase a a1x Inverting the signal yields the third intermediate signal S of phase a. a3x ; Compare the initial modulation signal v of phase a ta With load wave Size; If the initial modulation signal of phase a is v ta Greater than or equal to load wave Then assign 1 to the second intermediate signal S of phase a. a2x If the initial modulation signal of phase a is v ta Less than load wave Then assign 0 to the second intermediate signal S of phase a. a2x For the second intermediate signal S of phase a a2x Inverting the signal yields the fourth intermediate signal S of phase a. a4x ; Determine the current I in phase a of the power grid a Is it greater than 0? If the grid current of phase a is I a If the value is greater than 0, then 0 is assigned to the first driving signal S of phase a in the non-zero-crossing interval. a21 and the second driving signal S of phase a a22 The third intermediate signal S of phase a a3x The value is assigned to the third driving signal S of phase a in the non-zero-crossing interval. a23 The fourth intermediate signal S of phase a a4x The value is assigned to the fourth driving signal S of phase a in the non-zero-crossing interval. a24 If the grid current I in phase a a If the value is less than or equal to 0, then the first intermediate signal S of phase a will be... a1x The first driving signal S of phase a in the non-zero-crossing interval is assigned a value. a21 Assign S to the second intermediate signal of phase a. a2x The second driving signal S of phase a in the non-zero-crossing interval a22 Then, 0 is assigned to the third driving signal S of phase a in the non-zero-crossing interval. a23 and the fourth driving signal S of phase a a24 .

[0056] Specifically, see [link to relevant documentation] Figure 10 Methods for generating the b-phase drive signal in the non-zero-crossing interval include: Compare the initial modulation signal v of phase b tb With positive carrier Size; If the initial modulation signal of phase b is v tb Greater than or equal to positive carrier Then assign 1 to the first intermediate signal S of phase b.b1x If the initial modulation signal of phase b is v tb Less than positive carrier Then assign 0 to the first intermediate signal S of phase b. b1x For the first intermediate signal S of phase b b1x Inverting the signal yields the third intermediate signal S of phase b. b3x ; Compare the initial modulation signal v of phase b tb With load wave Size; If the initial modulation signal of phase b is v tb Greater than or equal to load wave Then assign 1 to the second intermediate signal S of phase b. b2x If the initial modulation signal of phase b is v tb Less than load wave Then assign 0 to the second intermediate signal S of phase b. b2x For phase b, the second intermediate signal S b2x Inverting the signal yields the fourth intermediate signal S of phase b. b4x ; Determine the phase b grid current I b Is it greater than 0? If the phase b grid current I b If the value is greater than 0, then 0 is assigned to the first driving signal S of phase b in the non-zero-crossing interval. b21 and the second driving signal S of phase b b22 The third intermediate signal S of phase b b3x The value is assigned to the b-phase third drive signal S in the non-zero-crossing interval. b23 The fourth intermediate signal S of phase b b4x The value is assigned to the fourth driving signal S of phase b in the non-zero-crossing interval. b24 If the grid current in phase b is I b If it is less than or equal to 0, then the first intermediate signal S of phase b will be... b1x The first driving signal S of phase b, assigned to the non-zero-crossing interval b21 Assign S to the second intermediate signal of phase b. b2x The second drive signal S of phase b in the non-zero-crossing interval b22 Then, assign 0 to the third driving signal S of phase b in the non-zero-crossing interval. b23 and the fourth driving signal S of phase b b24 .

[0057] Specifically, see [link to relevant documentation] Figure 10 Methods for generating c-phase drive signals in non-zero-crossing intervals include: Compare the initial modulation signal v of phase c tc With positive carrier Size; If the initial modulation signal of phase c is vtc Greater than or equal to positive carrier Then assign 1 to the first intermediate signal S of phase c. c1x If the initial modulation signal of phase c is v tc Less than positive carrier Then assign 0 to the first intermediate signal S of phase c. c1x For the first intermediate signal S of phase c c1x Inverting the signal yields the third intermediate signal S of phase c. c3x ; Compare the initial modulation signal v of phase c tc With load wave Size; If the initial modulation signal of phase c is v tc Greater than or equal to load wave Then assign 1 to the second intermediate signal S of phase c. c2x If the initial modulation signal of phase c is v tc Less than load wave Then assign 0 to the second intermediate signal S of phase c. c2x For the second intermediate signal S of phase c c2x Inverting the signal yields the fourth intermediate signal S of phase c. c4x ; Determine the c-phase grid current I c Is it greater than 0? If the c-phase grid current I c If the value is greater than 0, then 0 is assigned to the first driving signal S of phase c in the non-zero-crossing interval. c21 and the second driving signal S of phase c c22 The third intermediate signal S of phase c c3x The value is assigned to the c-phase third drive signal S in the non-zero-crossing interval. c23 The fourth intermediate signal S of phase c c4x The value is assigned to the fourth driving signal S of phase c in the non-zero-crossing interval. c24 If the c-phase grid current I c If the value is less than or equal to 0, then the first intermediate signal S of phase c will be... c1x The first driving signal S of phase c, assigned to the non-zero-crossing interval c21 The second intermediate signal of phase c is assigned the value S. c2x The second drive signal S of phase c in the non-zero-crossing interval c22 Then, 0 is assigned to the c-phase third driving signal S in the non-zero-crossing interval. c23 and the fourth driving signal S of phase c c24 .

[0058] S9. Drive signal selection step: Based on the magnitude of the absolute value of the three-phase grid current, select and generate the drive signal for the SiC MOSFET power switching device in the air conditioner compressor drive rectifier according to the drive signal in the zero-crossing interval and the drive signal in the non-zero-crossing interval.

[0059] In one embodiment of this application, the method for selecting the drive signal for the SiC MOSFET power switching device in the air conditioner compressor drive rectifier includes: The absolute values ​​of the three-phase grid currents are obtained by performing absolute value calculations. Determine whether the absolute value of the three-phase power grid current is greater than 1; If the absolute value of the three-phase grid current is greater than 1, the drive signal in the zero-crossing interval is selected as the drive signal for the SiC MOSFET power switching device in the air conditioner compressor drive rectifier; if the absolute value of the three-phase grid current is less than or equal to 1, the drive signal in the non-zero-crossing interval is selected as the drive signal for the SiC MOSFET power switching device in the air conditioner compressor drive rectifier.

[0060] In this embodiment, operating condition identification is achieved by comparing the absolute value of the three-phase grid current with a fixed threshold. In the high-current range, an optimized zero-crossing drive signal is used to drive the SiC MOSFET, while in the low-current range, a conventional non-zero-crossing drive signal is used. When the absolute value of the current is greater than 1 (compressor heavy load, high-current operation), a zero-crossing drive signal optimized by range offset and timing is activated. This improves the turn-on and turn-off timing of the SiC MOSFET at the current zero-crossing point, suppresses voltage spikes and current oscillations generated at the zero-crossing point, improves the sinusoidal nature of the grid-side current waveform, suppresses current harmonics, and reduces power device losses. When the absolute value of the current is less than or equal to 1 (light load, low-current operating condition), the drive algorithm is simplified, reducing the controller's computational load. The anti-parallel diode of the SiC MOSFET itself and the additionally added SiC Schottky diode work together, while the SiC MOSFET does not operate. The parallel current path reduces conduction losses and effectively improves rectifier-side harmonics and electromagnetic interference, effectively suppresses dead-zone effects, reduces current distortion, and balances overall system efficiency, device reliability, and control real-time performance.

[0061] Specifically, see Figure 11 The drive signal selection methods for SiC MOSFET power switching devices in phase a bridge arm include: For phase a grid current I a Perform absolute value calculation to obtain the phase a grid current I. a The absolute value; Determine the current I in phase a of the power grid a Is the absolute value greater than 1? If the grid current of phase a is I aIf the absolute value is greater than 1, then the a-phase drive signal S in the zero-crossing interval is selected. a11 S a12 S a13 S a14 The drive signal S for the SiC MOSFET power switch device in the a-phase bridge arm of the air conditioner compressor drive rectifier. a1 S a2 S a3 S a4 ; If the grid current of phase a is I a If the absolute value is less than or equal to 1, then the a-phase drive signal S in the non-zero-crossing interval is selected. a21 S a22 S a23 S a24 The drive signal S for the SiC MOSFET power switch device in the a-phase bridge arm of the air conditioner compressor drive rectifier. a1 S a2 S a3 S a4 .

[0062] Specifically, see [link to relevant documentation] Figure 11 The drive signal selection methods for SiC MOSFET power switching devices in phase b bridge arm include: For phase b grid current I b Perform absolute value calculation to obtain the phase b grid current I. b The absolute value; Determine the phase b grid current I b Is the absolute value greater than 1? If the phase b grid current I b If the absolute value is greater than 1, then the b-phase drive signal S in the zero-crossing interval is selected. b11 S b12 S b13 S b14 The drive signal S for the SiC MOSFET power switch device in the b-phase bridge arm of the air conditioner compressor drive rectifier. b1 S b2 S b3 S b4 ; If the phase b grid current I b If the absolute value is less than or equal to 1, then the b-phase drive signal S in the non-zero-crossing interval is selected. b21 S b22 S b23 S b24 The drive signal S for the SiC MOSFET power switch device in the b-phase bridge arm of the air conditioner compressor drive rectifier. b1 S b2 S b3S b4 .

[0063] Specifically, see [link to relevant documentation] Figure 11 The drive signal selection methods for SiC MOSFET power switching devices in the c-phase bridge arm include: For c-phase grid current I c Perform absolute value calculation to obtain the c-phase grid current I. c The absolute value; Determine the c-phase grid current I c Is the absolute value greater than 1? If the c-phase grid current I c If the absolute value is greater than 1, then the c-phase drive signal S in the zero-crossing interval is selected. c11 S c12 S c13 S c14 The drive signal S for the SiC MOSFET power switch device in the c-phase bridge arm of the rectifier driving the air conditioner compressor. c1 S c2 S c3 S c4 ; If the c-phase grid current I c If the absolute value is less than or equal to 1, then the c-phase drive signal S in the non-zero-crossing interval is selected. c21 S c22 S c23 S c24 The drive signal S for the SiC MOSFET power switch device in the c-phase bridge arm of the rectifier driving the air conditioner compressor. c1 S c2 S c3 S c4 .

[0064] A second aspect of this application provides a SiC device air conditioner compressor drive rectifier control system for implementing the SiC device air conditioner compressor drive rectifier control method described in the first aspect of this application. See also... Figure 12 The control system includes: The grid voltage angle extraction module transforms the three-phase grid voltage into dq-axis grid voltage based on the grid voltage phase angle θ1, and updates the grid voltage phase angle θ1 based on the q-axis grid voltage. The current command generation module generates a DC-side reference voltage. With the actual DC side voltage u dc The difference is used to obtain the d-axis reference current through PI adjustment. ; The current conversion module converts the three-phase grid current into dq-axis grid current based on the grid voltage phase angle θ1. The inner loop control module is based on PI regulation, according to the d-axis reference current. The dq-axis grid current and dq-axis grid voltage generate the dq-axis voltage modulation signal; A three-phase modulated wave generation module, based on the actual DC-side voltage u dc The phase angle θ1 of the grid voltage is used to generate a three-phase modulated wave signal based on the dq-axis voltage modulation signal; The three-phase modulation wave conversion module combines and transforms the three-phase modulation wave signals to generate the initial modulation wave signal. ; The zero-crossing interval modulation module modulates the lower DC bus capacitor voltage u. dc2 Subtract the DC bus capacitor voltage u dc1 Obtain the balanced signal n p Balanced signal n p Add initial modulation wave signal Obtain the three-phase initial wave modulation signal; subtract 4T from the i-phase initial wave modulation signal. u f s Obtain the first modulation wave signal of phase i. The initial modulation wave signal of phase i is added with 4T u f s Obtain the i-phase second modulation wave signal Where i = a, b, c, T u f is the driving pulse interval adjustment coefficient. s The switching frequency; based on the three-phase initial wave modulation signal, the three-phase first modulation wave signal, and the three-phase second modulation wave signal. , positive carrier Load wave The magnitude of the three-phase grid current generates the driving signal for the zero-crossing interval; Non-zero-crossing interval modulation module, based on three-phase initial modulation signal and positive carrier. Load wave The magnitude of the three-phase grid current generates a drive signal in the non-zero-crossing range; The drive signal selection module selects and generates drive signals for the SiC MOSFET power switching devices in the air conditioner compressor drive rectifier based on the magnitude of the absolute value of the three-phase grid current and the drive signals in the zero-crossing interval and the non-zero-crossing interval.

[0065] The control system described in this application adopts a modular hierarchical architecture, establishing a dual-loop decoupled control system with an outer DC voltage loop and an inner dq-axis current loop. It utilizes a unified grid phase angle to complete three-phase voltage and current coordinate transformation, achieving high-precision phase-locked loop and independent active and reactive power control. By generating a balanced signal and superimposing a modulation wave based on the bus capacitor voltage difference, it compensates for voltage imbalance in real time, effectively suppressing bus capacitor voltage division offset. The system distinguishes between current zero-crossing and non-zero-crossing dual modulation channels, generating multiple reference modulation waves through adjustable offset, and combining multiple waveforms and three-phase current joint discrimination intervals. It adaptively switches between two types of drive signals output to the SiC MOSFET based on the grid current amplitude. The control system described in this application exhibits high steady-state control accuracy and rapid dynamic response, suppressing uneven bus voltage division, input current harmonics, and switching electromagnetic interference, avoiding bridge arm shoot-through faults, and fully adapting to the high-frequency operating characteristics of SiC devices. This effectively improves the power quality, operational safety, and overall energy efficiency of the air conditioning compressor rectifier.

[0066] To verify the effectiveness of the SiC device air conditioner compressor drive rectifier control method and system described in this application, simulation verification was performed in MATLAB / Simulink. The upper DC bus capacitor C1 and the lower DC bus capacitor C2 are both 2200μF, and the three-phase grid voltage E... a E b E c 220V, switching frequency f s =20kHz, drive pulse interval adjustment coefficient T u 2×10 -6 The resistance R of the simulated air conditioner inverter and compressor load is set to 37.5Ω. The three-phase filter inductor L... A L B L C The three-phase separation inductor L is 2mH. A1 L A2 L B3 L B2 L C1 L C2 The dead time is 0.01mH. In the simulation model, the rectifier driven by the air conditioner compressor of the SiC device is controlled by both the traditional control method with dead time and the control method and system proposed in this application. The dead time of the traditional control method with dead time is set to 2×10. -6 s. Figure 13 The three-phase current waveforms and total harmonic distortion (THD) of the current using the traditional control method with dead zone are presented. As can be seen from the figure, there is obvious distortion in the current waveform. The THD of the three-phase currents a, b, and c are 1.75%, 1.76%, and 1.71%, respectively. Figure 14The three-phase current waveforms and THD using the method and system of this application are presented. The sinusoidal nature of the three-phase current waveforms is significantly improved, and the THD of the three-phase currents a, b, and c are 1.11%, 1.12%, and 1.11%, respectively. The THD is effectively reduced, verifying the effectiveness of this application.

[0067] The above embodiments are used to explain this application, not to limit it. Any modifications and changes made to this application within the spirit and scope of the claims shall fall within the protection scope of this application.

Claims

1. A control method for a SiC device-driven rectifier compressor, characterized in that, include: Grid voltage angle extraction steps: Based on the grid voltage phase angle θ1, the three-phase grid voltage is transformed into the dq-axis grid voltage, and the grid voltage phase angle θ1 is updated based on the q-axis grid voltage; Current command generation steps: For the DC side reference voltage... With the actual DC side voltage u dc The difference is used to obtain the d-axis reference current through PI adjustment. ; Current transformation steps: Based on the grid voltage phase angle θ1, the three-phase grid current is transformed into the dq-axis grid current; Control inner loop steps: Based on PI regulation, according to the d-axis reference current. The dq-axis grid current and dq-axis grid voltage generate the dq-axis voltage modulation signal; Three-phase modulated wave generation steps: Based on the actual DC side voltage u dc The phase angle θ1 of the grid voltage is used to generate a three-phase modulated wave signal based on the dq-axis voltage modulation signal; Three-phase modulated wave transformation steps: Combine and transform the three-phase modulated wave signals to generate the initial modulated wave signal. ; Zero-crossing interval modulation steps: The lower DC bus capacitor voltage u... dc2 Subtract the DC bus capacitor voltage u dc1 Obtain the balanced signal n p Balanced signal n p Add initial modulation wave signal Obtain the three-phase initial wave modulation signal; subtract 4T from the i-phase initial wave modulation signal. u f s Obtain the first modulation wave signal of phase i. The initial modulation wave signal of phase i is added with 4T u f s Obtain the i-phase second modulation wave signal Where i = a, b, c, T u f is the driving pulse interval adjustment coefficient. s The switching frequency; based on the three-phase initial wave modulation signal, the three-phase first modulation wave signal, and the three-phase second modulation wave signal. , positive carrier Load wave The magnitude of the three-phase grid current generates the driving signal for the zero-crossing interval; Non-zero-crossing interval modulation steps: based on the three-phase initial modulation signal and the positive carrier. Load wave The magnitude of the three-phase grid current generates a drive signal in the non-zero-crossing range; Drive signal selection steps: Based on the magnitude of the absolute value of the three-phase grid current, the drive signal for the SiC MOSFET power switching device in the air conditioner compressor drive rectifier is selected and generated according to the drive signal in the zero-crossing interval and the drive signal in the non-zero-crossing interval.

2. The SiC device air conditioner compressor drive rectifier control method as described in claim 1, characterized in that, In the grid voltage angle extraction step, the method for transforming the three-phase grid voltage into the dq-axis grid voltage includes: Phase a grid voltage E a Subtract the first set coefficient and multiply by the b-phase grid voltage E b Subtract the first set coefficient and multiply by the c-phase grid voltage E c Then, multiply by the second set coefficient to obtain the α-axis grid voltage E. α ; The third set coefficient is multiplied by the phase b grid voltage E. b Subtract the third set coefficient and multiply by the c-phase grid voltage E c Then, multiply by the second set coefficient to obtain the β-axis grid voltage E. β ; α-axis grid voltage E α The product of cosθ1 and the β-axis grid voltage E β Multiplying by sinθ1, we obtain the d-axis grid voltage e in the two-phase coordinate system. d α-axis grid voltage E α Multiply by -sinθ1 and add the β-axis grid voltage E β Multiplying by cosθ1, we obtain the q-axis grid voltage e in the two-phase coordinate system. q ; Based on the q-axis grid voltage e q Methods for updating the grid voltage phase angle θ1 include: Calculate the grid voltage e along the 0 and q axes. q The difference is used to obtain the first voltage difference; The first voltage difference is passed through a transfer function K. PI1 After the first PI controller with value = 0.25 + 0.35 / s performs PI adjustment, the first intermediate value is obtained; Integrating the difference obtained by subtracting the first intermediate value from 100π, we obtain the grid voltage phase angle θ1.

3. The SiC device air conditioner compressor drive rectifier control method as described in claim 1, characterized in that, The methods for transforming three-phase grid current into dq-axis grid current in the current transformation step include: Phase a grid current I a Multiply by sinθ1 by the fourth set coefficient, then add the b-phase grid current I. b Multiply by sin(θ1-2π / 3), then add the c-phase grid current I. c Multiplying by sin(θ1+2π / 3) yields the d-axis grid current i. d ; Phase a grid current I a Multiply by cosθ1 by the fourth constant coefficient, then add the b-phase grid current I. b Multiply by cos(θ1-2π / 3), then add the c-phase grid current I. c Multiplying by cos(θ1+2π / 3) yields the q-axis grid current i. q .

4. The SiC device air conditioner compressor drive rectifier control method as described in claim 1, characterized in that, In the inner loop control process, the methods for generating the dq-axis voltage modulation signal include: Reference current for the d-axis Reduce d-axis grid current i d The difference is used to obtain a second intermediate value through PI adjustment, and the q-axis grid current i is reduced from 0. q The difference is adjusted using PI to obtain the third intermediate value; d-axis grid voltage e d Subtract the second intermediate value, then add the q-axis grid current i. q The product of 314L and 314L yields the d-axis voltage modulation signal. Where L is the inductance; q-axis grid voltage e q Subtract the third intermediate value, then subtract the d-axis grid current i. d The product of 314L and 314L yields the q-axis voltage modulation signal. .

5. The SiC device air conditioner compressor drive rectifier control method as described in claim 1, characterized in that, The methods for generating a three-phase modulated wave signal in the three-phase modulated wave generation step include: d-axis voltage modulation signal Multiply by 2 and divide by the actual DC side voltage u dc The first intermediate voltage modulation signal is obtained. q-axis voltage modulation signal Multiply by 2 and divide by the actual DC side voltage u dc The second intermediate voltage modulation signal is obtained. ; First intermediate voltage modulation signal The product of sinθ1 and the second intermediate voltage modulation signal Multiplying by cosθ1 yields the phase a modulated wave signal. First intermediate voltage modulation signal The product of sin(θ1-2π / 3) and the second intermediate voltage modulation signal Multiplying by cos(θ1-2π / 3) yields the phase b modulated wave signal. First intermediate voltage modulation signal The product of sin(θ1+2π / 3) and the second intermediate voltage modulation signal Multiplying by cos(θ1+2π / 3) yields the c-phase modulated wave signal. .

6. The SiC device air conditioner compressor drive rectifier control method as described in claim 1, characterized in that, In the three-phase modulation wave transformation step, the initial modulation wave signal is generated. The methods include: Combine the three-phase modulated wave signals into a signal. ; Multiply the signal by the fifth set coefficient to obtain the signal. ; The signal is determined by the judgment module. Is it greater than 0? If signal If the value is greater than 0, then the output of the determination module is a signal. ;if signal If the value is less than 0, the output of the judgment module is 1 plus a signal. ; Take the maximum and minimum output values ​​of the judgment module; Add 1 to the minimum output value, subtract the maximum output value, multiply by 1 / 2, and then multiply by the signal. Add them together to obtain the initial modulated wave signal. .

7. The SiC device air conditioner compressor drive rectifier control method as described in claim 1, characterized in that, In the zero-crossing interval adjustment step, the methods for generating the driving signal for the zero-crossing interval include: Compare the first modulation wave signal of phase i. With positive carrier Size; If the first modulation wave signal of phase i Greater than or equal to positive carrier Then assign 1 to the first intermediate signal S of phase i. i1x If the first modulation wave signal of phase i Less than positive carrier Then assign 0 to the first intermediate signal S of phase i. i1x ; Compare the first modulation wave signal of phase i. With load wave Size; If the first modulation wave signal of phase i Greater than or equal to load wave Then assign 1 to the second intermediate signal S of phase i. i2x If the first modulation wave signal of phase i Less than load wave Then assign 0 to the second intermediate signal S of phase i. i2x ; Compare the initial modulation signal v of phase i ti With positive carrier Size; If the initial modulation signal of phase i is v ti Less than positive carrier Then assign 1 to the third intermediate signal S of phase i. i3x Assign 0 to the fifth intermediate signal S of phase i. i1y If the initial modulation signal of phase i is v ti Greater than or equal to positive carrier Then assign 0 to the third intermediate signal S of phase i. i3x Assign 1 to the fifth intermediate signal S of phase i. i1y ; Compare the initial modulation signal v of phase i ti With load wave Size; If the initial modulation signal of phase i is v ti Less than load wave Then assign 1 to the fourth intermediate signal S of phase i. i4x Assign 0 to the sixth intermediate signal S of phase i. i2y If the initial modulation signal of phase i is v ti Greater than or equal to load wave Then assign 0 to the fourth intermediate signal S of phase i. i4x Assign 1 to the sixth intermediate signal S of phase i. i2y ; Compare the second modulation wave signal of phase i. With positive carrier Size; If the second modulation wave signal of phase i Less than positive carrier Then assign 1 to the seventh intermediate signal S of phase i. i3y If the second modulation wave signal of phase i Greater than or equal to positive carrier Then assign 0 to the seventh intermediate signal S of phase i. i3y ; Compare the second modulation wave signal of phase i. With load wave Size; If the second modulation wave signal of phase i Less than load wave Then assign 1 to the eighth intermediate signal S of phase i. i4y If the second modulation wave signal of phase i Greater than or equal to load wave Then assign 0 to the eighth intermediate signal S of phase i. i4y ; Determine the i-phase grid current I i Is it greater than 0? If the i-phase grid current I i If the value is greater than 0, then the first intermediate signal S of phase i will be... i1x The value is assigned to the first driving signal S of phase i in the zero-crossing interval. i11 Assign S to the second intermediate signal of phase i. i2x The i-phase second drive signal S passing through the zero-point interval is given. i12 The third intermediate signal S of phase i i3x The value is assigned to the i-phase third driving signal S in the zero-crossing interval. i13 The fourth intermediate signal S of phase i i4x The value is assigned to the i-phase fourth driving signal S in the zero-crossing interval. i14 If the i-phase grid current I i If the value is less than or equal to 0, then the fifth intermediate signal S of phase i will be... i1y The value is assigned to the first driving signal S of phase i in the zero-crossing interval. i11 Assign the sixth intermediate signal of phase i to S i2y The i-phase second drive signal S passing through the zero-point interval is given. i12 The seventh intermediate signal S of phase i i3y The value is assigned to the i-phase third driving signal S in the zero-crossing interval. i13 The eighth intermediate signal S of phase i i4y The value is assigned to the i-phase fourth driving signal S in the zero-crossing interval. i14 .

8. The SiC device air conditioner compressor drive rectifier control method as described in claim 1, characterized in that, In the non-zero-crossing interval modulation step, the methods for generating the driving signal for the non-zero-crossing interval include: Compare the initial modulation signal v of phase i ti With positive carrier Size; If the initial modulation signal of phase i is v ti Greater than or equal to positive carrier Then assign 1 to the first intermediate signal S of phase i. i1x If the initial modulation signal of phase i is v ti Less than positive carrier Then assign 0 to the first intermediate signal S of phase i. i1x For the first intermediate signal S of phase i i1x Inverting the signal yields the third intermediate signal S of phase i. i3x ; Compare the initial modulation signal v of phase i ti With load wave Size; If the initial modulation signal of phase i is v ti Greater than or equal to load wave Then assign 1 to the second intermediate signal S of phase i. i2x If the initial modulation signal of phase i is v ti Less than load wave Then assign 0 to the second intermediate signal S of phase i. i2x For the second intermediate signal S of phase i i2x Inverting the signal yields the fourth intermediate signal S of phase i. i4x ; Determine the i-phase grid current I i Is it greater than 0? If the i-phase grid current I i If the value is greater than 0, then 0 is assigned to the first driving signal S of phase i in the non-zero-crossing interval. i21 and i-phase second drive signal S i22 The third intermediate signal S of phase i i3x The value is assigned to the i-phase third driving signal S in the non-zero-crossing interval. i23 The fourth intermediate signal S of phase i i4x The value is assigned to the fourth driving signal S of phase i in the non-zero-crossing interval. i24 If the i-phase grid current I i If the value is less than or equal to 0, then the first intermediate signal S of phase i will be... i1x The first driving signal S of phase i, assigned to the non-zero-crossing interval i21 Assign S to the second intermediate signal of phase i. i2x The second driving signal S of phase i in the non-zero-crossing interval i22 Then, assign 0 to the i-phase third driving signal S in the non-zero-crossing interval. i23 and the fourth driving signal S of phase i i24 .

9. The SiC device air conditioner compressor drive rectifier control method as described in claim 1, characterized in that, In the drive signal selection step, the method for selecting the drive signal for generating the SiC MOSFET power switching device in the air conditioner compressor drive rectifier includes: The absolute values ​​of the three-phase grid currents are obtained by performing absolute value calculations. Determine whether the absolute value of the three-phase power grid current is greater than 1; If the absolute value of the three-phase grid current is greater than 1, then the drive signal in the zero-crossing interval is selected as the drive signal of the SiC MOSFET power switching device in the air conditioner compressor drive rectifier. If the absolute value of the three-phase grid current is less than or equal to 1, then the drive signal in the non-zero-crossing interval is selected as the drive signal for the SiC MOSFET power switching device in the air conditioner compressor drive rectifier.

10. A SiC device air conditioner compressor drive rectifier control system, used to implement the SiC device air conditioner compressor drive rectifier control method as described in any one of claims 1 to 9, characterized in that, include: The grid voltage angle extraction module transforms the three-phase grid voltage into dq-axis grid voltage based on the grid voltage phase angle θ1, and updates the grid voltage phase angle θ1 based on the q-axis grid voltage. The current command generation module generates a DC-side reference voltage. With the actual DC side voltage u dc The difference is used to obtain the d-axis reference current through PI adjustment. ; The current conversion module converts the three-phase grid current into dq-axis grid current based on the grid voltage phase angle θ1. The inner loop control module is based on PI regulation, according to the d-axis reference current. The dq-axis grid current and dq-axis grid voltage generate the dq-axis voltage modulation signal; A three-phase modulated wave generation module, based on the actual DC-side voltage u dc The phase angle θ1 of the grid voltage is used to generate a three-phase modulated wave signal based on the dq-axis voltage modulation signal; The three-phase modulation wave conversion module combines and transforms the three-phase modulation wave signals to generate the initial modulation wave signal. ; The zero-crossing interval modulation module modulates the lower DC bus capacitor voltage u. dc2 Subtract the DC bus capacitor voltage u dc1 Obtain the balanced signal n p Balanced signal n p Add initial modulation wave signal Obtain the three-phase initial wave modulation signal; subtract 4T from the i-phase initial wave modulation signal. u f s Obtain the first modulation wave signal of phase i. The initial modulation wave signal of phase i is added with 4T u f s Obtain the i-phase second modulation wave signal Where i = a, b, c, T u f is the driving pulse interval adjustment coefficient. s The switching frequency; based on the three-phase initial wave modulation signal, the three-phase first modulation wave signal, and the three-phase second modulation wave signal. , positive carrier Load wave The magnitude of the three-phase grid current generates the driving signal for the zero-crossing interval; Non-zero-crossing interval modulation module, based on three-phase initial modulation signal and positive carrier. Load wave The magnitude of the three-phase grid current generates a drive signal in the non-zero-crossing range; The drive signal selection module selects and generates drive signals for the SiC MOSFET power switching devices in the air conditioner compressor drive rectifier based on the magnitude of the absolute value of the three-phase grid current and the drive signals in the zero-crossing interval and the non-zero-crossing interval.

Images