A voltage-type SVM-type decoupled space vector hybrid modulation method

Abstract

The present invention discloses a voltage-type SVM type decoupling space vector hybrid modulation method, which belongs to the technical field of power electronic power converter modulation control. The modulation method is proposed for a voltage-type half-bridge direct matrix converter whose circuit topology includes an input power supply, an input filter, a bidirectional switch group and a three-phase load. The hybrid modulation method is to obtain 6 voltage-type SVM modulation signals through a voltage-type SVM modulation method, and then use them for two purposes: one for modulation control of the matrix converter and the other for coupling logic signal V p 、V n Finally, these two modulation signals, generated by the voltage-type SVM, are subjected to voltage-type coupling logic operations to generate drive signals for each switch tube. This invention decouples the matrix converter into two sets of common rectifiers operating in a common bridge arm, simplifying and facilitating control, reducing control difficulty, improving load adaptability, and facilitating bidirectional energy flow.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronic power converter modulation control, in particular to a voltage-type SVM-type decoupling space vector hybrid modulation method. Background Art

[0002] A converter is a topological device that converts AC power of a certain amplitude and frequency into power of a different amplitude and frequency. Matrix converters are known as "universal converters" and can theoretically directly achieve the same or different input and output phases. Matrix converters, which input three-phase voltage and output three-phase voltage, are particularly common. The topology used in voltage-type half-bridge direct matrix converters is also known as three-phase-to-three-phase matrix converters. These converters can directly convert a three-phase input of a certain amplitude and frequency into a three-phase output of a different amplitude and frequency, theoretically capable of outputting any voltage waveform.

[0003] However, the AC-AC matrix converter has a large number of switches, and the bidirectional switches are connected back-to-back. Therefore, most modulation strategies are difficult to implement and the commutation strategies are complex, resulting in the difficulty in converting the input three-phase voltage into the output three-phase voltage. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a voltage-type SVM-type decoupled space vector hybrid modulation method, so that the matrix converter is decoupled and equivalent to two groups of ordinary rectifiers with common bridge arms to work, the control is simpler and more flexible, and the conversion form of input three-phase voltage to output three-phase voltage is realized, which reduces the control difficulty of the matrix converter, improves the adaptability to the load, and facilitates the bidirectional flow of energy.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A voltage-type SVM type decoupling space vector hybrid modulation method is proposed for a voltage-type half-bridge direct matrix converter whose circuit topology includes an input power supply, an input filter, a bidirectional switch group and a three-phase load. The method is characterized in that six voltage-type SVM modulation signals are obtained by the voltage-type SVM modulation method, and then used for two purposes: one for modulation control of the matrix converter and the other for coupling logic signal V p 、V n Finally, these two signals generated by the voltage-type SVM are operated through voltage-type coupling logic to generate driving signals for each switch tube.

[0007] A further improvement of the technical solution of the present invention is that the circuit topology of the voltage-type half-bridge direct matrix converter is specifically:

[0008] The input power supply adopts a three-phase power supply, the load adopts a star-type three-phase load connection form, the input filter is a three-phase L-type structure, and the bidirectional switch group is a matrix switch group, which is composed of 9 pairs of bidirectional switch tubes;

[0009] The input power is three-phase grid voltage e a 、e b 、e c , three-phase grid voltage e a 、e b 、e c Use star connection; input filter is composed of L a 、L b and L c Composition; three-phase grid voltage e a 、e b 、e c Respectively and L a 、L b and L c One end of the connection;

[0010] The matrix switch group consists of S pahA and S nalA , back-to-back connection S pbhA and S nblA , back-to-back connection S pchA and S nclA ; Back-to-back connection S pahB and S nalB , back-to-back connection S pbhB and S nblB , back-to-back connection S pchB and S nclB ; Back-to-back connection S pahC and S nalC , back-to-back connection S pbhC and S nblC , back-to-back connection S pchC and S nclC These 9 pairs of bidirectional switch tubes constitute;

[0011] Inductor L a The output end and the switch tube S nalA 、S nalB and S nalC The drain connection of the inductor L b The output end and the switch tube S nblA 、S nblB and S nblC The drain connection, inductor L c The output end and the switch tube S nclA 、S nclB and S nclC The drain of is connected;

[0012] The three-phase load resistors include R1, R2 and R3, which are connected in star configuration.

[0013] Switch tube S pahA 、S pbhA and S pchA The drain of the switch is connected to one end of the load R1. pahB 、S pbhB and S pchB The drain of the switch is connected to one end of the load R2. pahC 、S pbhC and S pchC The drain of the load 1 is connected to one end of the load R3, and the other ends of the loads R1, R2 and R3 are connected to each other.

[0014] A further improvement of the technical solution of the present invention is that the modulation method specifically includes the following steps:

[0015] Step 1, obtaining six voltage-type SVM modulation signals SVM1 to SVM6 by an SVM modulation method;

[0016] Step 2: Use the obtained 6-channel voltage-type SVM modulation signals for two purposes:

[0017] A modulation control for a matrix converter;

[0018] The other is used for generating three pairs of polarity selection signals H and L;

[0019] Step 3: Perform a combinational logic operation on the basic modulation signals SVM1 to SVM6 and the polarity selection signals H and L to finally obtain the driving signals of 18 unidirectional switch tubes.

[0020] The further improvement of the technical solution of the present invention is that: in step 1, the input three-phase voltage space is divided into 6 S-shaped voltage regions with reference to two adjacent natural switching points of the input three-phase voltage; in the two-phase stationary coordinate system, the voltage space is divided into 6 sectors by 8 basic spatial voltage vectors; the voltage vector in each sector is synthesized by the two basic effective vectors and the zero vector of the sector; the 6-sector voltage-type SVM modulation finally obtains 6 SVM signals through sector division, sector judgment, vector action time calculation, and vector synthesis sequence selection, and the 3 SVM signals that drive the upper bridge arm of each phase bridge arm are taken and recorded as SVM + , the three SVM signals of each phase lower bridge arm are denoted as SVM - .

[0021] A further improvement of the technical solution of the present invention is that: in step 2, 6-channel voltage-type SVM modulation signals are used to generate 3 pairs of polarity selection signals H and L. The 6-channel SVM drive signals obtained by voltage-type SVM modulation are generated by comparing the saddle-shaped modulation wave with a three-phase phase difference of 120° with the sawtooth carrier to generate 3 pairs of complementary drive signals. When the saddle-shaped modulation wave is greater than the sawtooth carrier, the positive polarity selection signal H is logic "1" and the negative polarity selection signal L is logic "0"; when the saddle-shaped modulation wave is less than the sawtooth carrier, the positive polarity selection signal H is logic "0" and the negative polarity selection signal is logic "1"; three pairs of polarity selection signals H and L with a phase difference of 120° are obtained.

[0022] A further improvement of the technical solution of the present invention is that: the three pairs of polarity selection signals H and L with a phase difference of 120° obtained in step 2 are combined with the six SVM modulation signals obtained in step 1 for logical operation, and the SVM + Perform "OR" combination logic operation with three positive polarity selection signals H to obtain 9 drive signals, including S pahA 、S pbhA 、S pchA 、S pahB 、S pbhB 、S pchB 、S pahC 、S pbhC 、S pchC , SVM - Perform "OR" combination logic operation with three negative polarity selection signals L to obtain 9-way SVM - Drive signals, including S nalA 、S nblA 、S nclA 、S nalB 、S nblB 、S nclB 、S nalC 、S nblC 、S nclC .

[0023] The further improvement of the technical solution of the present invention is that: through the polarity selection logic operation, the bidirectional switch tube is logically decomposed into a unidirectional controllable switch tube, and each of the three groups of the matrix switch group is logically decomposed into two groups of ordinary three-phase half-bridge circuits that output positive voltage and negative voltage; the matrix switch group is logically decomposed to obtain the S pahA 、S pbhA 、S pchA The positive three-phase half bridge of group A is formed; the S pahB 、S pbhB 、S pchB The positive three-phase half bridge of group B is formed; the S pahC 、S pbhC 、S pchCThe positive three-phase half bridge of group C is formed; the S nalA 、S nblA 、S nclA The A group negative group three-phase half bridge is formed; the S nalB 、S nblB 、S nclB The negative group three-phase half bridge of group B is formed; the S nalC 、S nblC 、S nclCc The C group negative group three-phase half bridge is composed of; each group contains the input power supply of the three-phase grid voltage e a 、e b 、e c , the input three-phase L-type filter is L a 、L b 、L c And three-phase star load R1, R2, R3.

[0024] A further improvement of the technical solution of the present invention is that: when the positive three-phase half-bridge circuit of each group of the voltage-type half-bridge direct matrix converter is operating, the positive polarity selection signal H in the three pairs of complementary signals is at a high level, and the negative polarity selection signal L is at a low level; when the negative three-phase half-bridge circuit of each group of the voltage-type half-bridge direct matrix converter is operating, all the switching tubes of the positive three-phase half-bridge are turned on, the positive polarity selection signal H in the three pairs of complementary signals is at a low level, and the negative polarity selection signal L is at a high level.

[0025] Due to the adoption of the above technical solution, the technical advancements achieved by the present invention are:

[0026] 1. The present invention decouples the matrix converter and converts it into two sets of common rectifiers with common bridge arms, making the control simpler and more flexible. It realizes the conversion from input three-phase voltage to output three-phase voltage, reduces the control difficulty of the matrix converter, improves the adaptability to the load, and facilitates the bidirectional flow of energy.

[0027] 2. The input three-phase filter and the bidirectional switch tube group of the present invention are the main energy conversion structures, which are simple, practical and structurally stable.

[0028] 3. When the positive three-phase half-bridge circuit of each group of the voltage-type half-bridge direct matrix converter of the present invention is in operation, the switch tubes of the negative three-phase half-bridge are all turned on, that is, the positive polarity selection signal H in the three pairs of complementary signals is at a high level, and the negative polarity selection signal L is at a low level; when the negative three-phase half-bridge circuit of each group of the voltage-type half-bridge direct matrix converter is in operation, the switch tubes of the positive three-phase half-bridge are all turned on, that is, the positive polarity selection signal H in the three pairs of complementary signals is at a low level, and the negative polarity selection signal L is at a high level. In a 3-way SVM + Signal, 3-way SVM -Under the joint action of the three positive polarity selection signals H with a phase difference of 120°, and the three negative polarity selection signals L with a phase difference of 120°, each group works in coordination, thereby a voltage-type half-bridge direct matrix converter realizes input three-phase output three-phase conversion. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The circuit topology of the voltage-type half-bridge direct matrix converter of the present invention is divided into three groups: A, B, and C;

[0030] Figure 2 This is a block diagram of the system control principle of the present invention;

[0031] Figure 3 It is a partition diagram of the voltage-type SVM type decoupling space vector hybrid modulation strategy in the present invention;

[0032] Figure 4 A distribution diagram of basic vectors and zero vectors of a voltage-type 6-sector SVM modulation method for a voltage-type half-bridge direct matrix converter in the present invention;

[0033] Figure 5 This is a logic decomposition principle diagram of three groups A, B, and C of a voltage-type half-bridge direct matrix converter in the present invention;

[0034] Figure 6 Schematic diagram of the generation principle of three pairs of polarity selection signals H and L with a phase difference of 120° between each other in the present invention;

[0035] Figure 7 A logic processing circuit diagram of a voltage-type SVM-type decoupled space vector hybrid modulation strategy combined logic modulation method in the present invention;

[0036] Figure 8 This is a driving signal principle diagram of a voltage-type SVM decoupling space vector hybrid modulation method in the present invention. DETAILED DESCRIPTION

[0037] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments:

[0038] A voltage-source half-bridge direct matrix converter uses a topology often referred to as a three-phase-three-phase matrix converter. Based on this converter topology, the present invention proposes a voltage-source SVM-type decoupled space vector hybrid modulation method. Positive and negative polarity selection signals logically decompose the matrix converter's bidirectionally controllable switches into unidirectionally controllable switches. A voltage-source six-sector SVM serves as the basic modulation signal for the switches. The six voltage-source SVM modulation signals and three pairs of complementary voltage polarity selection signals are combined for logical processing to generate 18 switch drive signals.

[0039] like Figure 1As shown, a voltage-type half-bridge direct matrix converter has a circuit topology consisting of an input three-phase power supply, an input filter, a matrix switch group for realizing energy conversion, and a three-phase star-type load connected in sequence. The matrix switch group is a bidirectional switch group.

[0040] Three-phase grid voltage e a 、e b 、e c Use star connection; input filter is composed of L a 、L b and L c Composition; three-phase grid voltage e a 、e b 、e c Respectively and L a 、L b and L c One end of the input filter is connected; the input filter is connected by L a 、L b and L c The other ends are respectively connected to the matrix switch group.

[0041] The matrix switch group consists of S pahA and S nalA , back-to-back connection S pbhA and S nblA , back-to-back connection S pchA and S nclA ; Back-to-back connection S pahB and S nalB , back-to-back connection S pbhB and S nblB , back-to-back connection S pchB and S nclB ; Back-to-back connection S pahC and S nalC , back-to-back connection S pbhC and S nblC , back-to-back connection S pchC and S nclC These 9 pairs of bidirectional switch tubes constitute the inductor L a The output end and the switch tube S nalA 、S nalB and S nalC The drain connection of the inductor L b The output end and the switch tube S nblA 、S nblB and S nblC The drain connection, inductor L c The output end and the switch tube S nclA 、S nclB and S nclC The drain of is connected;

[0042] The three-phase load resistors R1, R2 and R3 are connected in star configuration.

[0043] Switch tube S pahA 、S pbhA and S pchA The drain of the switch is connected to one end of the load R1. pahB 、S pbhB and S pchB The drain of the switch is connected to one end of the load R2. pahC 、S pbhC and S pchC The drain of the load 1 is connected to one end of the load R3, and the other ends of the loads R1, R2 and R3 are connected to each other.

[0044] like Figure 2 As shown in the figure, a voltage-type SVM decoupled space vector hybrid modulation method is proposed. The first part is the generation of 6-way SVM modulation signals and 3 pairs of polarity selection signals H and L. Both signals are derived from the modulation signals obtained by 6-sector voltage-type SVM modulation. The 6-sector voltage-type SVM modulation obtains 6-sector voltage-type SVM modulation signals through sector division, sector judgment, vector action time selection, vector synthesis sequence selection, etc., including 3-way SVM signals of each phase upper bridge arm (denoted as SVM + ), 3-way SVM signal of each phase lower bridge arm (denoted as SVM - The second part is the combinational logic part. Take the 3-way signal SVM of each phase upper bridge arm + The third part is the 18-way switch drive signal obtained by performing a combinational logic operation on the 6-way SVM basic modulation signal and the 3 pairs of polarity selection signals H and L.

[0045] like Figure 3 As shown in FIG. 1 , six voltage S-shaped spatial regions are divided by two adjacent natural commutation points in each cycle of the reference voltage signal, that is, six-sector voltage vector divisions.

[0046] like Figure 4 Figure 1 shows the distribution of the six voltage sectors, six basic voltage space vectors, and two zero vectors in a two-phase stationary coordinate system. The voltage vector in each sector is composed of the two effective vectors and the zero vector in that region.

[0047] According to the polarity selection logic operation, the circuit topology of the voltage-type half-bridge direct matrix converter logic decomposition is obtained as follows Figure 5 As shown, each group consists of a positive three-phase half-bridge circuit and a negative three-phase half-bridge circuit, and the logic decomposition principle of each group is the same.

[0048] like Figure 6 The figure shows the principle for generating three pairs of polarity selection signals (H and L) with a 120° phase difference. Polarity selection signals H2 and L2 lead polarity selection signals H1 and L1 by 120°, and polarity selection signals H2 and L2 lag polarity selection signals H3 and L3 by 120°. The six SVM drive signals generated by voltage-type SVM modulation are generated by comparing a saddle-shaped modulation wave with a 120° phase difference with a sawtooth carrier to generate three pairs of complementary drive signals. When the saddle-shaped modulation wave is greater than the sawtooth carrier, the positive polarity selection signals H = 1 and L = 0; when the saddle-shaped modulation wave is less than the sawtooth carrier, H = 0 and L = 1. This generates three pairs of positive and negative polarity selection signals (H and L).

[0049] Three-way SVM + , three-way SVM - Respectively with 3 negative polarity selection signals L and 3 positive polarity selection signals H Figure 7 The "OR" combination logic operation is processed to obtain the driving signal of the matrix switch group. L1, H1 and SVM + , SVM - Perform "OR" combination logic operation to obtain the driving signal of the switch tube of group A; L2, H2 and SVM + , SVM - Perform "OR" combination logic operation to obtain the driving signal of the switch tube of group B; L3 and H3 are respectively connected to SVM + , SVM - Perform an "OR" combination logic operation to obtain the driving signal of the switch tube of group C.

[0050] like Figure 8 The figure shows the principle of synthesizing the driving signals of each switch tube. a+ , SVM b+ , SVM c+ It is the SVM signal of the upper bridge arm of each phase of the three-way bridge arm, and performs an "OR" combination logic operation with the negative polarity selection signal L; SVM a- , SVM b- , SVM c- The SVM signal of each phase's lower bridge arm performs an OR combination logic operation with the positive polarity selection signal H. The three groups of combination logic principles are the same, and only the polarity selection signals are different.

[0051] like Figure 8 As shown, taking one carrier cycle as an example, t 0~ t 1-stage one-way switch tube S pahA 、S pbhA 、S pchA 、S pahB 、S pbhB 、S pchB 、S pahC 、SpbhC 、S pchC 、S nalA 、S nblA 、S nclA 、S nalB 、S nblB 、S nclB 、S nalC 、S nblC 、S nclC In the on state; t 1~ t 2-stage one-way switch tube S pahA 、S pbhA 、S pahB 、S pbhB 、S pahC 、S pbhC 、S pchC 、S nalA 、S nblA 、S nclA 、S nalB 、S nblB 、S nclB 、S nclC In the on state, the unidirectional switch tube S pchA 、S pchB 、S nalC 、S nblC In the off state; t 2~ t 3-stage one-way switch tube S pahA 、S pahB 、S pbhB 、S pchB 、S pahC 、S pbhC 、S pchC 、S nalA 、S nblA 、S nclA 、S nblB 、S nclB 、S nblC 、S nclC In the on state, the unidirectional switch tube S pbhA 、S pchA 、S nalB 、S nalC In the off state; t 3~ t 4-stage one-way switch tube S pahA 、S pbhA 、S pchA 、S pahB 、S pbhB 、S pchB 、S pahC 、S pbhC 、S pchC 、S nalA 、SnblA 、S nclA 、S nalB 、S nblB 、S nclB 、S nalC 、S nblC 、S nclC In the on state.

[0052] The combinational logic portion of the voltage-type SVM decoupled space vector hybrid modulation method described in this invention comprises two parts: logic decomposition and combinational logic operations. First, the logic decomposition analyzes circuit characteristics and physical connections, decomposing bidirectional controllable switches into unidirectional controllable switches. This allows the matrix switch group circuit structure to logically decompose multiple three-phase half-bridge circuits. Second, the combinational logic operations focus on logic transformation and control implementation. The core control principle is to perform combinational logic operations on the six-sector SVM basic modulation signal and the positive and negative polarity selection signals H and L. When the positive three-phase half-bridge is operating, the controllable unidirectional switches of the positive three-phase half-bridge are in a modulation state, while the controllable unidirectional switches of the negative three-phase half-bridge are in an on state. When the negative three-phase half-bridge is operating, the controllable unidirectional switches of the negative three-phase half-bridge are in a modulation state, while the controllable unidirectional switches of the positive three-phase half-bridge are in an on state.

[0053] When the positive three-phase half-bridge circuits of each group of a voltage-type half-bridge direct matrix converter are working, all the switches of the negative three-phase half-bridge are turned on, that is, the positive polarity selection signal H in the three pairs of complementary signals is at a high level, and the negative polarity selection signal L is at a low level; When the negative three-phase half-bridge circuits of each group of a voltage-type half-bridge direct matrix converter are working, all the switches of the positive three-phase half-bridge are turned on, that is, the positive polarity selection signal H in the three pairs of complementary signals is at a low level, and the negative polarity selection signal L is at a high level. Due to the phase difference between the polarity selection signals H and L, the positive and negative three-phase half-bridges of each group and the positive and negative three-phase half-bridge groups of the other two groups can work in coordination. In a 3-way SVM + Signal, 3-way SVM - Under the joint action of the three H signals with a phase difference of 120°, and the three L signals with a phase difference of 120°, a voltage-type half-bridge direct matrix converter can be decoupled into two groups of ordinary rectifiers with common bridge arms to operate, reducing the control difficulty and realizing input three-phase output three-phase energy conversion.

[0054] The embodiments described above are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A voltage-source SVM-type decoupled space vector hybrid modulation method is proposed for a voltage-source half-bridge direct matrix converter whose circuit topology includes an input power supply, an input filter, a bidirectional switch group, and a three-phase load, and is characterized by: The 6-way voltage-type SVM modulation signal is obtained by the voltage-type SVM modulation method, and then used for two purposes: one is used for the modulation control of the matrix converter, and the other is used for coupling the logic signal V p 、V n Finally, the two signals generated by the voltage-type SVM are operated through voltage-type coupling logic to generate the driving signals of each switch tube; The voltage-type coupling logic operation includes: logically decomposing bidirectional switch tubes into unidirectional controllable switch tubes through polarity selection logic operation, so that when the positive group three-phase half-bridge circuit of each group of matrix converters operates, the positive polarity selection signal H in the three pairs of complementary signals is high and the negative polarity selection signal L is low; when the negative group three-phase half-bridge circuit operates, the positive polarity selection signal H is low and the negative polarity selection signal L is high; The specific steps include: Step 1, obtaining six voltage-type SVM modulation signals SVM1 to SVM6 by an SVM modulation method; Step 2: Use the obtained 6-channel voltage-type SVM modulation signals for two purposes: A modulation control for a matrix converter; The other is used for generating three pairs of polarity selection signals H and L; Step 3: Perform a combinational logic operation on the basic modulation signals SVM1 to SVM6 and the polarity selection signals H and L to ultimately obtain the driving signals for 18 unidirectional switch tubes; Through polarity selection logic operation, the bidirectional switch tube is logically decomposed into a unidirectional controllable switch tube. Each of the three groups of matrix switch groups is logically decomposed into two groups of ordinary three-phase half-bridge circuits with output positive voltage and output negative voltage. The matrix switch group is logically decomposed to obtain the S pahA 、S pbhA 、S pchA The positive three-phase half bridge of group A is formed; the S pahB 、S pbhB 、S pchB The positive three-phase half bridge of group B is formed; the S pahC 、S pbhC 、S pchC The positive three-phase half bridge of group C is formed; the S nalA 、S nblA 、S nclA The A group negative group three-phase half bridge is formed; the S nalB 、S nblB 、S nclB The negative group three-phase half bridge of group B is formed; the S nalC 、S nblC 、S nclCc The C group negative group three-phase half bridge is composed of; each group contains the input power supply of the three-phase grid voltage e a 、e b 、e c , the input three-phase L-type filter is L a 、L b 、L c And three-phase star load R1, R2, R3.

2. The voltage-type SVM decoupling space vector hybrid modulation method according to claim 1, characterized in that: The circuit topology of the voltage-type half-bridge direct matrix converter is specifically as follows: The input power supply adopts a three-phase power supply, the load adopts a star-type three-phase load connection form, the input filter is a three-phase L-type structure, and the bidirectional switch group is a matrix switch group, which is composed of 9 pairs of bidirectional switch tubes; The input power is three-phase grid voltage e a 、e b 、e c , three-phase grid voltage e a 、e b 、e c Use star connection; input filter is composed of L a , L b and L c Composition; three-phase grid voltage e a 、e b 、e c Respectively and L a , L b and L c One end of the connection; The matrix switch group consists of S pahA and S nalA , back-to-back connection S pbhA and S nblA , back-to-back connection S pchA and S nclA ; Back-to-back connection S pahB and S nalB , back-to-back connection S pbhB and S nblB , back-to-back connection S pchB and S nclB ; Back-to-back connection S pahC and S nalC , back-to-back connection S pbhC and S nblC , back-to-back connection S pchC and S nclC These 9 pairs of bidirectional switch tubes constitute; Inductor L a The output end and the switch tube S nalA 、S nalB and S nalC The drain connection of the inductor L b The output end and the switch tube S nblA 、S nblB and S nblC The drain connection, inductor L c The output end and the switch tube S nclA 、S nclB and S nclC The drain of is connected; The three-phase load resistors include R1, R2 and R3, which are connected in star configuration. Switch tube S pahA 、S pbhA and S pchA The drain of the switch is connected to one end of the load R1. pahB 、S pbhB and S pchB The drain of the switch is connected to one end of the load R2. pahC 、S pbhC and S pchC The drain of the load 1 is connected to one end of the load R3, and the other ends of the loads R1, R2 and R3 are connected to each other.

3. The voltage-type SVM decoupling space vector hybrid modulation method according to claim 1, characterized in that: In step 1, the input three-phase voltage space is divided into 6 S-shaped voltage regions with reference to two adjacent natural commutation points of the input three-phase voltage; in the two-phase stationary coordinate system, the voltage space is divided into 6 sectors by 8 basic spatial voltage vectors; the voltage vector in each sector is synthesized by the two basic effective vectors and the zero vector of the sector; the 6-sector voltage-type SVM modulation finally obtains 6 SVM signals through sector division, sector judgment, vector action time calculation, and vector synthesis sequence selection, and the 3 SVM signals that drive the upper bridge arm of each phase bridge arm are taken and recorded as SVM + , the three SVM signals of each phase lower bridge arm are denoted as SVM - .

4. The voltage-type SVM decoupling space vector hybrid modulation method according to claim 1, characterized in that: In step 2, 6 voltage-type SVM modulation signals are used to generate 3 pairs of polarity selection signals H and L. The 6 SVM drive signals obtained by voltage-type SVM modulation are generated by comparing the saddle-shaped modulation wave with a three-phase phase difference of 120° with the sawtooth carrier to generate 3 pairs of complementary drive signals. When the saddle-shaped modulation wave is greater than the sawtooth carrier, the positive polarity selection signal H is logic "1" and the negative polarity selection signal L is logic "0"; when the saddle-shaped modulation wave is less than the sawtooth carrier, the positive polarity selection signal H is logic "0" and the negative polarity selection signal is logic "1"; thus, 3 pairs of polarity selection signals H and L with a phase difference of 120° are obtained.

5. The voltage-type SVM decoupling space vector hybrid modulation method according to claim 1, characterized in that: The three pairs of polarity selection signals H and L with a phase difference of 120° obtained in step 2 are combined with the six SVM modulation signals obtained in step 1 for logical operation. + Perform "OR" combination logic operation with three positive polarity selection signals H to obtain 9 drive signals, including S pahA 、S pbhA 、S pchA 、S pahB 、S pbhB 、S pchB 、S pahC 、S pbhC 、S pchC , SVM - Perform "OR" combination logic operation with three negative polarity selection signals L to obtain 9-way SVM - Drive signals, including S nalA 、S nblA 、S nclA 、S nalB 、S nblB 、S nclB 、S nalC 、S nblC 、S nclC .

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