ANPC type multi-port motor drive control system power distribution method based on double-layer space vector decomposition

Abstract

The invention discloses an ANPC type multi-port motor drive control system power distribution method based on double-layer space vector decomposition, and the method comprises the steps: carrying out the equivalent modeling of the space vector modulation of an ANPC type multi-port inverter into double-layer space vector modulation; a reference voltage vector of a multi-port inverter is decomposed into two independent parts corresponding to reference voltage vectors of a two-level inverter according to control parameters, and a modulation method of vector decomposition is used for the double-layer two-level inverter to obtain the duty ratio of an upper-layer inverter and the duty ratio of a lower-layer inverter. After the switching sequences of the two inverters are obtained, the switching sequence of the multi-port inverter can be constructed by superposing the switching sequences of the two two-level inverters, due to the fact that the two two-level inverters are equivalently modeled, decoupling control over port power is achieved, and flexible power distribution can be achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of motor drive control, and more specifically, relates to a power distribution method for an ANPC type multi-port motor drive control system based on double-layer space vector decomposition. Background Art

[0002] Electric vehicles are considered an effective solution to the fossil fuel depletion and environmental challenges posed by internal combustion engines. Among various types of electric vehicles, multi-source electric vehicles (EVs), which combine two or more complementary energy sources for power output, are a leading choice due to their superior range per charge, cost, efficiency, lifespan, and reliability. The power electronics interface, as a key converter in EVs, determines power distribution and motor drive control performance, requiring a well-designed design.

[0003] Compared with other power electronic interface inverter topologies, active-neutral-point-clamped (ANPC) multi-port inverters have many advantages, such as reasonable component utilization, fewer passive components and sufficient control freedom, as well as the ability to operate at the fundamental frequency with some power switching elements. They have become an attractive solution to improve the efficiency and reliability of multi-source electric vehicle systems in industrial or commercial applications.

[0004] Despite these advantages, ANPC-based multi-port inverters are subject to DC link voltage imbalance, resulting in voltage vector asymmetry and a computationally heavy modulation scheme design. Furthermore, compared to ANPC converters, ANPC-based multi-port inverters must achieve ideal power distribution between DC power sources while maintaining efficient motor control. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the existing technology and propose a power distribution control scheme for an ANPC type multi-port motor drive control system based on double-layer space vector decomposition. When the DC port voltage is unbalanced and the low-frequency unit operates at the base frequency, power flow control between DC sources and motor drive control are simultaneously achieved.

[0006] In the proposed scheme, the asymmetric three-level space vector modulation (SVM) is decomposed into symmetrical upper and lower SVM layers, depending on the switching states of the low-frequency unit (LFU). This simplifies the dwell time calculation under unbalanced DC link voltages. Subsequently, a DC port power model is proposed in the upper-layer SVM to achieve the desired power flow control between DC sources. Furthermore, the proposed two-layer SVM ensures fundamental frequency operation of the LFU even under unbalanced DC link voltages.

[0007] To achieve the above-mentioned object of the invention, the present invention provides a power distribution method for an ANPC type multi-port motor drive control system based on double-layer space vector modulation, characterized by comprising the following steps:

[0008] (1) According to the power management strategy of the multi-port motor drive control system, the energy management module gives the reference power P of the upper port u * ;

[0009] (2) Obtain the reference voltage vector v on the multi-port inverter side * ;

[0010] (3) Equivalent modeling and power distribution control of multi-port inverters;

[0011] The multi-port inverter is equivalently modeled as a two-level inverter with two layers, where the DC link voltage of the upper layer inverter is denoted as v H -v L , the DC link voltage of the lower inverter is v L The equivalent switch tube of the upper inverter is denoted as S x1 、S x3 , the equivalent switch tube of the lower inverter is denoted as S x2 、S x4 ;S x1 、S x2 、S x3 、S x4 They respectively represent the first switch tube, the second switch tube, the third switch tube, and the fourth switch tube in the x-th phase bridge arm of the multi-port inverter baseband unit;

[0012] (4) Determine the reference voltage vector v according to the phase angle θ * In the corresponding sector, two adjacent basic voltage vectors and zero vector are selected to synthesize the reference voltage vector v * , then solve for the reference voltage vector v * The reference vector v corresponding to the decomposed upper and lower layers u * and v l * , we can get the three-phase duty cycle d of the upper and lower double-layer inverter xu and d xl ;

[0013] (5) Generate the modulation waveform SVPWM through the duty cycle of each phase of the upper and lower inverters u With SVPWM l Then, the modulation waveform is compared with the amplitude of the triangular carrier in one switching cycle to generate the switching signal G that drives the multi-port inverter. x1 , G x2 , Gx3 ;

[0014] The switch signal G x1 , G x2 Acting on the three bridge arms of the multi-port inverter, using the driving signal G x1 Control switch tube S x1 , driving signal G x1 The complementary signal controls the switch tube S x3 , driving signal G x2 Control switch tube S x2 , driving signal G x2 The complementary signal controls the switch tube S x4 , driving signal G x3 Control switch tube S x5 , driving signal G x3 The complementary signal controls the switch tube S x6 , thereby controlling the switching tubes on each bridge arm to perform switching actions.

[0015] The object of the invention of the present invention is achieved like this:

[0016] The present invention provides a power allocation method for an ANPC-type multi-port motor drive control system based on double-layer space vector decomposition. The space vector modulation of an ANPC-type multi-port inverter is equivalently modeled as double-layer space vector modulation. The reference voltage vector of the multi-port inverter is decomposed into two independent parts corresponding to the reference voltage vector of a two-level inverter according to control parameters. The vector decomposition modulation method is used on the double-layer two-level inverter to obtain the duty cycle of the upper and lower inverters. After obtaining the switching sequences of the two inverters, the switching sequence of the multi-port inverter can be constructed by superimposing the switching sequences of the two two-level inverters. By equivalently modeling two two-level inverters, decoupled control of the port power is achieved, thereby enabling flexible power allocation.

[0017] At the same time, the power allocation method of the ANPC type multi-port motor drive control system based on double-layer space vector decomposition of the present invention also has the following beneficial effects:

[0018] (1) In the present invention, the topology adopts an ANPC type multi-port inverter, which has fewer passive components and sufficient control freedom compared to the traditional NPC type topology, can effectively utilize different types of switching devices, and has the fundamental frequency working capability of some power switching elements.

[0019] (2) According to the switching state of the low-frequency unit, the asymmetric three-level space vector modulation is decomposed into symmetrical upper space vector modulation and lower space vector modulation, which simplifies the calculation of the modulation residence time, reduces the calculation burden of the system, and reduces the switching loss under the condition of DC link voltage imbalance.

[0020] (3) In order to achieve flexible power control under the condition of port voltage imbalance, the present invention proposes a DC port instantaneous power model and corresponding modulation scheme based on upper-layer space vector modulation, which realizes flexible power flow and motor drive control. It can not only avoid the complex modulation problems caused by DC link imbalance, but also realize decoupling control, and the port power can be controlled independently.

[0021] (4) Even in the case of unbalanced DC link voltage, the proposed two-layer space vector modulation scheme can ensure the base frequency operation of the low-frequency unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a diagram of the motor drive system structure based on the ANPC type multi-port inverter connection;

[0023] Figure 2 It is a double-layer space vector equivalent decoupling model of ANPC type multi-port inverter;

[0024] Figure 3 This is a power distribution control block diagram of the ANPC type multi-port motor drive control system based on double-layer space vector decomposition of the present invention;

[0025] Figure 4 The power allocation method of ANPC type multi-port motor drive control system based on double-layer space vector decomposition is used for three different port voltages v H -v L >v L 、v H -v L =v L and v H -v L <v L Steady-state performance of work under conditions;

[0026] Figure 5 It is the power distribution range of the ANPC type multi-port motor drive control system power distribution method based on double-layer space vector decomposition under different port voltage ratios and different modulation coefficients. DETAILED DESCRIPTION

[0027] The following describes the specific embodiments of the present invention in conjunction with the accompanying drawings so that those skilled in the art can better understand the present invention. It should be noted that in the following description, when detailed descriptions of known functions and designs may dilute the main content of the present invention, such descriptions will be omitted here.

[0028] Example

[0029] Figure 1This is the structure diagram of the motor drive system based on the ANPC type multi-port inverter connection.

[0030] In this embodiment, we first analyze the topology of the multi-port motor drive control system based on double-layer space vector decomposition. Figure 1 As shown, it includes: main power supply, auxiliary power supply, ANPC type multi-port inverter, and permanent magnet synchronous motor. Among them, the ANPC type multi-port inverter is an improvement of the ANPC type three-level inverter topology, connecting one power supply at the positive and negative poles and another power supply between the neutral line and the ground line, while retaining the original three bridge arms of the inverter. x1 :S x4 The low-frequency unit that makes up the inverter, S x5 :S x6 The high-frequency unit that makes up the inverter has the following specific structure:

[0031] The ANPC multi-port inverter includes a position encoding module, a speed calculation module, a reference power output module, a power PI modulation module, a multi-port inverter modulation module, a T1 coordinate transformation unit, a speed PI control module, a d-axis PI control module, a q-axis PI control module, a T2 coordinate transformation unit, a first difference operation unit, a second difference operation unit, a third difference operation unit, and a fourth difference operation unit;

[0032] The input end of the position encoding module is connected to the permanent magnet synchronous motor, and its output end is connected to the input end of the speed calculation module, the T1 coordinate transformation unit, and the T2 coordinate transformation unit, so as to calculate the actual speed w of the permanent magnet synchronous motor by the speed calculation module using the position angle θ. e ;

[0033] The output of the speed calculation module is connected to the input of the speed PI control module through the first difference operation unit, which is used to convert the given speed With the actual speed w e The difference is calculated by the first difference operation unit, and then the PI control is performed through the speed controller to obtain the first given current of the q axis

[0034] The output end of the speed PI control module is connected to the input end of the q-axis PI control module through the second difference operation unit, which is used to convert the three-phase current i sampled by the three-phase current detector into a 、i b 、i c The first actual current i of the q axis is obtained through the T1 coordinate transformation unit q , and then with i q The difference is calculated by the second difference operation unit, and the PI control is performed through the q-axis current controller to generate the q-axis first given voltage v of the plane under the rotating coordinate system. q;

[0035] The input end of the d-axis PI control module is connected to the third difference operation unit, which is used to convert the three-phase current i collected by the three-phase current detector into a 、i b 、i c The second actual current i of the d-axis is obtained by T1 coordinate transformation d , the second given current of d axis With the second actual current i d The difference is calculated by the second difference operation unit, and then the PI controller of the d-axis is used for PI control to generate the second given voltage v of the d-axis of the plane in the rotating coordinate system. d ;

[0036] The output terminals of the d-axis PI control module and the q-axis PI control module are connected to the input terminal of the T2 coordinate transformation unit, and the output terminal of the T2 coordinate transformation unit is connected to the multi-port inverter modulation module for converting the first given voltage v q , the second given voltage v d The reference voltage v of the plane in the stationary coordinate system is obtained through the T2 coordinate transformation unit α 、v β ;

[0037] The input end of the multi-port inverter modulation module is connected to the output end of the T2 coordinate transformation unit to convert the reference voltage v α 、v β Generate a corresponding driving signal based on space vector pulse width modulation through a multi-port inverter modulation module and output it to the multi-port inverter;

[0038] A simple frequency divider is used for energy management to divide the load power demand into two parts: low frequency and high frequency. The load demand frequency decoupling is achieved through a high-pass filter, and the high frequency part is fed into a fast acting power supply (auxiliary power supply), denoted as P l * , such as supercapacitors; the rest of the power is fed into the slow-acting power supply (main power supply), denoted as P u * , such as a fuel cell or battery. The output end of the reference power output module is connected to the fourth difference operation unit, which is used to calculate the upper reference output power P of the output multi-port inverter. u * .

[0039] Figure 2 It is a double-layer space vector equivalent decoupling model of ANPC type multi-port inverter.

[0040] In the first sector, according to the switching state of the low-frequency unit, the double-layer space vector equivalent decoupling of the multi-port inverter can be divided into the following categories: Figure 2 The two situations shown are as follows. Figure 2 As shown in (a), when the switching state of the low-frequency unit is S a1 S a2 S a3 =(1 00), the output power of the upper inverter port depends on the output voltage of phase a. Figure 2 As can be seen from (a), the upper space vector decomposition only requires one switching operation, while the lower space vector decomposition requires two. Figure 2 As shown in (b), when the switching state of the low-frequency unit is S a1 S a2 S a3 =(1 1 0), the output power of the upper inverter port depends on the output voltage of phase c. Figure 2 As can be seen in (b), the lower-level space vector decomposition requires only one switching operation, while the upper-level space vector decomposition requires two. Therefore, under the proposed method based on two-level space vector decomposition, the total number of switching operations of the ANPC multi-port inverter is three.

[0041] Similarly, in the second sector, the switching state of the low-frequency unit is divided into S a1 S a2 S a3 =(1 1 0) and S a1 S a2 S a3 =(0 1 0), the third sector is divided into S a1 S a2 S a3 =(0 1 0) and S a1 S a2 S a3 =(0 1 1), the fourth sector is divided into S a1 S a2 S a3 =(0 1 1) and S a1 S a2 S a3 =(0 0 1), the fifth sector is divided into S a1 S a2 S a3 =(0 0 1) and S a1 S a2 S a3 =(1 0 1), the sixth sector is divided into S a1 S a2 S a3 =(1 0 1) and S a1 S a2 S a3 =(1 0 0).

[0042] Figure 3The present invention is a power distribution control block diagram of an ANPC type multi-port motor drive control system based on double-layer space vector decomposition.

[0043] In this embodiment, combined with Figure 3 The power allocation method of the ANPC type multi-port motor drive control system based on double-layer space vector decomposition of the present invention is described in detail, which specifically includes the following steps:

[0044] (1) According to the power management strategy of the multi-port motor drive control system, the energy management module gives the reference power P of the upper port u * ;

[0045] (2) Obtain the reference voltage vector v on the multi-port inverter side * ;

[0046] (2.1), given the three-phase reference voltage v that is expected to be obtained on the load side of the multi-port motor drive control system x * ;

[0047] (2.2), the three-phase reference voltage v x * After T1 coordinate transformation, the reference voltage v of the multi-port inverter in the dq coordinate system is obtained d * 、v q * ;

[0048] The voltage v output by the three-phase voltage detector in the ANPC multi-port motor drive control system x After T1 coordinate transformation, the voltage v of the dq axis is obtained d 、v q ; The current i output by the three-phase current detector x After T1 coordinate transformation, the current i in the dq coordinate system is obtained d 、i q ;

[0049] In this embodiment, the three-phase reference voltage v x * For example, the formula for T1 coordinate transformation is:

[0050]

[0051] where θ is the phase angle, is the reference voltage in the dq coordinate system;

[0052] (2.3), v d * and v dThe difference is then passed through the d-axis voltage PI controller to obtain the d-axis current

[0053] Will and i d The difference is then passed through the d-axis current PI controller to obtain the d-axis voltage Then With v d * Sum and get the final output voltage of the d-axis

[0054] (2.4), v q * and v q The difference is then passed through the q-axis voltage PI controller to obtain the q-axis current

[0055] Will and i q The difference is then passed through the q-axis current PI controller to obtain the q-axis voltage Then With v q * Sum and get the final output voltage of q axis

[0056] (2.5) The final output voltage of the dq axis Through T2 coordinate transformation, the voltage value v of the multi-port inverter in the αβ coordinate system is obtained α * 、v β * ;

[0057] In this embodiment, the formula for T2 coordinate transformation is:

[0058]

[0059] Among them, v α * 、v β * is the voltage value of the multi-port inverter in the αβ coordinate system;

[0060] (2.6), the voltage value v α * 、v β * Through T3 coordinate transformation, the reference voltage vector v on the multi-port inverter side is obtained * ;

[0061] In this embodiment, the formula for T3 coordinate transformation is:

[0062]

[0063] Among them, v * is the reference voltage vector on the multi-port inverter side;

[0064] (3) Equivalent modeling and power distribution control of multi-port inverters;

[0065] (3.1) Equivalent modeling: The multi-port inverter is equivalently modeled as a two-level inverter with two layers, where the DC link voltage of the upper layer inverter is v H -v L , the DC link voltage of the lower inverter is v L The equivalent switch tube of the upper inverter is denoted as S x1 、S x3 , the equivalent switch tube of the lower inverter is denoted as S x2 、S x4 ;S x1 、S x2 、S x3 、S x4 They respectively represent the first switch tube, the second switch tube, the third switch tube, and the fourth switch tube in the x-th phase bridge arm of the multi-port inverter baseband unit;

[0066] (3.2) Power allocation control: In two-level space vector modulation, the space voltage vector can be divided into the following six sectors according to the phase angle θ:

[0067]

[0068] According to the reference voltage vector of the upper inverter v u * , v u * ∈[0,v H -v L ], the reference voltage vector of the lower inverter is v l * , v l * ∈[0,v L ]; Calculate the reference power of the AC side motor as:

[0069]

[0070] The output power reference of the upper inverter is:

[0071]

[0072] in, represents the current i x The conjugate, proportionality coefficient

[0073] The multi-port inverter takes the reference voltage vector v * According to the proportional coefficient λ, it is respectively distributed to the upper and lower inverters. In the first sector, when the low-frequency unit switching state is (1 0 0), the output reference voltage vector of the upper inverter can be expressed as

[0074]

[0075] When the switching state of the low-frequency unit is (1 1 0), the output reference voltage vector of the upper inverter can be expressed as

[0076]

[0077] In other sectors, refer to Figure 2 The switching state of the low-frequency unit in the corresponding sector, the output reference voltage vector expression of the upper and lower double-layer inverter can be obtained similarly. The two adjacent basic voltage vectors change from (V1, V2) to: the second sector (V2, V3), the third sector (V3, V4), the fourth sector (V4, V5), the fifth sector (V5, V6), and the sixth sector (V6, V1).

[0078] (4) Determine the reference voltage vector v according to the phase angle θ * In the corresponding sector, two adjacent basic voltage vectors and zero vector are selected to synthesize the reference voltage vector v * , then solve for the reference voltage vector v * The reference vector v corresponding to the decomposed upper and lower layers u * and v l * , we can get the three-phase duty cycle d of the upper and lower double-layer inverter xu and d xl ;

[0079] (4.1) In the first sector, combining the obtained λ1 and λ2, the calculation process of the reference vector corresponding to the upper inverter is as follows:

[0080]

[0081] in

[0082] Through the above formula, we can get

[0083] t u1 =λ1εt1

[0084] t u2 =λ2εt2

[0085] where tu1 and t u2 Represents V u1 and V u2 residence time.

[0086] The calculation process of the reference vector corresponding to the lower inverter is as follows:

[0087]

[0088] in

[0089] Through the above formula, we can get

[0090]

[0091]

[0092] where t l1 and t l2 Represents V l1 and V l2 residence time.

[0093] In other sectors, the residence time of the upper and lower double-layer adjacent synthetic vectors can be obtained by the same logic. The two adjacent basic voltage vectors change from (V1, V2) to: the second sector (V2, V3), the third sector (V3, V4), the fourth sector (V4, V5), the fifth sector (V5, V6), and the sixth sector (V6, V1).

[0094] Construct an expression for the dwell time between two adjacent non-zero vectors and a zero vector within each sector:

[0095] T S v * =t1v k1 +t2v k2 +t0v k0

[0096] T S =t1+t2+t0

[0097] Among them, T s is the switching period, v k1 、v k2 、v k0 The two adjacent non-zero vectors and the zero vector that make up the k-th sector, k = 1, 2, 3, 4, 5, 6 represent 6 sector numbers; t1, t2, t0 are the dwell times corresponding to each vector;

[0098] (4.2), according to the reference voltage vector v of the upper inverter u * and the reference voltage vector v of the lower inverter l* , respectively determine which sector the phase of each reference voltage vector falls in, and then calculate the residence time corresponding to each vector based on the formula in step S4.1, where the residence time of the upper inverter is recorded as t uz , the residence time of the upper inverter is recorded as t lz , z=0,1,2 represents two adjacent non-zero vectors and a zero vector;

[0099] (4.3) Calculate the duty cycle of each phase of the upper inverter and the lower inverter based on the classic PWM strategy;

[0100]

[0101] Among them, d xu is the duty cycle of each phase of the upper inverter, d xl is the duty cycle of each phase of the lower inverter;

[0102] (5) Generate the modulation waveform SVPWM through the duty cycle of each phase of the upper and lower inverters u With SVPWM l Then, the modulation waveform is compared with the amplitude of the triangular carrier in one switching cycle to generate the switching signal G that drives the multi-port inverter. x1 , G x2 , G x3 ;

[0103] The switch signal G x1 , G x2 Acting on the three bridge arms of the multi-port inverter, using the driving signal G x1 Control switch tube S x1 , driving signal G x1 The complementary signal controls the switch tube S x3 , driving signal G x2 Control switch tube S x2 , driving signal G x2 The complementary signal controls the switch tube S x4 , driving signal G x3 Control switch tube S x5 , driving signal G x3 The complementary signal controls the switch tube S x6 , thereby controlling the switching tubes on each bridge arm to perform switching actions.

[0104] This embodiment is described with reference to examples. Figure 4 As shown, assume that the DC side high voltage v H =300V, low voltage v L =125V / 150V / 175V, observe the situation under different DC port voltages (a), (b), (c) correspond to v H-v L >v L 、v H -v L =v L and v H -v L <v L In this case, the AC side power demand P = 900w. By observing the phase voltage output by the multi-port inverter under variable port voltage, it can be proved that the switching state of the three-level multi-port inverter can be constructed by superimposing the upper inverter and the lower inverter, and the three working states can achieve good tracking performance of the desired grid voltage / current. Although the voltages of the two DC ports are different, the current tracking effect is almost the same, and the ripples of the high-voltage and low-voltage port currents on the DC side are stably controlled to be very small. Figure 5 As shown in the figure, by observing the power distribution results of the scheme proposed by the present invention under different port voltage ratios and different modulation coefficients, it can be concluded that the proposed strategy has a wider power distribution range and realizes a wide range of DC port power distribution output.

[0105] Although the above describes the illustrative specific embodiments of the present invention to facilitate understanding of the present invention by those skilled in the art, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the appended claims, these changes are obvious, and all inventions and creations using the concepts of the present invention are protected.

Claims

1. A power allocation method for an ANPC type multi-port motor drive control system based on double-layer space vector decomposition, characterized in that: The following steps are involved: (1) According to the power management strategy of the ANPC multi-port motor drive control system, the energy management module gives the reference power of the upper port (2) Obtain the reference voltage vector v on the multi-port inverter side * ; (2.1), given the three-phase reference voltage v that is expected to be obtained on the load side of the ANPC multi-port motor drive control system x * , x=a,b,c represents three phases; (2.2), the three-phase reference voltage v x * After T1 coordinate transformation, the reference voltage v of the multi-port inverter in the dq coordinate system is obtained d * 、v q * ; The voltage v output by the three-phase voltage detector in the ANPC multi-port motor drive control system x After T1 coordinate transformation, the voltage v of the dq axis is obtained d 、v q ; The current i output by the three-phase current detector x After T1 coordinate transformation, the current i in the dq coordinate system is obtained d 、i q ; ( 2.3) Set v d * and v d The difference is then passed through the d-axis voltage PI controller to obtain the d-axis current Will and i d The difference is then passed through the d-axis current PI controller to obtain the d-axis voltage Then With v d * Sum and get the final output voltage of the d-axis (2.4), v q * and v q The difference is then passed through the q-axis voltage PI controller to obtain the q-axis current Will and i q The difference is then passed through the q-axis current PI controller to obtain the q-axis voltage Then With v q * Sum and get the final output voltage of q axis (2.5) The final output voltage of the dq axis Through T2 coordinate transformation, the voltage value v of the multi-port inverter in the αβ coordinate system is obtained α * 、v β * ; (2.6), the voltage value v α * 、v β * Through T3 coordinate transformation, the reference voltage vector v on the multi-port inverter side is obtained * ; (3) Equivalent modeling and power distribution control of multi-port inverters; (3.1) Equivalent modeling: The multi-port inverter is equivalently modeled as a two-level inverter with two layers, where the DC link voltage of the upper layer inverter is v H -v L , the DC link voltage of the lower inverter is v L The equivalent switch tube of the upper inverter is denoted as S x1 、S x3 , the equivalent switch tube of the lower inverter is denoted as S x2 、S x4 ;S x1 、S x2 、S x3 、S x4 They respectively represent the first switch tube, the second switch tube, the third switch tube, and the fourth switch tube in the x-th phase bridge arm of the multi-port inverter baseband unit; (3.2) Power distribution control: In two-level space vector modulation, the space voltage vector is divided into the following six sectors according to the phase angle θ: According to the reference voltage vector of the upper inverter v u * , v u * ∈[0,v H -v L ], the reference voltage vector of the lower inverter is v l * , v l * ∈[0,v L ]; Calculate the reference power P of the AC side motor * and the output power reference P of the upper inverter u * for: in, represents the current i x The conjugate, proportionality coefficient The multi-port inverter takes the reference voltage vector v * According to the proportional coefficient λ, it is respectively distributed to the upper and lower inverters. In the first sector, when the low-frequency unit switching state is (1 0 0), the reference voltage vector allocated to the upper inverter is: When the switching state of the low-frequency unit is (1 1 0), the reference voltage vector allocated by the upper inverter is: In other sectors, the reference voltage vectors allocated to the upper and lower double-layer inverters can be obtained similarly. Specifically, the two adjacent basic voltage vectors (V1, V2) are changed to: the second sector (V2, V3), the third sector (V3, V4), the fourth sector (V4, V5), the fifth sector (V5, V6), and the sixth sector (V6, V1). (4) Determine the reference voltage vector v according to the phase angle θ * In the corresponding sector, two adjacent basic voltage vectors and zero vector are selected to synthesize the reference voltage vector v * , then solve for the reference voltage vector v * The reference vector v corresponding to the decomposed upper and lower layers u * and v l * , we can get the three-phase duty cycle d of the upper and lower double-layer inverter xu and d xl ; (5) Generate the modulation waveform SVPWM through the duty cycle of each phase of the upper and lower inverters u With SVPWM l Then, the modulation waveform is compared with the amplitude of the triangular carrier in one switching cycle to generate the switching signal G that drives the multi-port inverter. x1 , G x2 , G x3 ; The switch signal G x1 , G x2 Acting on the three bridge arms of the multi-port inverter, using the driving signal G x1 Control switch tube S x1 , driving signal G x1 The complementary signal controls the switch tube S x3 , driving signal G x2 Control switch tube S x2 , driving signal G x2 The complementary signal controls the switch tube S x4 , driving signal G x3 Control switch tube S x5 , driving signal G x3 The complementary signal controls the switch tube S x6 , thereby controlling the switching tubes on each bridge arm to perform switching actions.

2. The power allocation method of the ANPC type multi-port motor drive control system based on double-layer space vector decomposition according to claim 1 is characterized in that: The formula for the T1 coordinate transformation is: where θ is the phase angle, is the reference voltage in the dq coordinate system.

3. The power allocation method of the ANPC type multi-port motor drive control system based on double-layer space vector decomposition according to claim 1 is characterized in that: The formula for the T2 coordinate transformation is: Among them, v α * 、v β * is the voltage value of the multi-port inverter in the αβ coordinate system.

4. The power allocation method of the ANPC type multi-port motor drive control system based on double-layer space vector decomposition according to claim 1 is characterized in that: The formula for the T3 coordinate transformation is: Among them, v * is the reference voltage vector on the multi-port inverter side.

5. The power allocation method of the ANPC type multi-port motor drive control system based on double-layer space vector decomposition according to claim 1 is characterized in that: The three-phase duty cycle d of the upper and lower double-layer inverter xu and d xl The specific calculation method is: (5.1) In the first sector, combining the obtained λ1 and λ2, the calculation process of the reference vector corresponding to the upper inverter is: in, From the above formula we can get: t u1 =λ1εt1 t u2 =λ2εt2 Among them, t u1 and t u2 Represents V u1 and V u2 residence time; The calculation process of the reference vector corresponding to the lower inverter is: in From the above formula we can get: Among them, t l1 and t l2 Represents V l1 and V l2 residence time; In other sectors, the residence time of the upper and lower double-layer adjacent synthetic vectors can be obtained in the same way. Specifically, the two adjacent basic voltage vectors are changed from (V1, V2) to: the second sector (V2, V3), the third sector (V3, V4), the fourth sector (V4, V5), the fifth sector (V5, V6), and the sixth sector (V6, V1); Construct an expression for the dwell time between two adjacent non-zero vectors and a zero vector within each sector: T S v * =t1v k1 +t2v k2 +t0v k0 T S =t1+t2+t0 Among them, T s is the switching period, v k1 、v k2 、v k0 The two adjacent non-zero vectors and the zero vector that make up the k-th sector, k = 1, 2, 3, 4, 5, 6 represent 6 sector numbers; t1, t2, t0 are the dwell times corresponding to each vector; (5.2), according to the reference voltage vector v of the upper inverter u * and the reference voltage vector v of the lower inverter l * , respectively determine which sector the phase of each reference voltage vector falls in, and then calculate the residence time corresponding to each vector based on the formula in step (5.1), where the residence time of the upper inverter is recorded as t uz , the residence time of the upper inverter is recorded as t lz , z=0,1,2 represents two adjacent non-zero vectors and a zero vector; (5.3) Calculate the duty cycle of each phase of the upper inverter and the lower inverter based on the classic PWM strategy; Among them, d xu is the duty cycle of each phase of the upper inverter, d xl is the duty cycle of each phase of the lower inverter.

6. An ANPC type multi-port motor drive control system based on double-layer space vector decomposition, characterized in that: include: Main power supply, auxiliary power supply, ANPC multi-port inverter, permanent magnet synchronous motor; The ANPC multi-port inverter further includes a position encoding module, a speed calculation module, a reference power output module, a power PI modulation module, a multi-port inverter modulation module, a T1 coordinate transformation unit, a speed PI control module, a d-axis PI control module, a q-axis PI control module, a T2 coordinate transformation unit, a first difference operation unit, a second difference operation unit, a third difference operation unit, and a fourth difference operation unit. The input end of the position encoding module is connected to the permanent magnet synchronous motor, and its output end is connected to the input end of the speed calculation module, the T1 coordinate transformation unit, and the T2 coordinate transformation unit, so as to calculate the actual speed w of the permanent magnet synchronous motor by the speed calculation module using the position angle θ. e ; The output of the speed calculation module is connected to the input of the speed PI control module through the first difference operation unit, which is used to convert the given speed With the actual speed w e The difference is calculated by the first difference operation unit, and then the PI control is performed through the speed controller to obtain the first given current of the q axis The output end of the speed PI control module is connected to the input end of the q-axis PI control module through the second difference operation unit, which is used to convert the three-phase current i sampled by the three-phase current detector into a 、i b 、i c The first actual current i of the q axis is obtained through the T1 coordinate transformation unit q , and then with i q The difference is calculated by the second difference operation unit, and the PI control is performed through the q-axis current controller to generate the q-axis first given voltage v of the plane under the rotating coordinate system. q ; The input end of the d-axis PI control module is connected to the third difference operation unit, which is used to convert the three-phase current i collected by the three-phase current detector into a 、i b 、i c The second actual current i of the d-axis is obtained by T1 coordinate transformation d , the second given current of d axis With the second actual current i d The difference is calculated by the second difference operation unit, and then the PI controller of the d-axis is used for PI control to generate the second given voltage v of the d-axis of the plane in the rotating coordinate system. d ; The output terminals of the d-axis PI control module and the q-axis PI control module are connected to the input terminal of the T2 coordinate transformation unit, and the output terminal of the T2 coordinate transformation unit is connected to the multi-port inverter modulation module for converting the first given voltage v q , the second given voltage v d The reference voltage v of the plane in the stationary coordinate system is obtained through the T2 coordinate transformation unit α 、v β ; The input end of the multi-port inverter modulation module is connected to the output end of the T2 coordinate transformation unit to convert the reference voltage v α 、v β The corresponding driving signal is generated by the multi-port inverter modulation module based on space vector pulse width modulation and output to the multi-port inverter.

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