Harmonic voltage modulation method for five-phase permanent magnet synchronous motor and readable storage medium

Abstract

The present application relates to a kind of five-phase permanent magnet synchronous motor harmonic voltage modulation method and readable storage medium, method includes: the maximum action time of motor control voltage reference vector in clockwise direction and counterclockwise direction adjacent mid-vector in αβ Coordinate system is calculated respectively, determine the corresponding two action time range;Two action time range is equally divided into same several parts to obtain two finite sets, and the corresponding harmonic voltage is calculated based on different value combinations of two finite sets;Select the harmonic voltage closest to harmonic voltage reference value and obtain the action time of corresponding mid-vector;According to the action time relationship of large vector and mid-vector, the action time of corresponding large vector is calculated;According to the action time of mid-vector and large vector, the five-phase duty cycle of inverter for driving motor is calculated.The method can output suitable harmonic voltage without affecting αβ Coordinate system, to inhibit the harmonic current of five-phase permanent magnet synchronous motor.

Description

Technical Field

[0001] This invention relates to the field of permanent magnet synchronous motor control technology, and in particular to a harmonic voltage modulation method and a readable storage medium for a five-phase permanent magnet synchronous motor. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) use permanent magnets for excitation, eliminating the need for problematic slip rings and brushes, resulting in a simpler structure and improved reliability. Furthermore, because no excitation current is required, there are no excitation losses, thus increasing efficiency and power density. Therefore, PMSMs are now widely used in servo drives and electric vehicle drives.

[0003] Compared to ordinary three-phase motors, five-phase permanent magnet synchronous motors have two additional armature windings, which can effectively improve the motor's power density and fault tolerance, and have great application prospects. However, the harmonic space introduced by the five-phase windings will increase harmonic currents, thereby increasing motor losses. Therefore, it is necessary to apply appropriate harmonic voltages to suppress them. Summary of the Invention

[0004] The purpose of this invention is to provide a harmonic voltage modulation method and a readable storage medium for a five-phase permanent magnet synchronous motor, which can output a suitable harmonic control voltage without affecting the control voltage in the αβ coordinate system, thereby suppressing harmonic current and improving motor efficiency.

[0005] To achieve the above objectives, the present invention provides a harmonic voltage modulation method for a five-phase permanent magnet synchronous motor, wherein the harmonic voltage is applied to the motor to suppress the harmonic current of the motor, and the method includes the following steps:

[0006] Calculate the maximum action time of the middle vector of the motor control voltage reference vector in the clockwise and counterclockwise directions in the αβ coordinate system respectively, and then determine the corresponding two action time ranges;

[0007] The two action time ranges are divided into equal parts to obtain two finite sets, and the corresponding harmonic voltages are calculated based on different combinations of values ​​of the two finite sets.

[0008] Select the harmonic voltage that is closest to the harmonic voltage reference value and obtain the corresponding mid-vector's duration of action;

[0009] Calculate the duration of action of the large vector based on the relationship between the duration of action of the large vector and the medium vector.

[0010] The five-phase duty cycle of the inverter used to drive the motor is calculated based on the duration of action of the medium vector and the duration of action of the large vector.

[0011] Optional, in t 1max and t3max Let represent the maximum duration of action of the first intermediate vector in the clockwise direction and the second intermediate vector in the counterclockwise direction, respectively, for the motor control voltage reference vector in the αβ coordinate system. Then we have:

[0012]

[0013] in, To control the value of the voltage reference vector, To control the angle between the voltage reference vector and the α axis, U dc T is the bus voltage. s To control the cycle;

[0014] The range of the action time t1 of the first vector and the action time t3 of the second vector are determined according to the following formula:

[0015]

[0016] If t 1max +t 3max >(t1+t3) max Then t 1max and t 3max Revised to:

[0017]

[0018] Optionally, the value of the motor control voltage reference vector in the αβ coordinate system can be calculated using a vector control method or a direct torque control method. And the angle between the control voltage reference vector and the α axis

[0019] Optionally, the ranges of the two action times t1 and t3 are each divided into equal n parts, resulting in the following finite sets of t1 and t3:

[0020]

[0021] The harmonic voltages calculated based on different combinations of values ​​for the finite set of t1 and t3 are as follows:

[0022]

[0023] Among them, u x and u y Let be the x-component and y-component of the harmonic voltage in the xy coordinate system, respectively. The subscripts i and j represent the i-th t1 and j-th t3 in the corresponding finite set, respectively. n is a natural number greater than 2, and i and j are natural numbers from 1 to n.

[0024] Optionally, selecting the harmonic voltage closest to the harmonic voltage reference value and obtaining the corresponding mid-vector's duration includes:

[0025] The corresponding u is obtained by minimizing the value function. xij and u yij The value function, representing the harmonic voltage closest to the harmonic voltage reference value, is as follows:

[0026]

[0027] in, and The x and y components of the harmonic voltage reference value;

[0028] Determined and obtained u xij and u yij The corresponding action time of the first vector is t1, and the action time of the second vector is t3.

[0029] Optionally, the action time of the large vector is calculated based on the action time relationship between the large vector and the medium vector as follows:

[0030]

[0031] Where t2 and t4 are the durations of action of the first largest vector in the clockwise direction and the second largest vector in the counterclockwise direction, respectively, of the control voltage reference vector.

[0032] Optionally, the five-phase duty cycle is calculated as follows:

[0033]

[0034] t o =T s -t1-t2-t3-t4

[0035] Where, d A d B d C d D and d E These represent the duty cycles of phases A, B, C, D, and E, respectively.

[0036] Optionally, the harmonic voltage reference value can be calculated using a deadbeat control algorithm.

[0037] Based on the same inventive concept, the present invention also provides a readable storage medium having a computer program stored thereon, which, when executed, can realize the harmonic voltage modulation method for a five-phase permanent magnet synchronous motor as described above.

[0038] The harmonic voltage modulation method and readable storage medium for a five-phase permanent magnet synchronous motor provided by this invention have at least one of the following beneficial effects:

[0039] 1) Most general five-phase motor modulation methods cannot provide accurate harmonic voltage or directly force the harmonic voltage to zero. The method proposed in this invention can output a suitable harmonic voltage without affecting the αβ coordinate system, thereby suppressing the harmonic current of the five-phase permanent magnet synchronous motor and improving the motor efficiency.

[0040] 2) This invention can optimize control performance, enabling the five-phase permanent magnet synchronous motor to better leverage its high power output advantage, which is of great significance for the promotion and application of electric traction and large-scale electric equipment. Attached Figure Description

[0041] Those skilled in the art will understand that the accompanying drawings are provided to better understand the invention and do not constitute any limitation on the scope of the invention. Wherein:

[0042] Figure 1 A flowchart of a harmonic voltage modulation method for a five-phase permanent magnet synchronous motor provided in an embodiment of the present invention;

[0043] Figure 2 A voltage vector distribution diagram of a five-phase permanent magnet synchronous motor provided in an embodiment of the present invention;

[0044] Figure 3 This is a flowchart of an embodiment of the present invention for solving a value function optimization problem using KKT conditions;

[0045] Figure 4 A schematic diagram of an experimental control unit provided in an embodiment of the present invention;

[0046] Figure 5 The experimental results before and after harmonic current suppression of a five-phase permanent magnet synchronous motor provided in an embodiment of the present invention;

[0047] Figure 6 This invention provides experimental results of the present invention and virtual voltage vector modulation and four-vector space pulse width modulation on stator current at low motor speeds, as provided in an embodiment of the present invention.

[0048] Figure 7 This invention provides experimental results of the present invention and virtual voltage vector modulation and four-vector space pulse width modulation at rated speed for a specific embodiment of the invention;

[0049] Figure 8 A comparison of the step response of the stator q-axis current at rated speed with virtual voltage vector modulation and four-vector space pulse width modulation provided in an embodiment of the present invention;

[0050] Figure 9A comparison of total harmonic distortion of phase current between different modulation methods under different rotational speeds and phase current amplitudes, provided by an embodiment of the present invention;

[0051] Figure 10 A comparison of the computation time of the five-segment division method in the existing modulation scheme provided in an embodiment of the present invention with that of the present invention;

[0052] Figure 11 A comparison of the switching time of the present invention with that of a five-phase inverter using virtual voltage vector modulation and four-vector space pulse width modulation is provided for one embodiment of the present invention.

[0053] Figure 12 A comparison of the control voltage of the present invention with virtual voltage vector modulation and four-vector space pulse width modulation under rated speed and 4A stator current and finite DC bus voltage is provided for an embodiment of the present invention.

[0054] Figure 13 This invention provides a comparison of the control voltage of the present invention with virtual voltage vector modulation and four-vector space pulse width modulation at rated speed for the step response of q-axis current. Detailed Implementation

[0055] To make the objectives, advantages, and features of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clearly illustrate the purpose of the embodiments of this invention. Please refer to the accompanying drawings to make the objectives, features, and advantages of this invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only used to complement the content disclosed in the specification, for those skilled in the art to understand and read, and are not intended to limit the implementation conditions of this invention. Any modifications to the structure, changes in proportions, or adjustments to the size, if they are the same as or similar to the effects and objectives achieved by this invention, should still fall within the scope of the technical content disclosed in this invention.

[0056] As used herein, the singular forms “a,” “an,” and “the” include plural objects unless otherwise expressly indicated. As used herein, the term “or” is generally used to include the meaning of “and / or” unless otherwise expressly indicated.

[0057] Please refer to Figure 1 This embodiment provides a harmonic voltage modulation method for a five-phase permanent magnet synchronous motor. The harmonic voltage is applied to the motor to suppress the harmonic current of the motor, and includes the following steps:

[0058] S1. Calculate the maximum action time of the middle vector of the motor control voltage reference vector in the clockwise and counterclockwise directions in the αβ coordinate system respectively, and then determine the corresponding two action time ranges.

[0059] S2. Divide the two action time ranges into equal parts to obtain two finite sets, and calculate the corresponding harmonic voltages based on different combinations of values ​​of the two finite sets;

[0060] S3. Select the harmonic voltage that is closest to the harmonic voltage reference value and obtain the corresponding mid-vector action time;

[0061] S4. Calculate the action time of the corresponding large vector based on the action time relationship between the large vector and the medium vector;

[0062] S5. Calculate the five-phase duty cycle of the inverter used to drive the motor based on the duration of action of the medium vector and the duration of action of the large vector.

[0063] First, execute S1 to calculate the maximum action time of the middle vector of the motor control voltage reference vector in the clockwise and counterclockwise directions in the αβ coordinate system, and then determine the corresponding two action time ranges.

[0064] Please refer to Figure 2 ,in, Figure 2 (a) is the αβ coordinate system. Figure 2 (b) is the xy coordinate system. The large vector is the non-zero voltage vector with the largest amplitude in the αβ coordinate system, such as u. 17 u 24 u 25 The vector indicated by the red arrow, the median vector is the non-zero voltage vector adjacent to the larger vector in the αβ coordinate system, such as u. 16 u 27 u 29 The vectors indicated by the blue arrows, such as u9 and u in the αβ coordinate system. 21 u 26 The vectors indicated by the black arrows are small vectors.

[0065] In this embodiment, t 1max and t 3max Let represent the maximum duration of action of the first intermediate vector in the clockwise direction and the second intermediate vector in the counterclockwise direction, respectively, for the motor control voltage reference vector in the αβ coordinate system. Then we have:

[0066]

[0067] in, To control the value of the voltage reference vector, To control the angle between the voltage reference vector and the α axis, Udc T is the bus voltage. s To control the cycle;

[0068] The range of the action time t1 of the first vector and the action time t3 of the second vector are determined according to the following formula:

[0069]

[0070] If t 1max +t 3max >(t1+t3) max Then t 1max and t 3max Revised to:

[0071]

[0072] In this embodiment, existing mature motor control methods can be used, such as vector control methods or direct torque control methods, to calculate the value of the motor control voltage reference vector in the αβ coordinate system. And the angle between the control voltage reference vector and the α axis

[0073] Then, S2 is executed to divide the two action time ranges into equal parts to obtain two finite sets, and the corresponding harmonic voltages are calculated based on the different combinations of values ​​of the two finite sets.

[0074] Specifically, the ranges of the two action times t1 and t3 are each divided into equal n parts, resulting in the following finite sets of t1 and t3:

[0075]

[0076] The harmonic voltages calculated based on different combinations of values ​​for the finite set of t1 and t3 are as follows:

[0077]

[0078] Among them, u x and u y Let be the x-component and y-component of the harmonic voltage in the xy coordinate system, respectively. The subscripts i and j represent the i-th t1 and j-th t3 in the corresponding finite set, respectively. n is a natural number greater than 2, and i and j are natural numbers from 1 to n.

[0079] It should be noted that this invention does not impose any limitation on the number of equal divisions of the action time range. For ease of explanation, in this embodiment, it is assumed that the two action time ranges are divided into the same 6 parts, resulting in the following finite sets of t1 and t3:

[0080]

[0081] By selecting one value from each of the finite sets t1 and t3, enumerating all possible combinations, and calculating the corresponding harmonic voltage, a total of 36 harmonic voltages can be obtained based on the finite sets t1 and t3.

[0082] Next, execute S3, combined with Figure 3 Select the harmonic voltage that is closest to the harmonic voltage reference value and obtain the corresponding mid-vector action time.

[0083] In this embodiment, selecting the harmonic voltage closest to the harmonic voltage reference value and obtaining the corresponding mid-vector's duration includes:

[0084] The corresponding u is obtained by minimizing the value function. xij and u yij The value function, representing the harmonic voltage closest to the harmonic voltage reference value, is as follows:

[0085]

[0086] in, and The x and y components of the harmonic voltage reference value;

[0087] Determined and obtained u xij and u yij The corresponding action time of the first vector is t1, and the action time of the second vector is t3.

[0088] Furthermore, this embodiment solves the optimization problem of the value function based on the KKT conditions. The KKT conditions (Karush-Kuhn-Tucker conditions) are a set of necessary conditions used in mathematical optimization to find the optimal solution to a nonlinear programming problem. These conditions are applicable to optimization problems with inequality and equality constraints. When the problem satisfies certain assumptions (such as the feasibility of constraints, the differentiability of the objective function and constraint functions, and certain regularity conditions), the KKT conditions can provide necessary conditions for a local optimum.

[0089] Specifically, the inequality constraints are constructed as follows:

[0090]

[0091] Determine whether the currently obtained internal solution satisfies the above constraints. If it does, proceed to S4; otherwise, proceed to boundary solution processing and construct the Lagrange function (introducing the Lagrange multiplier μ). j )as follows:

[0092]

[0093] Find the partial derivative and set it to 0:

[0094]

[0095] Further screening of solutions based on complementary relaxation conditions:

[0096]

[0097] The boundary solutions obtained based on the above gradient conditions are used as the final values ​​of t1 and t3.

[0098] In this embodiment, a mature harmonic control algorithm, such as a deadbeat control algorithm, can be used to calculate the harmonic voltage reference value. This invention will not elaborate on this.

[0099] Then, S4 is executed, and the action time of the corresponding large vector is calculated based on the action time relationship between the large vector and the medium vector as follows:

[0100]

[0101] Where t2 and t4 are the durations of action of the first largest vector in the clockwise direction and the second largest vector in the counterclockwise direction, respectively, of the control voltage reference vector.

[0102] Finally, S5 is executed, where t2 and t4 are the action times of the first largest vector in the clockwise direction and the second largest vector in the counterclockwise direction, respectively, of the control voltage reference vector.

[0103] In this embodiment, the five-phase duty cycle is calculated as follows:

[0104]

[0105] t o =T s -t1-t2-t3-t4 (17)

[0106] Where, d A d B d C d D and d E These are the duty cycles of phases A, B, C, D, and E, respectively. Based on the five-phase duty cycles, the five-phase inverter can be driven to control the motor.

[0107] It's worth noting that the mathematical model of a five-phase permanent magnet synchronous motor adds an xy space compared to the αβ space of a three-phase motor. The reference voltage generation of a three-phase motor only needs to consider the voltage vector synthesis in the αβ space, and the modulation is independent. However, in a five-phase motor, each switching mode of the inverter simultaneously generates a basic voltage vector in both the αβ and xy spaces. Therefore, when using the voltage vector in the αβ space to control the five-phase motor, a voltage will be induced in the xy space, meaning that the modulation of the five-phase motor is coupled.

[0108] In existing solutions, adjacent four-vector spatial pulse width modulation (NFV-SVPWM) can modulate the reference voltages in two subspaces, but the modulation process is coupled. If the DC bus voltage is sufficient, the modulation in both subspaces can operate well. However, when the DC bus voltage is limited, the modulation process in the xy space will affect the modulation process in the αβ space, and vice versa. This will result in errors in the modulation of both subspaces and affect the performance of the drive system.

[0109] The harmonic voltage modulation method for a five-phase permanent magnet synchronous motor proposed in this invention is a unique modulation scheme based on nonlinear optimization to synthesize control voltages in two spaces. The advantage of this method is that it eliminates the influence of the xy-space modulation process on the αβ-space modulation process. Therefore, when the DC bus voltage is limited, torque output can be guaranteed first. This method follows a two-step mechanism: first, it ensures the synthesis of the αβ-space control voltage and determines the time constraint of the basic control voltage vector. Second, it uses an objective function to achieve the synthesis of the xy-space control voltage, thereby realizing decoupled modulation of the two subspaces.

[0110] This invention proposes an innovative harmonic voltage modulation method for a five-phase permanent magnet synchronous motor (PMSM), using the value function solution of a nonlinear optimization problem to synthesize the xy subspace reference voltage of the PMSM. The constraint of the nonlinear optimization problem is to guarantee the synthesis of the αβ space reference voltage. The solution process is thoroughly analyzed based on the KKT conditions, and the solution provides the optimal action time of the basic voltage vector. Based on this, the duty cycle of the five-phase inverter is derived. The main contribution of the proposed modulation scheme is its ability to effectively prevent the modulation process in the xy space from affecting the αβ space. Therefore, it can be guaranteed that the αβ space reference voltage is synthesized first, followed by the generation of the relatively optimal xy space control voltage. Thus, the dq axis current or torque output can always be prioritized. This results in better performance of the motor drive system when the DC bus voltage is insufficient or in a transient state. Furthermore, the computation time of this method is much shorter than existing decoupled modulation schemes, and it can also be extended to other multi-phase motors with multiple subspaces, such as six-phase motors.

[0111] The technical effects of the present invention will be further illustrated by some specific experiments below.

[0112] like Figure 4 As shown, the experimental control unit is a Texas Instruments (TI) LAUNCHXL-F28379D microcontroller. The control frequency is 10kHz. The phase current waveform is sampled using a current probe and the microcontroller's onboard analog-to-digital converter (ADC) module. Based on the ADC values, the dq and xy space currents are calculated using VSD and Park transforms. The control voltages in the αβ and xy spaces are calculated based on the inverter's duty cycle. The current probe then sends the phase current data directly to the oscilloscope, while other data is output to the oscilloscope via the DAC81408 digital-to-analog converter (DAC) module.

[0113] It should be noted that the innovation of this invention lies in the optimized design of the voltage modulation algorithm, not in the hardware itself. Although hardware design also affects the harmonic level of the motor system, this invention treats the impact of hardware as an invariant among the control variables. That is, under the same hardware design conditions, this invention can effectively suppress the harmonics and losses of a five-phase permanent magnet synchronous motor.

[0114] like Figure 5 As shown, where, Figure 5 (a) shows the experimental results before the harmonic voltage was applied. Figure 5 (b) shows the experimental results after the harmonic voltage is modulated by the harmonic voltage modulation method of the five-phase permanent magnet synchronous motor provided by the present invention. It can be seen that the present invention can effectively apply the harmonic voltage to the xy plane to suppress the harmonic current.

[0115] like Figure 6 As shown, Figure 6 The present invention, along with Virtual Voltage Vector Modulation (VVV) and Four-Vector Space Pulse Width Modulation (NFV-SVPWM), demonstrates experimental results of stator current at a low motor speed of 100 r / min. Figure 6 (a) is virtual voltage vector modulation. Figure 6 (b) is four-vector spatial pulse width modulation. Figure 6 (C) shows the modulation method proposed in this invention. It can be seen that although the VVV scheme does not generate a control voltage in the motor's xy subspace, harmonic currents are still significant due to various interferences. Using NFV-SVPWM can effectively suppress xy ​​space harmonic currents. However, due to coupling during the modulation process, the dq axis current generates additional ripple. Conversely, the modulation method proposed in this invention can suppress xy ​​space harmonic currents without affecting the current in the dq subspace, achieving a minimum current harmonic distortion rate of 1.04%.

[0116] like Figure 7 As shown, Figure 7The experimental results of this invention, along with Virtual Voltage Vector Modulation (VVV) and Four-Vector Space Pulse Width Modulation (NFV-SVPWM), are presented at rated stator current. Figure 7 (a) is virtual voltage vector modulation. Figure 7 (b) is four-vector spatial pulse width modulation. Figure 7 (C) shows the modulation method proposed in this invention. When a five-phase permanent magnet synchronous motor operates at a high speed (400 r / min), the xy-space harmonic current suppression performance of NFV-SVPWM becomes very limited. Furthermore, ripple is also generated in the dq-space current. In contrast, the modulation method proposed in this invention can still reduce harmonic current. Moreover, the dq-space current is not affected.

[0117] like Figure 8 As shown, Figure 8 This paper demonstrates the step response of the stator q-axis current at rated speed compared to the present invention and virtual voltage vector modulation (VV-SVPWM) and four-vector space pulse width modulation (NFV-SVPWM). It can be seen that using the modulation method proposed in this invention, the control system reaches the reference value of iq in the shortest time, approximately 0.97 milliseconds. In comparison, the VVV-based modulation scheme takes 1.38 milliseconds, while NFV-SVPWM takes 2.24 milliseconds. The results prove that the modulation method proposed in this invention helps improve the transient performance of a five-phase permanent magnet synchronous motor drive system.

[0118] like Figure 9 As shown, Figure 9 A comparison of the total harmonic distortion (THD) of the phase current under different speeds and phase current amplitudes is presented to further verify the performance of the modulation method proposed in this invention. It can be seen that the modulation method proposed in this invention can effectively reduce the phase current THD under all operating conditions. However, the harmonic current control performance of NFV-SVPWM deteriorates as the rotor speed increases.

[0119] like Figure 10 As shown, Figure 10 A comparison of the computation time between the existing five-segment division method and the modulation method proposed in this invention is presented. The results show that the modulation process of the existing scheme takes 34 μs, while the method proposed in this invention only takes 10 μs.

[0120] like Figure 11 As shown, Figure 11 The switching times of a five-phase inverter using this invention and two existing modulation schemes are illustrated, which correspond to the modulation signals. Figure 11 (a) is virtual voltage vector modulation. Figure 11 (b) is four-vector spatial pulse width modulation. Figure 11(C) represents the modulation method proposed in this invention. It can be observed that NFV-SVPWM operates outside the linear modulation region because the DC bus voltage is insufficient to support the control voltages in the αβ and xy spaces. Nevertheless, some zero-sequence components still exist in the modulated signal of the modulation method proposed in this invention, meaning that the modulation process remains almost linear. This makes u αβ Capable of accurately synthesizing and ensuring i dq control

[0121] like Figure 12 As shown, Figure 12 The invention is compared with two existing modulation schemes in terms of control voltage under rated speed, 4A stator current, and finite DC bus voltage. Figure 12 (a) is virtual voltage vector modulation. Figure 12 (b) is four-vector spatial pulse width modulation. Figure 12 (C) is the modulation method proposed in this invention. Figure 12 In (a), due to the use of a virtual voltage vector, the control voltage in the xy space is canceled out. Then, the maximum amplitude of the control voltage vector in the αβ space is 0.5527Udc, insufficient to maintain rotor speed and stator current. Therefore, there is some error between the actual control voltage and the reference value in the αβ space. This results in some ripple in the αβ space. For the NFV-SVPWM scheme, this problem becomes more severe because it still attempts to synthesize a specific xy space control voltage u in this case. xy .like Figure 12 As shown in (b), although a specific u was generated according to the instruction... xy However, the error between the actual control voltage and the reference voltage in the αβ space is more significant. For example... Figure 12 As shown in (c), the αβ space control voltage u αβ Strictly adhere to the reference value. Therefore, i dq The ripple in this method is much smaller than the other two methods.

[0122] like Figure 13 As shown, Figure 13 The control voltage of the present invention and two existing modulation schemes is compared in terms of the step response of the q-axis current at rated speed. Figure 13 (a) is virtual voltage vector modulation. Figure 13 (b) is four-vector spatial pulse width modulation. Figure 13 (C) is the modulation method proposed in this invention. For example... Figure 13 As shown in (a), when the voltage is insufficient, u αβ Errors arise between the reference value and the actual value. These errors become even larger when using NFV-SVPWM, such as... Figure 13 As shown in (b), because u xyThe synthesis process consumes some DC bus voltage. However, by using the modulation method proposed in this invention, it is possible to first ensure that u αβ The synthesis. The DC bus voltage is first used to generate u. αβ Therefore, u αβ There is almost no error between it and the reference value, such as Figure 13 As shown in (c).

[0123] Based on the same inventive concept, embodiments of the present invention also propose a readable storage medium storing a computer program thereon, which, when executed, can realize the harmonic voltage modulation method of the five-phase permanent magnet synchronous motor as described above.

[0124] A readable storage medium can be a tangible device capable of holding and storing instructions for use by an instruction execution device, such as, but not limited to, electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination thereof. More specific examples of readable storage media (a non-exhaustive list) include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any suitable combination thereof. The computer programs described herein can be downloaded from the readable storage medium to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. Networks can include copper transmission cables, fiber optic transmissions, wireless transmissions, routers, firewalls, switches, gateway computers, and / or edge servers. Each computing / processing device's network adapter card or network interface receives and forwards a computer program from the network for storage on a readable storage medium within the various computing / processing devices. The computer program used to perform the operations of this invention can be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, status setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as "C" or similar languages. The computer program can execute entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuits, such as programmable logic circuits, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), are personalized by utilizing state information from a computer program. These electronic circuits can execute computer-readable program instructions, thereby realizing various aspects of the invention.

[0125] Various aspects of the invention are described herein with reference to flowchart illustrations and / or block diagrams of methods, systems, and computer program products according to embodiments of the invention. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by a computer program. These computer programs can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine such that, when executed by the processor of the computer or other programmable data processing apparatus, they create means for implementing the functions / actions specified in one or more blocks of the flowchart illustrations and / or block diagrams. These computer programs can also be stored in a readable storage medium that causes a computer, programmable data processing apparatus, and / or other device to operate in a particular manner; thus, the readable storage medium storing the computer program comprises an article of manufacture including instructions for implementing various aspects of the functions / actions specified in one or more blocks of the flowchart illustrations and / or block diagrams.

[0126] A computer program may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process, thereby causing the computer program executing on the computer, other programmable data processing apparatus, or other device to perform the functions / actions specified in one or more boxes of a flowchart and / or block diagram.

[0127] In summary, one embodiment of the present invention provides a harmonic voltage modulation method and a readable storage medium for a five-phase permanent magnet synchronous motor. This method can output appropriate harmonic voltages without affecting the αβ coordinate system, thereby suppressing harmonic currents in the five-phase permanent magnet synchronous motor and improving motor efficiency. Furthermore, the present invention optimizes control performance, enabling the five-phase permanent magnet synchronous motor to better leverage its high-power output advantages, which is of great significance for the widespread application of electric traction and large-scale electric equipment.

[0128] Furthermore, it should be understood that although the present invention has been disclosed above with reference to preferred embodiments, these embodiments are not intended to limit the present invention. For any person skilled in the art, many possible variations and modifications can be made to the technical solutions of the present invention based on the disclosed technical content, or equivalent embodiments can be modified accordingly, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the present invention, shall still fall within the scope of protection of the present invention.

Claims

1. A harmonic voltage modulation method for a five-phase permanent magnet synchronous motor, wherein the harmonic voltage is applied to the motor to suppress the harmonic current of the motor, characterized in that, The method includes the following steps: Calculate the maximum action time of the middle vector of the motor control voltage reference vector in the clockwise and counterclockwise directions in the αβ coordinate system respectively, and then determine the corresponding two action time ranges; The two action time ranges are divided into equal parts to obtain two finite sets, and the corresponding harmonic voltages are calculated based on different combinations of values ​​of the two finite sets. Select the harmonic voltage that is closest to the harmonic voltage reference value and obtain the corresponding mid-vector's duration of action; Calculate the duration of action of the large vector based on the relationship between the duration of action of the large vector and the medium vector. The five-phase duty cycle of the inverter used to drive the motor is calculated based on the duration of action of the medium vector and the duration of action of the large vector.

2. The harmonic voltage modulation method for a five-phase permanent magnet synchronous motor according to claim 1, characterized in that, With t 1max and t 3max Let represent the maximum duration of action of the first intermediate vector in the clockwise direction and the second intermediate vector in the counterclockwise direction, respectively, for the motor control voltage reference vector in the αβ coordinate system. Then we have: in, To control the value of the voltage reference vector, To control the angle between the voltage reference vector and the α axis, U dc T is the bus voltage. s To control the cycle; The range of the action time t1 of the first vector and the action time t3 of the second vector are determined according to the following formula: If t 1max +t 3max >(t1+t3) max Then t 1max and t 3max Revised to:

3. The harmonic voltage modulation method for a five-phase permanent magnet synchronous motor according to claim 2, characterized in that, The value of the motor control voltage reference vector in the αβ coordinate system is calculated using vector control or direct torque control methods. And the angle between the control voltage reference vector and the α axis 4. The harmonic voltage modulation method for a five-phase permanent magnet synchronous motor according to claim 2, characterized in that, Dividing the ranges of the two action times t1 and t3 into equal n parts, we obtain the following finite sets of t1 and t3: The harmonic voltages calculated based on different combinations of values ​​for the finite set of t1 and t3 are as follows: Among them, u x and u y Let be the x-component and y-component of the harmonic voltage in the xy coordinate system, respectively. The subscripts i and j represent the i-th t1 and j-th t3 in the corresponding finite set, respectively. n is a natural number greater than 2, and i and j are natural numbers from 1 to n.

5. The harmonic voltage modulation method for a five-phase permanent magnet synchronous motor according to claim 4, characterized in that, Selecting the harmonic voltage closest to the harmonic voltage reference value and obtaining the corresponding mid-vector's duration includes: The corresponding u is obtained by minimizing the value function. xij and u yij The value function, representing the harmonic voltage closest to the harmonic voltage reference value, is as follows: in, and The x and y components of the harmonic voltage reference value; Determined and obtained u xij and u yij The corresponding action time of the first vector is t1, and the action time of the second vector is t3.

6. The harmonic voltage modulation method for a five-phase permanent magnet synchronous motor according to any one of claims 2-5, characterized in that, The duration of action of the large vector is calculated based on the relationship between the durations of action of the large and medium vectors as follows: Where t2 and t4 are the durations of action of the first largest vector in the clockwise direction and the second largest vector in the counterclockwise direction, respectively, of the control voltage reference vector.

7. The harmonic voltage modulation method for a five-phase permanent magnet synchronous motor according to claim 6, characterized in that, The five-phase duty cycle is calculated as follows: t o =T s -t1-t2-t3-t4 Where, d A d B d C d D and d E These represent the duty cycles of phases A, B, C, D, and E, respectively.

8. The harmonic voltage modulation method for a five-phase permanent magnet synchronous motor according to claim 1, characterized in that, The harmonic voltage reference value is calculated using a deadbeat control algorithm.

9. A readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed, it can implement the harmonic voltage modulation method for the five-phase permanent magnet synchronous motor according to any one of claims 1-8.

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