Variable conduction mode based multiphase motor efficiency optimization method, system, and apparatus

Abstract

The application relates to the field of motor control and provides a variable conduction mode-based multi-phase motor efficiency optimization method, system and device, which comprises the following steps: constructing a torque expression and determining the number of conduction phases, so as to determine a maximum torque limit; constructing a total copper loss expression, calculating a phase current effective value, calculating a phase copper loss based on the total copper loss expression and the phase current effective value; constructing an odd-phase conduction loss expression and an even-phase conduction loss expression, and calculating inverter conduction loss according to the odd-phase conduction loss expression and the even-phase conduction loss expression; calculating inverter switch loss, obtaining inverter loss through the inverter conduction loss and the inverter switch loss, obtaining motor total loss according to the inverter loss and the phase copper loss; obtaining an optimal number of conduction phases through the motor total loss under the constraint of the maximum torque limit, adjusting the running phase of a target motor according to the optimal number of conduction phases, and completing the control of the target motor.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of motor control, and in particular to a multi-phase motor efficiency optimization method, system and device based on a variable conduction mode. BACKGROUND

[0002] As the core power equipment of modern industry and transportation systems, motors play a crucial role in energy utilization, automation control, and high-end equipment. With the rapid development of emerging applications such as electric vehicles, new energy generation, aerospace, and high-performance industrial drives, the demand for efficient and reliable operation of motors is increasing. Compared to traditional three-phase motors, multi-phase motors have higher power density, stronger fault tolerance, and lower torque ripple, making them an important technical device to meet these demands.

[0003] Multi-phase brushless DC motors have been widely researched and applied due to their simple structure, flexible control, and high reliability. In existing technologies, multi-phase brushless DC motors are usually controlled using a fixed conduction mode. Under different loads and operating conditions, the loss distribution of the multi-phase brushless DC motor system varies significantly. At light load, the power device switching loss increases, reducing the efficiency of the inverter. At heavy load, the phase current is too large, and the winding copper loss increases significantly, restricting the system performance. This fixed control method cannot achieve high efficiency under all operating conditions. SUMMARY

[0004] The present application aims to at least solve one of the technical problems in the related art. To this end, the present application provides a multi-phase motor efficiency optimization method, system and device based on a variable conduction mode, which balances the copper loss and inverter loss while ensuring the efficiency of the motor.

[0005] The present application provides a multi-phase motor efficiency optimization method, system and device based on a variable conduction mode, comprising:

[0006] S1: Determine the target motor, construct the torque expression and determine the number of conduction phases, and determine the maximum torque limit according to the torque expression and the number of conduction phases;

[0007] S2: Calculate the current average copper loss, construct the total copper loss expression through the current average copper loss, calculate the phase current effective value, and calculate the phase copper loss based on the total copper loss expression and the phase current effective value;

[0008] S3: Construct the odd-phase conduction loss expression and the even-phase conduction loss expression, and calculate the inverter conduction loss according to the odd-phase conduction loss expression and the even-phase conduction loss expression;

[0009] S4: calculate the inverter switching loss, obtain the inverter loss through the inverter conduction loss and the inverter switching loss, obtain the total motor loss through the inverter loss and the phase copper loss;

[0010] S5: obtain the optimal conduction phase number through the total motor loss under the constraint of the maximum torque limit, adjust the running phase of the target motor according to the optimal conduction phase number, and complete the control of the target motor.

[0011] According to the multi-phase motor efficiency optimization method based on the variable conduction mode provided by the application, step S1 further comprises:

[0012] S11: determine the multi-phase motor as the target motor, determine the mechanical angular velocity and the back electromotive force amplitude of the target motor, and obtain a torque expression according to the mechanical angular velocity and the back electromotive force amplitude;

[0013] S12: determine the conduction phase number and the maximum allowable current, and substitute the conduction phase number and the maximum allowable current into the torque expression to obtain the maximum torque limit.

[0014] According to the multi-phase motor efficiency optimization method based on the variable conduction mode provided by the application, in step S2, the current instantaneous copper loss is calculated, the current average copper loss is obtained according to the current instantaneous copper loss, and the total copper loss expression is constructed through the current average copper loss.

[0015] According to the multi-phase motor efficiency optimization method based on the variable conduction mode provided by the application, in step S2, the odd phase phase current effective value and the even phase phase current effective value are constructed, and the odd phase phase current effective value and the even phase phase current effective value are brought into the total copper loss expression to obtain the phase copper loss.

[0016] According to the multi-phase motor efficiency optimization method based on the variable conduction mode provided by the application, in step S3, the odd phase conduction loss expression is:

[0017]

[0018] wherein, is the conduction loss under the n-2 phase, d is the duty cycle during conduction, is the resistance of the IGBT, is the phase current amplitude under the n-2 phase, is the zero-current conduction voltage drop of the IGBT, is the resistance of the diode, is the zero-current conduction voltage drop of the diode, and n is the phase number of the target motor.

[0019] According to the variable conduction mode based multiphase motor efficiency optimization method provided by the application, in step S3, the even-phase conduction loss expression is:

[0020]

[0021] wherein, is the conduction loss of the n-1th phase, d is the duty cycle during conduction, n is the number of phases of the target motor, is the zero-current conduction voltage drop of the IGBT, is the resistance of the diode, is the zero-current conduction voltage drop of the diode, is the resistance of the IGBT, is the phase current amplitude of the n-1th phase.

[0022] According to the variable conduction mode based multiphase motor efficiency optimization method provided by the application, in step S4, after obtaining the inverter switch loss, the inverter switch loss and the inverter conduction loss are added to obtain the inverter loss, and the inverter loss and the phase copper loss are added to obtain the total motor loss.

[0023] According to the variable conduction mode based multiphase motor efficiency optimization method provided by the application, in step S5, the torque when the total motor loss between adjacent phases is equal is taken as the critical torque, and the critical torque is constrained by the maximum torque limit to obtain the optimal number of conduction phases;

[0024] The hysteresis width is determined, and the torque change indication value is determined, and the running phase of the target motor is adjusted according to the optimal number of conduction phases, the torque change indication value and the hysteresis width.

[0025] The application also provides a variable conduction mode based multiphase motor efficiency optimization system, comprising:

[0026] The maximum torque limit module is used for determining the target motor, constructing the torque expression and determining the number of conduction phases, and determining the maximum torque limit according to the torque expression and the number of conduction phases.

[0027] The phase copper loss module is used for calculating the current average copper loss, constructing the total copper loss expression through the current average copper loss, calculating the phase current effective value, and calculating the phase copper loss based on the total copper loss expression and the phase current effective value.

[0028] The inverter conduction loss module is used for constructing the odd-phase conduction loss expression and the even-phase conduction loss expression, and calculating the inverter conduction loss according to the odd-phase conduction loss expression and the even-phase conduction loss expression.

[0029] Motor total loss module: used for calculating inverter switch loss, obtaining inverter loss through inverter conduction loss and inverter switch loss, obtaining motor total loss according to inverter loss and phase copper loss;

[0030] Motor control module: used for obtaining optimal conduction phase number through motor total loss under the constraint of maximum torque limitation, adjusting operation phase of the target motor according to the optimal conduction phase number, and completing control of the target motor.

[0031] The application also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method for optimizing efficiency of a multiphase motor based on a variable conduction mode according to the above-mentioned any one of the method.

[0032] The one or more technical solutions in the embodiments of the application have at least one of the following technical effects:

[0033] The method, system and device for optimizing efficiency of a multiphase motor based on a variable conduction mode provided by the application obtain the optimal conduction phase number through calculation of motor total loss, so that the motor can select a suitable phase number under different torques, thereby making the copper loss of the motor smaller, improving the operation efficiency and service life of the motor, and being applicable to target motors of different phases, in addition, the efficiency optimization can be realized only through a control strategy without increasing additional hardware devices, thereby reducing system cost and implementation complexity, and thus having good engineering implementability and universality.

[0034] Additional aspects and advantages of the application will be described in the following description and will become apparent from the following detailed description or will be learned by practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0036] Figure 1 is a flowchart of the method for optimizing efficiency of a multiphase motor based on a variable conduction mode provided by the application.

[0037] Figure 2 is a circuit schematic diagram of a nine-phase brushless direct current motor of the method for optimizing efficiency of a multiphase motor based on a variable conduction mode provided by the application.

[0038] Figure 3It is structural schematic view of variable conduction mode based multiphase motor efficiency optimization system provided by the application.

[0039] Figure 4 It is structural schematic view of variable conduction mode based multiphase motor efficiency optimization device provided by the application.

[0040] Reference signs:

[0041] 100, maximum torque limiting module; 200, phase copper loss module; 300, inverter conduction loss module; 400, motor total loss module; 500, motor control module; 810, processor; 820, communication interface; 830, memory; 840, communication bus. DETAILED DESCRIPTION

[0042] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be clearly and completely described below. Obviously, the described embodiments are some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application. The following embodiments are used to illustrate the present application, but cannot be used to limit the scope of the present application.

[0043] In the description of the embodiments of the present application, it should be noted that the terms "first", "second", "third" are only used for description purpose, and cannot be understood as indicating or implying relative importance.

[0044] In the description of the embodiments of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "connected", "connected" should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0045] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine the different embodiments or examples described in the present application and the features of different embodiments or examples without contradiction.

[0046] The application is described below in conjunction with Figures 1 to 4 The specific embodiments of the application are described below, Figure 1 is a flowchart of the method for optimizing the efficiency of a variable conduction mode-based multiphase motor provided by the application, which comprises:

[0047] S1: determining a target motor, constructing a torque expression and determining the number of conduction phases, and determining the maximum torque limit according to the torque expression and the number of conduction phases;

[0048] Further, the purpose of this stage is to construct a torque expression and determine the number of conduction phases, so as to determine the maximum torque limit. Specifically, step S1 further comprises:

[0049] S11: determining a multiphase motor as the target motor, determining the mechanical angular velocity and the back EMF amplitude of the target motor, and obtaining a torque expression according to the mechanical angular velocity and the back EMF amplitude;

[0050] S12: determining the number of conduction phases and the maximum allowable current, and substituting the number of conduction phases and the maximum allowable current into the torque expression to obtain the maximum torque limit.

[0051] For the above steps, the specific embodiments in this embodiment are as follows:

[0052] First, it is necessary to determine a multiphase motor as the target motor. In this embodiment, the target motor is a nine-phase brushless DC motor, and its circuit schematic diagram is shown in Figure 2 Subsequently, the mechanical angular velocity ω and the back EMF amplitude E of the target motor when working at the mth phase are determined according to the working parameters of the target motor, so as to obtain the torque expression of the torque at the mth phase:

[0053]

[0054] wherein, is the phase current amplitude at the mth phase, is the back EMF coefficient.

[0055] Then, the number of conduction phases is determined. Here, the available conduction phases of the nine-phase brushless DC motor when working are 2-8, and in addition, the maximum allowable current of the target motor needs to be determined. Subsequently, by taking the maximum allowable current as the phase current amplitude at different phases, the maximum output torque allowed at different conduction phases, i.e., the maximum torque limit, can be obtained. The maximum torque limit is shown in Table 1:

[0056] Table 1 Maximum torque limit at each phase

[0057]

[0058] wherein T N is the maximum torque that the target motor can output. The maximum torque limit can be used as a limiting parameter, and the output torque of each phase cannot exceed the maximum torque limit.

[0059] S2: calculate the current average copper loss, construct a total copper loss expression through the current average copper loss, calculate the phase current effective value, and calculate the phase copper loss based on the total copper loss expression and the phase current effective value;

[0060] Further, the purpose of this stage is to construct a total copper loss expression, so as to calculate the phase copper loss. Specifically, in step S2, the current instantaneous copper loss is calculated, the current average copper loss is obtained according to the current instantaneous copper loss, and the total copper loss expression is constructed through the current average copper loss.

[0061] In step S2, the odd-phase phase current effective value and the even-phase phase current effective value are constructed, and the odd-phase phase current effective value and the even-phase phase current effective value are brought into the total copper loss expression to obtain the phase copper loss.

[0062] For the above steps, the specific implementation in this embodiment is as follows:

[0063] During the operation of the target motor, the iron loss and the mechanical loss are mainly caused by the change of the speed, and are irrelevant to the phase. Here, the copper loss and the inverter loss related to the phase are focused on. The essence of the copper loss is the Joule loss on the winding resistance. For any phase winding, the instantaneous copper loss at time t can be expressed as :

[0064]

[0065] wherein, is the instantaneous current of the winding at time t, is the resistance of the motor stator. Further, under the steady-state operating condition, the current average copper loss of the phase can be obtained by averaging over an electric period :

[0066]

[0067] wherein, is the length of an electric current period, is the integral over time t, is the phase current effective value in an electric current period. Since the target motor is of a symmetrical winding structure, the winding parameters of each conduction phase are consistent under a given conduction mode, and the phase copper loss of the mth phase is The total copper loss expression of the mth phase is:

[0068]

[0069] wherein, is the phase current effective value at the mth phase in a current cycle, for a brushless DC motor, the relationship between the phase current effective value and the phase current amplitude is different due to the different conduction modes, and the current effective value is difficult to directly measure. Here, first construct the odd phase phase current effective value, first need to make the phase take an odd number, set the number of phases of the target motor as n, since in this embodiment, the target motor is a nine-phase brushless DC motor, so when the number of phases is n-2, it is an odd number, then:

[0070]

[0071] wherein, is the upper half cycle phase current effective value at the n-2th phase, is the lower half cycle phase current effective value at the n-2th phase, is the upper half cycle phase current amplitude at the n-2th phase, is the lower half cycle phase current amplitude at the n-2th phase. Due to the symmetry condition, the current effective value of the upper half cycle is equal to the upper half cycle current effective value, and the current amplitude of the upper half cycle is equal to the upper half cycle current amplitude, so the odd phase phase current effective value at the n-2th phase is:

[0072]

[0073] wherein, is the phase current amplitude at the n-2th phase, is the phase current effective value at the n-2th phase.

[0074] For even phase phase current effective value, when the number of phases is n-1, it is an even number, at this time the even phase phase current effective value is:

[0075]

[0076] wherein, is the phase current effective value at the n-1th phase, is the phase current amplitude at the n-1th phase. Due to the symmetry of the target motor, the conclusions at the n-1th phase and the n-2th phase can be extended to all phases, at this time replace the n-2th and the n-1th phase with the mth phase, that is, the phase current effective value at the mth phase in a current cycle is obtained:

[0077]

[0078] wherein, is the phase current amplitude at the mth phase. At this time, the phase current effective value at the mth phase is substituted into the total copper loss expression, and the phase copper loss is obtained:

[0079]

[0080] Thus, the phase copper loss in the mth phase can be obtained by the easily measured phase current amplitude. It can be seen that the motor copper loss is mainly determined by the phase current. When the number of conducting phases decreases, the phase current amplitude increases to maintain the same torque output, thereby causing the copper loss to increase; when the number of conducting phases increases, the phase current amplitude decreases, and the copper loss correspondingly decreases.

[0081] S3: constructing an odd-phase conduction loss expression and an even-phase conduction loss expression, and calculating the inverter conduction loss according to the odd-phase conduction loss expression and the even-phase conduction loss expression;

[0082] Further, the purpose of this stage is to construct an odd-phase conduction loss expression and an even-phase conduction loss expression, so as to calculate the inverter conduction loss. Specifically, in step S3, the odd-phase conduction loss expression is:

[0083]

[0084] wherein, is the conduction loss in the n-2th phase, d is the duty cycle during conduction, is the resistance of the IGBT, is the phase current amplitude in the n-2th phase, is the zero-current conduction voltage drop of the IGBT, is the resistance of the diode, is the zero-current conduction voltage drop of the diode, and n is the number of phases of the target motor.

[0085] In step S3, the even-phase conduction loss expression is:

[0086]

[0087] wherein, is the conduction loss in the n-1th phase, d is the duty cycle during conduction, and n is the number of phases of the target motor, is the zero-current conduction voltage drop of the IGBT, is the resistance of the diode, is the zero-current conduction voltage drop of the diode, is the resistance of the IGBT, is the phase current amplitude in the n-1th phase.

[0088] For the above steps, the specific implementation manner in this embodiment is as follows:

[0089] The inverter loss mainly includes two parts of conduction loss and switching loss, wherein the conduction loss in the mth phase is The on-resistance of the IGBT and diode participating in conduction and the current passing through them determine:

[0090]

[0091] wherein, is the number of IGBTs (Insulate-Gate Bipolar Transistor) participating in conduction at the mth phase, is the number of diodes participating in conduction at the mth phase, is the resistance of the IGBT, is the effective value of the current flowing through the IGBT, is the zero-current on-voltage drop of the IGBT, is the average value of the current flowing through the IGBT, is the resistance of the diode, is the effective value of the current flowing through the diode, is the average value of the current flowing through the diode, is the zero-current on-voltage drop of the diode.

[0092] Then, the odd-numbered on-loss is constructed. Here, as described in step S2, when the number of phases is n-2, which is an odd number, the odd-numbered on-loss can be obtained as:

[0093]

[0094] wherein, is the on-loss at the n-2th phase, which can be generalized to the on-loss at the odd-numbered phase, that is, the odd-numbered on-loss, and d is the duty cycle when conducting.

[0095] As described in step S2, when the number of phases is n-1, which is an even number, the even-numbered on-loss expression is:

[0096]

[0097] wherein, is the on-loss at the n-1th phase, which can be generalized to the on-loss at the even-numbered phase, that is, the even-numbered on-loss.

[0098] Further, using the torque expression due to the symmetry of the target motor, the conclusions at the n-1th phase and the n-2th phase can be generalized to all phases. At this time, the n-2th and the n-1th phase are replaced with the mth phase, and other parameters related to n are replaced with corresponding parameters related to m, so as to obtain the inverter on-loss at the mth phase is:

[0099]

[0100] wherein the following relation holds:

[0101]

[0102] wherein, is a first even loss parameter, is a second even loss parameter, is a first odd loss parameter, is a second odd loss parameter.

[0103] S4: calculating the inverter switching loss, obtaining the inverter loss by the inverter conduction loss and the inverter switching loss, obtaining the motor total loss according to the inverter loss and the phase copper loss; further, the purpose of this stage is to obtain the inverter loss, so as to obtain the motor total loss. Specifically, in step S4, after obtaining the inverter switching loss, the inverter switching loss and the inverter conduction loss are added to obtain the inverter loss, and the inverter loss and the phase copper loss are added to obtain the motor total loss.

[0104] For the above steps, the specific implementation in this embodiment is as follows:

[0105] First, the inverter switching loss under the mth phase is calculated :

[0106]

[0107] wherein, is the switching frequency of the inverter when the motor is working, is the total energy loss of the opening and closing obtained by the experiment. Then the inverter switching loss and the inverter conduction loss are added, that is, the inverter loss under the mth phase :

[0108]

[0109] Here it can be seen that the inverter conduction loss is related to the number of conduction phases and the phase current amplitude, and when the number of conduction phases increases, the number of power devices participating in conduction increases; the switching loss is related to the switching frequency of the power device and the number of bridge arms participating in conduction. When the number of conduction phases is small, the inverter loss is relatively low, and when the number of conduction phases is too large, the inverter loss increases significantly. Finally, the inverter loss and the phase copper loss are added, that is, the motor total loss is obtained.

[0110] S5: obtaining the optimal conduction phase number by the motor total loss under the constraint of the maximum torque limitation, adjusting the running phase of the target motor according to the optimal conduction phase number, and completing the control of the target motor.

[0111] Further, the purpose of this stage is to obtain the optimal number of conducting phases, so as to adjust the operating phase of the target motor and complete the control of the target motor. Specifically, in step S5, the torque when the total motor loss between adjacent phases is equal is taken as the critical torque, and the critical torque is constrained by the maximum torque limit to obtain the optimal number of conducting phases;

[0112] The hysteresis width is determined, and the torque change indication value is determined. The operating phase of the target motor is adjusted according to the optimal number of conducting phases, the torque change indication value, and the hysteresis width.

[0113] For the above steps, the specific implementation in this embodiment is as follows:

[0114] Here, for each group of adjacent phases, such as the 8th phase and the 7th phase, and the 7th phase and the 6th phase, a group of adjacent phases is substituted respectively, and different torque values are substituted, and it is ensured that the substituted torque values meet the limit of the maximum torque limit. The torque when the total motor loss between adjacent phases is equal can be found, and the critical torque can be found. For the critical torque, when the torque of the actual load of the target motor is less than the critical torque, using the smaller phase in the adjacent phase can reduce the loss of the operation of the target motor, and when the torque of the actual load of the target motor is greater than the critical torque, using the larger phase in the adjacent phase can improve the operating efficiency.

[0115] According to the critical torque, the optimal number of conducting phases can be obtained, that is, in the torque interval determined by the critical torque, the number of phases working can achieve smaller loss and higher efficiency. The optimal number of conducting phases in this embodiment is shown in Table 2:

[0116] Table 2 Optimal number of conducting phases and torque interval relationship table

[0117]

[0118] In the actual operation, according to the torque of the target motor load, the corresponding optimal number of conducting phases can be found, so as to adjust the phase of the target motor.

[0119] In actual operation, if the torque of the target motor repeatedly fluctuates around the critical torque, the phase of the target motor may repeatedly switch, thereby causing unstable operation. Therefore, a hysteresis width needs to be set, that is, a torque value is artificially determined. In addition, a torque change indication value needs to be determined. Here, the torque change indication value is 1 when the torque continuously increases for a period of time, the torque change indication value is 0 when the torque continuously decreases for a period of time, and the torque change indication value is -1 otherwise. When the torque change indication value is 1 and the torque is close to the latest critical torque, the number of conducting phases of the target motor is increased when the torque value reaches the latest critical torque plus the hysteresis width. Similarly, when the torque change indication value is 0 and the torque is close to the latest critical torque, the number of conducting phases of the target motor is decreased when the torque value reaches the latest critical torque minus the hysteresis width, and the torque change indication value is -1, the number of conducting phases is temporarily unchanged.

[0120] To match the switching of different conducting modes, the feedback value of the current loop is also switched. In the current conducting mode, the currents of all non-commutated windings are collected, and the average value thereof is calculated as the current feedback in the conducting mode, which forms a closed-loop current control with the reference current to generate the duty cycle of pulse width modulation and adjust the actual current. Since the number of phases participating in conduction is different in different conducting modes, to ensure consistent dynamic characteristics of the current loop before and after mode switching, the currents of all non-commutated windings need to be collected in each conducting mode, and the average value thereof is calculated as a unified current feedback signal.

[0121] Subsequently, a proportional-integral closed-loop current regulator is constructed using the average current and the reference current to generate the duty cycle of pulse width modulation and act on the inverter to quickly track the expected current command. Further, using the average current as the feedback quantity can effectively eliminate the differences in current sampling structure caused by conducting mode switching, so that the current loop maintains uniform control characteristics in different conducting modes, avoids current mutation at the switching moment, and improves the robustness and stability of the overall control system.

[0122] The variable-conducting-mode-based multiphase motor efficiency optimization device provided by the application is described below. The variable-conducting-mode-based multiphase motor efficiency optimization device described below can be referred to in correspondence with the variable-conducting-mode-based multiphase motor efficiency optimization method described above.

[0123] Figure 3 An example of a structural schematic diagram of a variable-conducting-mode-based multiphase motor efficiency optimization system is shown in Figure 3 for performing the variable-conducting-mode-based multiphase motor efficiency optimization method as described above, including:

[0124] The maximum torque limiting module 100 is configured to determine a target motor, construct a torque expression and determine a number of conducting phases, determine a maximum torque limit according to the torque expression and the number of conducting phases.

[0125] The phase copper loss module 200 is configured to calculate a current average copper loss, construct a total copper loss expression according to the current average copper loss, calculate a phase current effective value, and calculate a phase copper loss based on the total copper loss expression and the phase current effective value.

[0126] The inverter conducting loss module 300 is configured to construct an odd-phase conducting loss expression and an even-phase conducting loss expression, and calculate an inverter conducting loss according to the odd-phase conducting loss expression and the even-phase conducting loss expression.

[0127] The motor total loss module 400 is configured to calculate an inverter switching loss, obtain an inverter loss according to the inverter conducting loss and the inverter switching loss, and obtain a motor total loss according to the inverter loss and the phase copper loss.

[0128] The motor control module 500 is configured to obtain an optimal number of conducting phases according to the motor total loss under the constraint of the maximum torque limit, adjust a running phase of the target motor according to the optimal number of conducting phases, and complete control of the target motor.

[0129] Figure 4 An example of a schematic diagram of a physical structure of an electronic device is shown in Figure 4 The electronic device can include a processor 810, a communications interface 820, a memory 830, and a communications bus 840, wherein the processor 810, the communications interface 820, and the memory 830 can communicate with each other through the communications bus 840. The processor 810 can invoke a computer program in the memory 830 to execute a variable conducting mode-based multi-phase motor efficiency optimization method, which includes:

[0130] S1: determining a target motor, constructing a torque expression and determining a number of conducting phases, and determining a maximum torque limit according to the torque expression and the number of conducting phases;

[0131] S2: calculating a current average copper loss, constructing a total copper loss expression according to the current average copper loss, calculating a phase current effective value, and calculating a phase copper loss based on the total copper loss expression and the phase current effective value.

[0132] S3: constructing an odd-phase conducting loss expression and an even-phase conducting loss expression, and calculating an inverter conducting loss according to the odd-phase conducting loss expression and the even-phase conducting loss expression.

[0133] S4: calculate the inverter switching loss, obtain the inverter loss through the inverter conduction loss and the inverter switching loss, obtain the motor total loss through the inverter loss and the phase copper loss;

[0134] S5: obtain the optimal conduction phase number through the motor total loss under the constraint of the maximum torque limitation, adjust the running phase of the target motor according to the optimal conduction phase number, and complete the control of the target motor.

[0135] In addition, the computer program in the memory 830 described above can be realized in the form of a software function unit and sold or used as an independent product, and can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application essentially or the part that contributes to the prior art or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various media that can store program codes.

[0136] The device embodiments described above are only schematic, wherein the units illustrated as separate components can or can not be physically separated, and the components illustrated as units can or can not be physical units, i.e., can be located in one place, or can be distributed on a plurality of network units. Part or all of the modules can be selected according to actual needs to achieve the purpose of the present embodiment. Those skilled in the art can understand and implement without creative labor.

[0137] From the above description of the embodiments, those skilled in the art can clearly understand that the embodiments can be realized by means of software and the necessary general hardware platform, and of course can also be realized by hardware. Based on such understanding, the above technical solutions essentially or the part that contributes to the prior art can be embodied in the form of a software product. The computer software product can be stored in a computer readable storage medium, such as a ROM / RAM, a magnetic disk, an optical disk, etc., and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0138] It should be pointed out finally that the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit the same; and although the present application has been described in detail with reference to the foregoing embodiments, it should be appreciated by those skilled in the art that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features thereof can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for optimizing the efficiency of a multiphase motor based on variable conduction mode, characterized in that, include: S1: Determine the target motor, construct the torque expression and determine the number of conducting phases, and determine the maximum torque limit based on the torque expression and the number of conducting phases; S2: Calculate the average copper loss of the current, construct the total copper loss expression through the average copper loss of the current, calculate the effective value of the phase current, and calculate the phase copper loss based on the total copper loss expression and the effective value of the phase current. S3: Construct expressions for odd-phase conduction loss and even-phase conduction loss, and calculate inverter conduction loss based on these expressions. S4: Calculate the inverter switching loss. Obtain the inverter loss through the inverter conduction loss and inverter switching loss. Obtain the total motor loss based on the inverter loss and phase copper loss. S5: Under the constraint of maximum torque limit, the optimal number of conducting phases is obtained through the total motor loss. The operating phase of the target motor is adjusted according to the optimal number of conducting phases to complete the control of the target motor.

2. The method for optimizing the efficiency of a multiphase motor based on a variable conduction mode according to claim 1, characterized in that, Step S1 further includes: S11: Determine the multiphase motor as the target motor, determine the mechanical angular velocity and back EMF amplitude of the target motor, and obtain the torque expression based on the mechanical angular velocity and back EMF amplitude; S12: Determine the number of conducting phases and the maximum allowable current, and substitute the number of conducting phases and the maximum allowable current into the torque expression to obtain the maximum torque limit.

3. The method for optimizing the efficiency of a multiphase motor based on a variable conduction mode according to claim 1, characterized in that, In step S2, the instantaneous copper loss of the current is calculated, the average copper loss of the current is obtained based on the instantaneous copper loss of the current, and the total copper loss expression is constructed through the average copper loss of the current.

4. The method for optimizing the efficiency of a multiphase motor based on a variable conduction mode according to claim 1, characterized in that, In step S2, the effective values ​​of the odd-phase phase current and the even-phase phase current are constructed, and the effective values ​​of the odd-phase phase current and the even-phase phase current are substituted into the total copper loss expression to obtain the phase copper loss.

5. The method for optimizing the efficiency of a multiphase motor based on a variable conduction mode according to claim 1, characterized in that, In step S3, the expression for the odd-numbered phase conduction loss is: in, Let d be the conduction loss in the (n-2)th phase, and d be the duty cycle during conduction. For the IGBT resistor, This represents the phase current amplitude at the (n-2)th phase. This refers to the zero-current on-state voltage drop of the IGBT. The resistance of the diode, denoted as the zero-current forward voltage drop of the diode, and n is the number of phases of the target motor.

6. The method for optimizing the efficiency of a multiphase motor based on a variable conduction mode according to claim 1, characterized in that, In step S3, the expression for the even-numbered phase conduction loss is: in, Let d be the conduction loss in the (n-1)th phase, d be the duty cycle during conduction, and n be the number of phases of the target motor. This refers to the zero-current on-state voltage drop of the IGBT. The resistance of the diode, This is the zero-current forward voltage drop of the diode. For the IGBT resistor, This represents the phase current amplitude at the (n-1)th phase.

7. The method for optimizing the efficiency of a multiphase motor based on a variable conduction mode according to claim 1, characterized in that, In step S4, after obtaining the inverter switching loss, the inverter switching loss is added to the inverter conduction loss to obtain the inverter loss, and the inverter loss is added to the phase copper loss to obtain the total motor loss.

8. The method for optimizing the efficiency of a multiphase motor based on a variable conduction mode according to claim 1, characterized in that, In step S5, the torque at which the total motor loss between adjacent phases is equal is taken as the critical torque, and the critical torque is constrained by the maximum torque limit to obtain the optimal number of conducting phases; The hysteresis width and torque change indication value are determined, and the operating phase of the target motor is adjusted according to the optimal number of conducting phases, the torque change indication value, and the hysteresis width.

9. A multiphase motor efficiency optimization system based on variable conduction mode, used to execute the multiphase motor efficiency optimization method based on variable conduction mode as described in any one of claims 1 to 8, characterized in that, include: Maximum torque limit module: used to determine the target motor, construct the torque expression and determine the number of conducting phases, and determine the maximum torque limit based on the torque expression and the number of conducting phases; Phase copper loss module: used to calculate the average copper loss of current, construct the total copper loss expression through the average copper loss of current, calculate the effective value of phase current, and calculate the phase copper loss based on the total copper loss expression and the effective value of phase current; Inverter conduction loss module: Constructs expressions for odd-phase conduction loss and even-phase conduction loss, and calculates inverter conduction loss based on these expressions; Motor total loss module: used to calculate inverter switching losses. Inverter losses are obtained through inverter conduction losses and inverter switching losses. The total motor loss is obtained based on inverter losses and phase copper losses. Motor control module: Used to obtain the optimal number of conducting phases by the total motor loss under the constraint of maximum torque limit, and adjust the running phase of the target motor according to the optimal number of conducting phases to complete the control of the target motor.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the multiphase motor efficiency optimization method based on variable conduction mode as described in any one of claims 1 to 8.

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