A method and system for smooth transition in the field-weakening transition region of a permanent magnet synchronous motor based on adaptive reduction of reference voltage

Abstract

The application provides a permanent magnet synchronous motor weak magnetic transition area smooth transition method and system based on a reference voltage adaptive reduction, and belongs to the field of permanent magnet synchronous motor control. The method solves the problem of torque fluctuation caused by voltage overshoot in the existing voltage closed-loop weak magnetic control with a fixed reference voltage. The method comprises the following steps: obtaining a theoretical maximum torque according to a preset current limit value by simultaneously solving a torque equation and a current constraint equation; calculating torque ratio parameters and speed ratio parameters in real time; calculating a reference voltage adaptive coefficient based on an adaptive smooth transition algorithm; multiplying the adaptive coefficient by the inscribed circle voltage of an inverter to dynamically adjust the reference value of the voltage closed loop, so that smooth control of the weak magnetic transition area is realized. The method is mainly used in the fields of electric aircrafts, electric vehicles and robots.

Description

Technical Field

[0001] This invention belongs to the field of permanent magnet synchronous motor control, and in particular relates to a smooth transition method for the field weakening transition zone of a permanent magnet synchronous motor based on adaptive reduction of reference voltage. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs), with their high efficiency, high power density, and excellent dynamic performance, have become core power devices in high-end applications such as electric aircraft, electric vehicles, and industrial robots. However, their speed range is limited by back electromotive force characteristics, requiring field weakening control to achieve a wide range of operation above the base speed. Currently, the mainstream field weakening control scheme is the field weakening control method based on voltage amplitude closed loop. Figure 1 This design utilizes a classic voltage-closed-loop field-weakening framework, adding a voltage loop to the existing current and speed loops. When using SVPWM for inverter control, the reference value for the voltage loop is the amplitude of the inscribed circle of the inverter's DC bus voltage. This difference between the voltage loop value and the actual voltage vector amplitude is then used by a PI regulator to output the d-axis current reference value. By fully utilizing the inverter's voltage limitations, the torque capability of the field-weakening region is enhanced, thus increasing the rotational speed.

[0003] Figure 2 This is a typical field weakening waveform of a motor accelerating from a standstill, where u s The magnitude of the actual voltage vector, u s,ref For the voltage vector reference value, u s,ref It is set to a constant (inscribed circle voltage). Because the upper limit of the voltage loop output is clamped to zero, when the motor accelerates from a standstill, u... s Gradually increase, the voltage loop output becomes zero, until u s First time surpassing u s,ref At this point, the voltage loop begins to output a negative d-axis current reference value i. d,ref If u s Greater than u s,ref i d,ref It will decrease further; if u s Less than u s,ref negative i d,ref It will contract until it reaches a steady state. When the motor accelerates from a standstill into the field weakening region, the traditional voltage-closed-loop field weakening control system with a fixed reference voltage has the following problem: because the upper limit of the voltage loop output is zero, only u... s First time surpassing u s,ref The voltage closed loop only starts working at this time. Therefore, when the motor accelerates from a standstill to the field weakening region, voltage overshoot will always exist, which will further cause torque fluctuations and thus worsen the dynamic response. Summary of the Invention

[0004] In view of this, the present invention aims to propose a method and system for smooth transition in the field weakening transition zone of a permanent magnet synchronous motor based on adaptive reduction of reference voltage, so as to solve the problem of voltage overshoot and torque fluctuation caused by existing voltage closed-loop field weakening control with fixed reference voltage.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for smooth transition in the field weakening transition region of a permanent magnet synchronous motor based on adaptive reduction of reference voltage, the method comprising:

[0007] Step 1: Based on the preset current limit value i s,lim The theoretical maximum torque T is obtained by looking up a table after solving the torque equation and the current constraint equation simultaneously. e,max ;

[0008] Step 2: Calculate the torque ratio parameter ρ and speed ratio parameter μ in real time;

[0009] Step 3: Calculate the adaptive coefficient λ of the reference voltage based on the adaptive smooth transition algorithm;

[0010] Step 4: Multiply the inverter's inscribed circle voltage by the adaptive coefficient λ to dynamically adjust the voltage closed-loop reference value u. s,ref This enables smooth control of the weak magnetic transition region.

[0011] Furthermore, a preferred method is proposed, wherein step 1 obtains the theoretical maximum torque value by looking up a table using the simultaneous torque equation and current constraint equation, including:

[0012]

[0013] Where, p n For extreme logarithms; i d Let i be the d-axis current. q L is the q-axis current; d For the d-axis inductance, L q For q-axis inductance, ψ f It is a permanent magnet flux linkage.

[0014] Furthermore, a preferred embodiment is proposed, wherein step 2 includes:

[0015]

[0016] Where, ω e It is the electric angular velocity of the motor; ω e,ref This is the reference value for the motor's speed; T e It is electromagnetic torque.

[0017] Furthermore, a preferred embodiment is proposed, wherein the electromagnetic torque T eIt is directly obtained from the speed ring output.

[0018] Furthermore, a preferred embodiment is proposed, wherein step 3 includes:

[0019] λ=-ρ(μ-1) 2 +1.

[0020] Furthermore, a preferred embodiment is proposed, wherein the reference voltage adaptive coefficient λ satisfies 0≤λ≤1.

[0021] Furthermore, a preferred embodiment is proposed, wherein step 4 includes:

[0022]

[0023] Among them, u dc It is the DC bus voltage of the inverter.

[0024] Based on the same inventive concept, this invention also proposes a smooth transition system for the field weakening transition region of a permanent magnet synchronous motor based on adaptive reduction of reference voltage, the system comprising:

[0025] The maximum torque acquisition unit is used to obtain the maximum torque value based on a preset current limit value i. s,lim The theoretical maximum torque T is obtained by looking up a table after solving the torque equation and the current constraint equation simultaneously. e,max ;

[0026] The calculation unit is used to calculate the torque ratio parameter ρ and the speed ratio parameter μ in real time;

[0027] The reference voltage adaptive coefficient acquisition unit is used to calculate the reference voltage adaptive coefficient λ based on the adaptive smooth transition algorithm.

[0028] The dynamic adjustment unit is used to multiply the inverter's inscribed circle voltage by the adaptive coefficient λ to dynamically adjust the reference value u of the voltage closed loop. s,ref This enables smooth control of the weak magnetic transition region.

[0029] Based on the same inventive concept, the present invention also proposes a computer device, including a memory and a processor, wherein the memory stores a computer program, and when the processor runs the computer program stored in the memory, the processor executes a smooth transition method for the field weakening transition zone of a permanent magnet synchronous motor based on adaptive reduction of reference voltage as described in any one of the preceding claims.

[0030] Based on the same inventive concept, the present invention also proposes a computer-readable storage medium storing a computer program, which, when executed by a processor, performs the steps of a smooth transition method for the field weakening transition zone of a permanent magnet synchronous motor based on adaptive reduction of reference voltage as described above.

[0031] Compared with the prior art, the beneficial effects of the present invention are:

[0032] 1. The proposed smooth transition method for the field weakening transition zone of a permanent magnet synchronous motor introduces dynamic parameters of speed ratio (μ) and torque ratio (ρ) to generate an adaptive coefficient λ for real-time correction of the voltage reference value. During acceleration, when the actual speed does not reach the reference value (i.e., μ≠1), λ varies with ρ and (μ-1). 2 The product term is dynamically decayed, actively reducing the voltage closed-loop reference value, causing the voltage loop controller to exit saturation state earlier. Experimental results show that this method can suppress dynamic voltage overshoot to within 5% of the DC bus voltage (compared to 10%-15% for traditional methods), effectively optimizing voltage trajectory tracking performance.

[0033] 2. The smooth transition method for the field weakening transition zone of permanent magnet synchronous motors proposed in this invention directly reduces the abrupt change in d-axis current by suppressing voltage overshoot. Since torque output is strongly correlated with q-axis current, the smooth adjustment of d-axis current during dynamic processes reduces the amplitude of electromagnetic torque fluctuations by 60%-70%, significantly improving the operational stability of the high-speed field weakening zone, and is particularly suitable for precision drive scenarios sensitive to torque pulsation.

[0034] 3. In the smooth transition method for the field weakening transition zone of the permanent magnet synchronous motor proposed in this invention, the calculation of the adaptive coefficient λ depends only on the directly measurable electrical angular velocity and the torque command output by the speed loop. It does not require online identification or calibration of motor parameters, thus avoiding the problem of reduced control performance caused by parameter temperature drift, aging or magnetic saturation in traditional methods, and significantly improving the system's tolerance to changes in motor parameters.

[0035] 4. The smooth transition method for the field weakening transition zone of the permanent magnet synchronous motor proposed in this invention ensures that λ automatically recovers to 1 under steady-state conditions (μ=1), guaranteeing that the voltage reference value returns to the voltage limit of the inscribed circle and maintaining the steady-state torque output capability of the traditional method. During the dynamic transition phase, the gradual reduction characteristic of λ ensures a smooth transition of the reference voltage, avoids secondary oscillations caused by step adjustment, and achieves a natural connection in the field weakening zone switching process.

[0036] 5. The method proposed in this invention does not require additional sensors or complex parameter identification algorithms; performance improvement can be achieved simply by improving the voltage loop reference value generation logic. This method can be directly embedded into existing voltage closed-loop field weakening control frameworks and is compatible with mainstream SVPWM modulation strategies. Attached Figure Description

[0037] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0038] Figure 1 The classic voltage closed-loop field weakening framework described in the background of this invention;

[0039] Figure 2 This is a schematic diagram of the field weakening operation waveform of the motor accelerating from a standstill, as described in the background art of this invention.

[0040] Figure 3 This is a control block diagram of the smooth transition strategy for the field weakening transition region based on adaptive reduction of reference voltage as described in this invention.

[0041] Figure 4 This is a schematic diagram of the adaptive reference voltage progressive reduction described in this invention;

[0042] Figure 5 This is a schematic diagram of the optimized voltage waveform in the magnetic weakening transition region described in this invention;

[0043] Figure 6 This is a schematic diagram of the voltage trajectory comparison experiment results described in this invention;

[0044] Figure 7 This is a schematic diagram of the torque fluctuation comparison experiment results described in this invention. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other, and the described embodiments are only some embodiments of the present invention, not all embodiments.

[0046] Implementation Method 1: A method for smooth transition in the field weakening transition region of a permanent magnet synchronous motor based on adaptive reduction of reference voltage, as described in this implementation method, includes:

[0047] Step 1: Based on the preset current limit value i s,lim The theoretical maximum torque T is obtained by looking up a table after solving the torque equation and the current constraint equation simultaneously. e,max ;

[0048] Step 2: Calculate the torque ratio parameter ρ and speed ratio parameter μ in real time;

[0049] Step 3: Calculate the adaptive coefficient λ of the reference voltage based on the adaptive smooth transition algorithm;

[0050] Step 4: Multiply the inverter's inscribed circle voltage by the adaptive coefficient λ to dynamically adjust the voltage closed-loop reference value u. s,ref This enables smooth control of the weak magnetic transition region.

[0051] This embodiment proposes a smooth transition method for the field weakening transition zone of a permanent magnet synchronous motor (PMSM) based on adaptive reduction of the reference voltage. This method achieves a smooth transition from acceleration to field weakening operation of the PMSM from a stationary state, and the reference value of its voltage closed-loop can be adjusted according to actual operating conditions. To determine the adaptive coefficient of the reference voltage, an adaptive reference voltage gradual reduction strategy is designed. The proposed method can correct the reference voltage using only directly obtainable torque and speed information without introducing additional control parameters. This scheme allows the voltage closed-loop controller in the field weakening transition zone to exit saturation state earlier, thereby suppressing voltage overshoot and torque fluctuations during dynamic processes.

[0052] Implementation Method Two: This implementation method further defines the smooth transition method for the field weakening transition zone of a permanent magnet synchronous motor based on adaptive reduction of reference voltage described in Implementation Method One. Step 1 obtains the theoretical maximum torque value by looking up a table using the simultaneous torque equation and current constraint equation, including:

[0053]

[0054] Where, p n For extreme logarithms; i d Let i be the d-axis current. q L is the q-axis current; d For the d-axis inductance, L q For q-axis inductance, ψ f It is a permanent magnet flux linkage.

[0055] Implementation Method 3: This implementation method further defines the smooth transition method for the field weakening transition region of a permanent magnet synchronous motor based on adaptive reduction of reference voltage described in Implementation Method 1. Step 2 includes:

[0056]

[0057] Where, ω e It is the electric angular velocity of the motor; ω e,ref This is the reference value for the motor's speed; T e It is electromagnetic torque.

[0058] This implementation introduces reference values ​​for electric angular velocity and motor speed to further reflect the real-time impact of motor speed changes on the field weakening transition region. This allows for a more accurate consideration of the difference between the actual and desired motor operating states when calculating torque ratio and speed ratio parameters, thereby enabling more precise adjustment of reference voltage and current limits and further optimization of the motor's transition process.

[0059] In the field weakening transition region, changes in motor speed and electromagnetic torque can lead to voltage overshoot and torque fluctuations that may occur in traditional methods. This implementation introduces reference values ​​for electrical angular velocity and speed, which better reflects the dynamic behavior of the motor during the transition process. This allows the reference voltage to be adjusted more smoothly according to the actual motor speed during real-time control, thereby more effectively suppressing torque fluctuations and voltage overshoot.

[0060] In this embodiment, by calculating the reference values ​​of the motor's electric angular velocity and rotational speed in real time, as well as their relationship with the electromagnetic torque, dynamic adjustments can be made based on the current operating speed and torque information of the motor. This not only ensures a smooth transition of the motor in the field weakening transition zone, but also helps maintain the motor's stability, avoiding unnecessary fluctuations during acceleration due to improper voltage or torque control, thus improving the overall performance of the motor.

[0061] Implementation Method Four: This implementation method further defines the smooth transition method for the field weakening transition region of a permanent magnet synchronous motor based on adaptive reduction of reference voltage described in Implementation Method Three. The electromagnetic torque T... e It is directly obtained from the speed ring output.

[0062] In this embodiment, due to the electromagnetic torque T e The electromagnetic torque is directly obtained from the speed loop output, which makes the change in electromagnetic torque during the entire transition process respond in real time, allowing for more precise adjustment of the motor's operating state and avoiding the lag or inaccuracy of torque control.

[0063] Implementation Method 5: This implementation method further defines the smooth transition method for the field weakening transition region of a permanent magnet synchronous motor based on adaptive reduction of reference voltage described in Implementation Method 1. Step 3 includes:

[0064] λ=-ρ(μ-1) 2 +1.

[0065] In this embodiment, by adaptively reducing the reference voltage, a smooth transition can be achieved in the field weakening transition region, avoiding the sudden changes or fluctuations that may occur in traditional methods, reducing the instability caused by electromagnetic torque fluctuations during motor operation, and improving the overall stability of the system.

[0066] Implementation Method Six: This implementation method further defines the smooth transition method for the field weakening transition zone of a permanent magnet synchronous motor based on adaptive reduction of reference voltage described in Implementation Method Five. The adaptive reference voltage coefficient λ satisfies 0≤λ≤1.

[0067] In this embodiment, the reference voltage adaptive coefficient λ has three characteristics: (1) the square term (μ-1) 2The existence of λ makes λ symmetric about μ = 1, and μ = 1 holds only when the speed follows its reference value. (2) Multiply by (μ - 1) the torque ratio ρ. 2 , indicating the effect of torque during the field weakening transition. As ρ increases, λ decreases to provide a lower voltage reference. (3) λ is limited to 0 to 1. When λ = 1, it means that the inscribed circle reference voltage is used.

[0068] Implementation Method Seven: This implementation method further defines the smooth transition method for the field weakening transition region of a permanent magnet synchronous motor based on adaptive reduction of reference voltage described in Implementation Method One. Step 4 includes:

[0069]

[0070] Among them, u dc It is the DC bus voltage of the inverter.

[0071] Implementation Method 8: A smooth transition system for the field weakening transition region of a permanent magnet synchronous motor based on adaptive reduction of reference voltage, as described in this implementation method, the system comprising:

[0072] The maximum torque acquisition unit is used to obtain the maximum torque value based on a preset current limit value i. s,lim The theoretical maximum torque T is obtained by looking up a table after solving the torque equation and the current constraint equation simultaneously. e,max ;

[0073] The calculation unit is used to calculate the torque ratio parameter ρ and the speed ratio parameter μ in real time;

[0074] The reference voltage adaptive coefficient acquisition unit is used to calculate the reference voltage adaptive coefficient λ based on the adaptive smooth transition algorithm.

[0075] The dynamic adjustment unit is used to multiply the inverter's inscribed circle voltage by the adaptive coefficient λ to dynamically adjust the reference value u of the voltage closed loop. s,ref This enables smooth control of the weak magnetic transition region.

[0076] Implementation Method Nine: A computer device according to this implementation method includes a memory and a processor. The memory stores a computer program. When the processor runs the computer program stored in the memory, the processor executes a smooth transition method for the field weakening transition zone of a permanent magnet synchronous motor based on adaptive reduction of reference voltage, as described in any one of Implementation Methods One to Seven.

[0077] Implementation Method 10: A computer-readable storage medium according to this implementation method stores a computer program, which, when executed by a processor, performs the steps of a smooth transition method for the field weakening transition zone of a permanent magnet synchronous motor based on adaptive reduction of reference voltage, as described in any one of Implementation Methods 1 to 7.

[0078] Implementation Method 11, see below Figures 3 to 7 This embodiment describes a specific example of the smooth transition method for the field weakening transition region of a permanent magnet synchronous motor based on adaptive reduction of reference voltage described in Embodiment 1. It also serves to explain Embodiments 2 through 7. Specifically:

[0079] Step 1: Based on the set current limit i s,lim The maximum torque T is obtained by looking up the table. e,max .

[0080] Eliminate i by combining the following equations d and i q Get T e,max and i s,lim Relationship:

[0081]

[0082] In the formula: p n For extreme logarithms; i d i q L represents the d-axis and q-axis currents. d L q ψ is the inductance along the d and q axes; f It is a permanent magnet flux linkage.

[0083] Solve T according to the requirements. e,max and i s,lim The relationship is stored in the lookup table, actually T e,max (i s,lim The function is monotonically increasing. In practice, the current limit i is set according to the actual current. s,lim The theoretical maximum torque T is obtained by looking up the table. e,max .

[0084] Step 2: Calculate the two parameters ρ and μ required for the adaptive smooth transition controller based on the control input.

[0085] In this step, ρ and μ are calculated based on the torque and speed information, respectively. In this invention, the electromagnetic torque T... e Obtained from the speed ring output (see) Figure 3 ), speed feedback value ω e Since the values ​​are obtained from samples taken by the rotary encoder, they can be considered as known quantities. Therefore, the calculation process for ρ and μ can be written as follows:

[0086]

[0087] In the formula: ω e It is the electric angular velocity of the motor; ω e,ref This is the reference value for the motor's speed; T e It is electromagnetic torque; T e,max The theoretical maximum torque (and i) s,lim (Related), obtained from step 1.

[0088] Step 3: Calculate the adaptive coefficient λ of the reference voltage using the adaptive smooth transition algorithm.

[0089] The method for calculating the reference voltage adaptive coefficient λ is as follows:

[0090] λ=-ρ(μ-1) 2 +1 (3)

[0091] Figure 4 The diagram illustrates the asymptotic reduction of the adaptive reference voltage, showing the curves of λ versus μ and ρ. The adaptive reference voltage coefficient λ has three characteristics: (1) the square term (μ-1) 2 The existence of λ makes λ symmetric about μ = 1, and μ = 1 holds only when the speed follows its reference value. (2) Multiply by (μ - 1) the torque ratio ρ. 2 , indicating the effect of torque during the field weakening transition. As ρ increases, λ decreases to provide a lower voltage reference. (3) λ is limited to 0 to 1. When λ = 1, it means that the inscribed circle reference voltage is used.

[0092] It should be noted that the reference voltage always decreases except in steady state (μ = 1). In fact, according to the proposed voltage adaptive reduction method, as the rotational speed approaches the steady-state value, the voltage reference always asymptotically approaches the voltage limit. By dynamically adjusting the reference voltage based on the voltage adaptive coefficient, a smooth transition control strategy can be obtained.

[0093] Step 4: Modify the reference value u of the voltage closed loop. s,ref .

[0094] Multiplying the voltage of the inscribed circle by the voltage adaptive coefficient yields the final closed-loop voltage reference value u. s,ref :

[0095]

[0096] In the formula: u dc It is the DC bus voltage of the inverter.

[0097] The above solution can resolve the voltage overshoot problem of a permanent magnet synchronous motor accelerating from a standstill to the field weakening region. The optimized voltage waveform in the field weakening transition region is shown below. Figure 5As shown, this is achieved by prematurely exiting saturation of the field weakening regulator during the dynamic process.

[0098] The control method proposed in this invention was experimentally verified, specifically using a three-phase permanent magnet synchronous motor on the experimental platform. The motor had a rated voltage of 380V, a rated power of 2.2kW, and a base speed of 2000rpm (1.0pu). Figure 6 and Figure 7 The experimental results comparing the dynamic voltage trajectory and torque fluctuation of the traditional method and the proposed method are presented respectively. The motors were accelerated from rest in both cases. The speed step signals were set to 1.0 pu, 1.1 pu, 1.2 pu, 1.3 pu, 1.4 pu, and 1.5 pu, respectively. Figure 6 Compared with traditional methods, the proposed method significantly suppresses voltage overshoot. With voltage overshoot suppressed, torque ripple is also correspondingly suppressed. Figure 7 The experimental results show that, compared with traditional methods, the dynamic torque fluctuation of the method proposed in this invention is reduced by 60% to 70%, which further verifies the effectiveness of the proposed adaptive reduction method of reference voltage in suppressing voltage overshoot and reducing torque fluctuation during dynamic acceleration.

[0099] Those skilled in the art will understand that embodiments of this disclosure can be provided as methods, systems, or computer program products. Therefore, this disclosure can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this disclosure can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0100] This disclosure is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this disclosure. It will 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 computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create a machine for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1 The computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to operate in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0101] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this disclosure and not to limit its protection scope. Although this disclosure has been described in detail with reference to the above embodiments, those skilled in the art should understand that after reading this disclosure, they can still make various changes, modifications or equivalent substitutions to the specific implementation of the invention, but these changes, modifications or equivalent substitutions are all within the protection scope of the published pending claims.

Claims

1. A method for smooth transition in the field weakening transition region of a permanent magnet synchronous motor based on adaptive reduction of reference voltage, characterized in that, The method includes: Step 1: According to the preset current limit value i s,lim The theoretical maximum torque value is obtained by looking up a table after solving the torque equation and the current constraint equation simultaneously. T e,max ; Step 2: Calculate torque ratio parameters in real time ρ and speed ratio parameter μ ; Step 3: Calculate the adaptive coefficient of the reference voltage based on the adaptive smooth transition algorithm. λ ; Step 4: Compare the inverter's inscribed circle voltage with the adaptive coefficient. λ Multiplication, dynamically adjusting the reference value of the voltage closed loop. u s,ref To achieve smooth control of the weak magnetic transition region; Step 1 involves obtaining the theoretical maximum torque by simultaneously solving the torque equations and the current constraint equations and then looking up a table. This includes: in, p n It is the extreme logarithm; i d for d shaft current, i q for q shaft current; L d for d Shaft inductor, L q for q Shaft inductor, ψ f For permanent magnet flux linkage; Step 2 includes: in, ω e It is the electric angular velocity of the motor; ω e,ref This is a reference value for the motor's speed; T e It is electromagnetic torque; Step 3 includes: 。 2. The method for smooth transition in the field weakening transition zone of a permanent magnet synchronous motor based on adaptive reduction of reference voltage according to claim 1, characterized in that, The electromagnetic torque T e It is directly obtained from the speed ring output.

3. The method for smooth transition in the field weakening transition zone of a permanent magnet synchronous motor based on adaptive reduction of reference voltage according to claim 1, characterized in that, The reference voltage adaptive coefficient λ Satisfy 0≤ λ≤ 1.

4. The method for smooth transition in the field weakening transition zone of a permanent magnet synchronous motor based on adaptive reduction of reference voltage according to claim 1, characterized in that, Step 4 includes: ， in, u dc It is the DC bus voltage of the inverter.

5. A smooth transition system for the field weakening transition region of a permanent magnet synchronous motor based on adaptive reduction of reference voltage, characterized in that, The system is implemented based on the method described in claim 1, and the system comprises: The maximum torque acquisition unit is used to obtain the maximum torque value based on a preset current limit value. i s,lim The theoretical maximum torque value is obtained by looking up a table after solving the torque equation and the current constraint equation simultaneously. T e,max ; The calculation unit is used to calculate the torque ratio parameter in real time. ρ and speed ratio parameter μ ; The reference voltage adaptive coefficient acquisition unit is used to calculate the reference voltage adaptive coefficient based on the adaptive smooth transition algorithm. λ ; The dynamic adjustment unit is used to adjust the voltage of the inverter's inscribed circle relative to the adaptive coefficient. λ Multiplication, dynamically adjusting the reference value of the voltage closed loop. u s,ref This enables smooth control of the weak magnetic transition region.

6. A computer device, characterized in that: It includes a memory and a processor, wherein the memory stores a computer program, and when the processor runs the computer program stored in the memory, the processor executes a smooth transition method for the field weakening transition zone of a permanent magnet synchronous motor based on adaptive reduction of reference voltage as described in any one of claims 1-4.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, performs the steps of a smooth transition method for the field weakening transition zone of a permanent magnet synchronous motor based on adaptive reduction of reference voltage, as described in any one of claims 1-4.

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