A dynamic performance enhanced permanent magnet synchronous motor voltage closed loop flux weakening control method

Abstract

The application discloses a dynamic performance enhanced permanent magnet synchronous motor voltage closed loop field weakening control algorithm, and relates to a permanent magnet synchronous motor voltage closed loop field weakening control algorithm. The application is to overcome the shortcomings of the traditional permanent magnet synchronous motor field weakening control method. The steps of the application comprise the following steps: step 1, calculating a dynamic performance enhanced lookup table and constructing a voltage closed loop field weakening framework; step 2, calculating a weight factor K in a smooth transition process; and step 3, synthesizing a field weakening reference output of a voltage closed loop method and a field weakening reference output of a lookup table method according to the weight factor K. The application belongs to the technical field of permanent magnet synchronous motor voltage closed loop field weakening control.

Description

Technical Field

[0001] The invention relates to a voltage closed-loop magnetic weakening control method for a permanent magnet synchronous motor, belonging to the technical field of voltage closed-loop magnetic weakening control for permanent magnet synchronous motors. Background Art

[0002] Permanent magnet synchronous motors require field weakening control when running above base speed. Traditional methods for obtaining field weakening control reference values, such as the voltage closed-loop method and the lookup table method, cannot achieve both high speed and strong robustness, resulting in a loss of dynamic or steady-state performance.

[0003] like Figure 1 As shown in the figure, the traditional voltage closed-loop weak magnetic control framework introduces a voltage loop on the basis of the double closed-loop; there are two problems with the traditional permanent magnet synchronous motor weak magnetic control method: First, for the voltage closed-loop method, the voltage closed-loop PI regulator will output a negative value only when the stator voltage amplitude exceeds the voltage limit. d shaft current, which will inevitably lead to overshoot of the voltage vector amplitude in the dynamic process; secondly, for the lookup table method, the set value is greatly affected by parameter changes. If the motor parameters are inaccurate, the steady-state operating point position of the weak magnetic field of the lookup table method will deviate from the actual one. Summary of the Invention

[0004] In order to solve the shortcomings of the traditional permanent magnet synchronous motor field weakening control method, the present invention proposes a permanent magnet synchronous motor voltage closed-loop field weakening control method with enhanced dynamic performance.

[0005] The technical solution adopted by the present invention to solve the above problems is: the steps of the present invention include:

[0006] Step 1: Calculate the dynamic performance enhancement lookup table and build a voltage closed-loop magnetic weakening framework;

[0007] Step 2: Calculate the weight factor during the smooth transition process ;

[0008] Step 3: According to the weight factor Combined voltage closed-loop method for field weakening reference output and lookup table method for field weakening reference output.

[0009] Furthermore, step 1 specifically includes:

[0010] The dynamic performance enhancement lookup table is calculated according to the permanent magnet synchronous motor's weakening operating point, and a weakening control framework is established.

[0011] Furthermore, the weight factor in step 2 The minimum value of is 1. K =1 indicates steady state, K >1 means dynamic, weight factor The calculation formula is:

[0012] (1),

[0013] In formula (1), oh e,error is the speed reference value oh e,ref and feedback value oh e The error, d It is the expected speed control accuracy set by humans. oh e,error > d · oh e,ref When oh e,error < d · oh e,ref , indicating that the system is in steady state.

[0014] Furthermore, the final output in step 3 is i d,ref for:

[0015] (2),

[0016] In formula (2), i d,ref1 Represents the output of the voltage closed-loop method, i d,ref2 Represents the output of the lookup table method. When the speed or load changes, K Increased to its maximum value, i d,ref Depend on i d,ref2 Dominate, over time, K Gradually decrease to 1, i d,ref2 The weight gradually becomes 0, achieving i d,ref1 and i d,ref2 Adaptive smooth transition between.

[0017] The beneficial effects of the present invention are:

[0018] 1. The present invention combines the advantages of the table lookup method and the voltage closed-loop method, and optimizes the dynamic current trajectory of the traditional voltage closed-loop weak magnetic field through an adaptive trade-off algorithm;

[0019] 2. The present invention suppresses current overshoot in the dynamic process while ensuring the robustness of steady-state parameters;

[0020] 3. The present invention optimizes the dynamic current trajectory of the traditional voltage closed-loop method and solves the parameter sensitivity problem of the lookup table method through the voltage closed-loop method. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the traditional permanent magnet synchronous motor voltage closed-loop field weakening control framework;

[0022] Figure 2 is a schematic diagram of the present invention;

[0023] Figure 3 This is a schematic diagram of the dynamic current trajectory comparison experimental results;

[0024] Figure 4 It is a schematic diagram of the step acceleration experiment results when the parameters are mismatched;

[0025] Figure 5 This is a schematic diagram of the test results of sudden load when the parameters are mismatched. DETAILED DESCRIPTION

[0026] Specific implementation method 1: Figure 2 As shown, a voltage closed-loop field weakening control method for a permanent magnet synchronous motor with enhanced dynamic performance includes the following specific steps:

[0027] Step 1: Calculate the dynamic performance enhancement lookup table and build a voltage closed-loop magnetic weakening framework;

[0028] Calculate the dynamic performance enhancement lookup table based on the permanent magnet synchronous motor's field weakening operating point and build a field weakening control framework;

[0029] Step 2: Calculate the weight factor during the smooth transition process ;

[0030] Weighting Factor The minimum value of is 1. K =1 indicates steady state, K >1 means dynamic, weight factor The calculation formula is:

[0031] (1),

[0032] In formula (1), oh e,error is the speed reference value oh e,ref and feedback value oh e The error, d It is the expected speed control accuracy set by humans. oh e,error > d · oh e,refWhen oh e,error < d · oh e,ref When , the system is in steady state;

[0033] Step 3: According to the weight factor Integrated voltage closed-loop method for weakening magnetic reference output and lookup table method for weakening magnetic reference output;

[0034] The final output i d,ref for:

[0035] (2),

[0036] In formula (2), i d,ref1 Represents the output of the voltage closed-loop method, i d,ref2 Represents the output of the lookup table method. When the speed or load changes, K Increased to its maximum value, i d,ref Depend on i d,ref2 Dominate, over time, K Gradually decrease to 1, i d,ref2 The weight gradually becomes 0, achieving i d,ref1 and i d,ref2 Adaptive smooth transition between.

[0037] Experimental verification

[0038] The present invention is used to conduct an experimental verification on an actual three-phase permanent magnet synchronous motor towing test platform. The motor used in the experiment has a rated voltage of 380V and a rated power of 2.2kW. Figure 3 As shown, the speed step experiment refers to the motor speed suddenly increasing from the base speed to 1.5 times the base speed and then suddenly decreasing to the base speed. The load experiment refers to suddenly adding 50% of the rated load at 1.2 times the base speed and then removing the load. According to the experimental results, the area enclosed by the current trajectory of the voltage closed-loop method is the largest, which means that its dynamic response is the worst, while the area of ​​the lookup table method is the smallest, which means better dynamic performance. The present invention enhances the dynamic performance of the traditional voltage closed-loop method and makes it have a dynamic current response similar to that of the lookup table method.

[0039] In order to further explain the parameter robustness of the present invention, parameter mismatch experiments were conducted, such as Figure 4 and Figure 5 As shown in the figure, it can be seen that in steady state, parameter changes will not affect the voltage closed-loop method and the proposed method.d shaft current reference, but it will deteriorate the performance of the lookup table method, especially in load experiments; in addition, since the speed adaptive voltage regulator is related to the inductance parameters, the dynamic performance of the voltage closed-loop method will also be affected by parameter mismatch; it can be seen from the experimental results that the present invention is least affected by parameter changes.

[0040] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with the present profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical content disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent replacement and improvement of the above embodiments made according to the technical essence of the present invention, within the spirit and principles of the present invention, without departing from the content of the technical solution of the present invention, shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for voltage closed-loop field weakening control of a permanent magnet synchronous motor with enhanced dynamic performance, characterized in that: The specific steps include: Step 1: Calculate the dynamic performance enhancement lookup table and build a voltage closed-loop magnetic weakening framework; Step 2: Calculate the weight factor during the smooth transition process ; Weight factor The minimum value of is 1. K =1 indicates steady state, K >1 means dynamic, weight factor The calculation formula is: （1）， In formula (1), ω e,error is the speed reference value ω e,ref and feedback value ω e The error, δ It is the expected speed control accuracy set by humans. ω e,error > δ · ω e,ref When ω e,error < δ · ω e,ref When , the system is in steady state; Step 3: According to the weight factor The weak magnetic reference output of the integrated voltage closed loop method and the weak magnetic reference output of the lookup table method; the final output i d,ref for: （2）， In formula (2), i d,ref1 Represents the output of the voltage closed-loop method, i d,ref2 Represents the output of the lookup table method. When the speed or load changes, K Increased to its maximum value, i d,ref Depend on i d,ref2 Dominate, over time, K Gradually decrease to 1, i d,ref2 The weight gradually becomes 0, achieving i d,ref1 and i d,ref2 Adaptive smooth transition between.

2. A method for controlling a permanent magnet synchronous motor with closed-loop voltage weakening with enhanced dynamic performance according to claim 1, characterized in that: Step 1 specifically includes: The dynamic performance enhancement lookup table is calculated according to the permanent magnet synchronous motor's weakening operating point, and a weakening control framework is established.

Images