Permanent magnet synchronous motor control method based on pulsating high-frequency voltage injection method

Abstract

The invention belongs to the field of permanent magnet synchronous motor control, and particularly relates to a permanent magnet synchronous motor control method based on a pulsating high-frequency voltage injection method, which comprises the following steps: establishing a mathematical model of a PMSM under a three-phase coordinate system, and obtaining a mathematical model under a two-phase rotating coordinate system through Clark transformation and Park transformation. At the moment, a pulsating high-frequency voltage injection method is introduced into an error angle delta theta of the rotor position, a high-frequency voltage signal is injected into an estimated direct-axis coordinate system, a high-frequency current signal is extracted through a band-pass filter, a high-frequency current equation responded by an estimated direct axis is obtained, the high-frequency current equation is multiplied by a modulation signal with the same frequency, f (delta theta) is obtained through a low-pass filter, and an estimated direct-axis coordinate system is obtained; when the position error of the rotor is small enough and f (delta theta) is equal to 0, delta theta is equal to 0. At the moment, the amplitude f (delta theta) = 0 is introduced into the PI controller, the PI controller outputs the estimated rotating speed, and the electrical angle is predicted in an algorithm mode, so that a traditional Hall sensor is replaced.

Description

Technical Field

[0001] The invention belongs to the field of permanent magnet synchronous motor control, and in particular relates to a permanent magnet synchronous motor control method based on a pulse high frequency voltage injection method. Background Art

[0002] Permanent Magnet Synchronous Motor (PMSM) has a relatively simple structure, high power density, strong reliability and high efficiency, and has been widely used in the field of motor control. The most commonly used control method for permanent magnet synchronous motors is vector control. The core of this control method is to perform Clark transformation and Park transformation on voltage and current, and decompose the three-phase current into quadrature-axis and direct-axis currents in a two-phase rotating coordinate system. In order to achieve vector control, the electrical angle of the rotor needs to be obtained. The traditional method is to use Hall sensors to detect the electrical angle of the rotor in real time. However, in harsh environments, the effect of Hall sensors may be greatly reduced. At the same time, in order to save costs and reduce size, the current research focus is to use algorithms to predict the electrical angle, thereby replacing traditional Hall sensors. Therefore, which algorithm to choose to achieve this goal and how to simplify the algorithm as much as possible has become one of the current research hotspots in the field of motor control. Summary of the invention

[0003] In order to solve the above problems in the related art, the present invention provides a permanent magnet synchronous motor control method based on a pulse high frequency voltage injection method.

[0004] The present invention adopts the following technical solution:

[0005] A permanent magnet synchronous motor control method based on a pulse high frequency voltage injection method comprises the following steps:

[0006] 1) Establish the voltage equation of the three-phase coordinate system of the permanent magnet synchronous motor PMSM;

[0007] 2) The voltage equation of the permanent magnet synchronous motor in the three-phase coordinate system is simplified to the voltage equation in the αβ two-phase stationary coordinate system through Clark transformation;

[0008] 3) The voltage equation of the permanent magnet synchronous motor in the two-phase stationary coordinate system is simplified to the voltage equation in the dq two-phase rotating coordinate system through Park transformation;

[0009] 4) Simplify the voltage equation in the dq two-phase rotating coordinate system into another form with the current derivative as the left-hand term, and obtain the mathematical model of the permanent magnet synchronous motor in the dq two-phase rotating coordinate system;

[0010] 5) Obtain the conversion relationship between the estimated voltage and current of the permanent magnet synchronous motor and the actual voltage and current in the dq two-phase rotating coordinate system through the coordinate relationship diagram;

[0011] 6) Combining the mathematical model of the permanent magnet synchronous motor in the dq two-phase rotating coordinate system, the estimated voltage and current of the permanent magnet synchronous motor, and the conversion relationship between the actual voltage and current, a conversion relationship between the estimated value of the permanent magnet synchronous motor current and the estimated value of the voltage in the two-phase rotating coordinate system is obtained with the derivative of the estimated current as the left term;

[0012] 7) Substituting the average inductance formula on the AC and DC axes and the semi-difference inductance formula on the AC and DC axes into the conversion relationship between the estimated value of the permanent magnet synchronous motor current and the estimated value of the voltage in the two-phase rotating coordinate system with the derivative of the estimated current as the left term, another form of conversion relationship is obtained;

[0013] 8) Inject a high-frequency voltage signal into the estimated direct axis coordinate system and solve the corresponding current relationship;

[0014] 9) extracting the high-frequency current equation to which the estimated direct axis responds from the current relationship, the high-frequency current equation containing the information of Δθ;

[0015] 10) The quadrature-axis current obtained by Park transformation in the system is passed through a bandpass filter to extract the high-frequency current signal, the high-frequency current signal is multiplied by the modulation signal of the same frequency, and then f(Δθ) is obtained through a low-pass filter. The amplitude of f(Δθ) is half of the high-frequency current signal;

[0016] 11) When the rotor position error is small enough, sin(Δθ) is replaced by Δθ. When f(Δθ) = 0, sin(Δθ) = 0, that is, Δθ = 0, and the actual angle of the rotor is consistent with the estimated angle;

[0017] 12) The amplitude f(Δθ) is passed into the PI controller, which outputs the estimated speed and then performs integration processing to obtain the estimated angle. The estimated angle acts on the coordinate transformation to form a closed-loop system and realize vector control of the permanent magnet synchronous motor.

[0018] Furthermore, the voltage equation of the permanent magnet synchronous motor in the three-phase coordinate system established in step 1) is:

[0019]

[0020] Among them U a , U b , U c are the terminal voltages of the windings respectively; i a 、i b 、i c are the phase currents of the three-phase windings; Ea 、E b 、E c is the back electromotive force of the three-phase winding; R s is the winding phase resistance, and L is the equivalent inductance.

[0021] Furthermore, in step 2), the voltage equation in the three-phase coordinate system is simplified to the voltage equation in the αβ two-phase stationary coordinate system:

[0022]

[0023] Among them, E α 、E β is the back electromotive force; αf is the permanent magnet flux; ω r is the rotor angular velocity; θ is the rotor speed.

[0024] Furthermore, in step 3), the voltage equation in the two-phase stationary coordinate system is simplified to the voltage equation in the dq two-phase rotating coordinate system by Park transformation, and the equation is:

[0025]

[0026] u d is the direct axis voltage, u q is the quadrature axis voltage, R is the resistance value, i d is the direct axis current, i q is the quadrature axis current, L d is the direct-axis inductance, L q is the quadrature-axis inductance, ω e is the angular velocity, ψ f is the permanent magnet flux.

[0027] Furthermore, step 4) simplifies the voltage equation in the dq two-phase rotating coordinate system to:

[0028]

[0029] Furthermore, the conversion relationship between the estimated voltage and current and the actual voltage and current shown in step 5) is:

[0030]

[0031] is the estimated value of the direct axis voltage, is the estimated value of the quadrature axis voltage, is the estimated value of the direct axis current, is the estimated value of the quadrature axis current.

[0032] Furthermore, in step 6), the conversion relationship between the estimated value of the permanent magnet synchronous motor current and the estimated value of the voltage in the two-phase rotating coordinate system with the derivative of the estimated current as the left term is:

[0033]

[0034] Further, in step 7), the average inductance formula on the AC and DC axes and the semi-difference inductance formula on the AC and DC axes are substituted into the conversion relationship between the estimated value of the permanent magnet synchronous motor current and the estimated value of the voltage in the two-phase rotating coordinate system with the derivative of the estimated current as the left term:

[0035]

[0036] L is the average inductance on the AC and DC axes, and ΔL is the semi-differential inductance on the AC and DC axes.

[0037] Furthermore, in step 8), the high-frequency voltage signal injected on the estimated direct axis coordinate system and the corresponding current relationship are solved as follows:

[0038]

[0039] in is the high-frequency voltage signal injected into the estimated direct axis coordinate system, U mh is the estimated voltage amplitude of the direct axis, ω h Estimate the angular velocity of the voltage for the direct axis, is the direct axis current value obtained when the voltage signal is injected into the estimated direct axis coordinate system. It is the quadrature-axis current value solved when the voltage signal is injected into the estimated direct-axis coordinate system.

[0040] Furthermore, in the current relationship in step 9), the high-frequency current equation to which the direct axis responds is estimated to be:

[0041]

[0042] In step 10), the high-frequency current signal is multiplied by the modulation signal of the same frequency, and then the f(Δθ) obtained by the low-pass filter is:

[0043]

[0044] The equivalent substitution formula mentioned in step 11) is approximately:

[0045]

[0046] This method establishes the mathematical model of PMSM in the three-phase coordinate system, and obtains the mathematical model in the two-phase rotating coordinate system through Clark transformation and Park transformation. Because the prediction results are more accurate, it is necessary to make the difference between the estimated rotor position and the actual rotor position as small as possible, or even close to 0. In order to extract the error angle Δθ of the rotor position, the pulse high-frequency voltage injection method is introduced. The high-frequency voltage signal is injected into the estimated direct axis coordinate system, and then the high-frequency current signal is extracted through a bandpass filter to obtain the high-frequency current equation responded by the estimated direct axis. Then, it is multiplied with the modulation signal of the same frequency and passed through a low-pass filter to obtain f(Δθ). When the position error of the rotor is small enough, when f(Δθ)=0, Δθ=0. At this time, the amplitude f(Δθ)=0 is passed into the PI controller, and the PI controller will output the estimated speed, and then the estimated angle is obtained through integration processing. The estimated angle is applied to the coordinate transformation to form a closed-loop system of vector control. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 is an equivalent circuit diagram of a permanent magnet synchronous motor in the prior art of an embodiment of the present invention;

[0048] Figure 2 It is a block diagram of the control principle of a permanent magnet synchronous motor based on a pulse high frequency voltage injection method provided by an embodiment of the present invention;

[0049] Figure 3 is a relationship diagram between a two-phase stationary coordinate system, a two-phase rotating coordinate system and an estimated two-phase rotating coordinate system provided by an embodiment of the present invention;

[0050] Figure 4 Detailed Description of the Invention Embodiments of the present invention provide (a) a motor rotor actual speed and estimated speed error diagram and (b) a motor rotor position error diagram. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0052] The present invention is used for Figure 1 In the permanent magnet synchronous motor equivalent circuit shown in Figure 2 A permanent magnet synchronous motor control method based on a pulse high frequency voltage injection method comprises the following steps:

[0053] 1) Establish the voltage equation of the three-phase coordinate system of the permanent magnet synchronous motor PMSM;

[0054] 2) The voltage equation of the permanent magnet synchronous motor in the three-phase coordinate system is simplified to the voltage equation in the αβ two-phase stationary coordinate system through Clark transformation;

[0055] 3) The voltage equation of the permanent magnet synchronous motor in the two-phase stationary coordinate system is simplified to the voltage equation in the dq two-phase rotating coordinate system through Park transformation;

[0056] 4) Simplify the voltage equation in the dq two-phase rotating coordinate system into another form with the current derivative as the left-hand term, and obtain the mathematical model of the permanent magnet synchronous motor in the dq two-phase rotating coordinate system;

[0057] 5) Obtain the conversion relationship between the estimated voltage and current of the permanent magnet synchronous motor and the actual voltage and current in the dq two-phase rotating coordinate system through the coordinate relationship diagram;

[0058] 6) Combining the mathematical model of the permanent magnet synchronous motor in the dq two-phase rotating coordinate system, the estimated voltage and current of the permanent magnet synchronous motor, and the conversion relationship between the actual voltage and current, a conversion relationship between the estimated value of the permanent magnet synchronous motor current and the estimated value of the voltage in the two-phase rotating coordinate system is obtained with the derivative of the estimated current as the left term;

[0059] 7) Substituting the average inductance formula on the AC and DC axes and the semi-difference inductance formula on the AC and DC axes into the conversion relationship between the estimated value of the permanent magnet synchronous motor current and the estimated value of the voltage in the two-phase rotating coordinate system with the derivative of the estimated current as the left term, another form of conversion relationship is obtained;

[0060] 8) Inject a high-frequency voltage signal into the estimated direct axis coordinate system and solve the corresponding current relationship;

[0061] 9) extracting the high-frequency current equation to which the estimated direct axis responds from the current relationship, the high-frequency current equation containing the information of Δθ;

[0062] 10) The quadrature-axis current obtained by Park transformation in the system is passed through a bandpass filter to extract the high-frequency current signal, the high-frequency current signal is multiplied by the modulation signal of the same frequency, and then f(Δθ) is obtained through a low-pass filter. The amplitude of f(Δθ) is half of the high-frequency current signal;

[0063] 11) When the rotor position error is small enough, sin(Δθ) is replaced by Δθ. When f(Δθ) = 0, sin(Δθ) = 0, that is, Δθ = 0, and the actual angle of the rotor is consistent with the estimated angle;

[0064] 12) The amplitude f(Δθ) is passed into the PI controller, which outputs the estimated speed and then performs integration processing to obtain the estimated angle. The estimated angle acts on the coordinate transformation to form a closed-loop system and realize vector control of the permanent magnet synchronous motor.

[0065] In which, assuming that the three-phase winding of the permanent magnet synchronous motor is symmetrical, and the electromagnetic hysteresis loss and eddy current loss of the permanent magnet synchronous motor are ignored, the voltage equation is:

[0066]

[0067] Among them U a , U b , U c are the terminal voltages of the windings respectively; i a 、i b 、i c are the phase currents of the three-phase windings; E a 、E b 、E c is the back electromotive force of the three-phase winding; R s is the winding phase resistance, and L is the equivalent inductance.

[0068] Among them, the mathematical model of the permanent magnet synchronous motor in the αβ two-phase stationary coordinate system is:

[0069]

[0070] Among them, E α 、E β is the back electromotive force; αf is the permanent magnet flux; ω r is the rotor angular velocity; θ is the rotor speed.

[0071] Among them, the voltage equation of the permanent magnet synchronous motor in the dq two-phase rotating coordinate system is:

[0072]

[0073] Among them, u d is the direct axis voltage, u q is the quadrature axis voltage, R is the resistance value, i d is the direct axis current, i q is the quadrature axis current, L d is the direct-axis inductance, L q is the quadrature-axis inductance, ω e is the angular velocity, ψ f is the permanent magnet flux.

[0074] The voltage equation in the dq two-phase rotating coordinate system is simplified to:

[0075]

[0076] Among them, Figure 3 As shown, in the two-phase rotating coordinate system, the conversion relationship between the estimated voltage, current and the actual voltage, current of the PMSM is:

[0077]

[0078] is the estimated value of the direct axis voltage, is the estimated value of the quadrature axis voltage, is the estimated value of the direct axis current, is the estimated value of the quadrature axis current.

[0079] Among them, combined with the voltage equation in the dq two-phase rotating coordinate system, the conversion relationship between the estimated voltage, current and actual voltage and current of the PMSM, the conversion relationship between the estimated value of the permanent magnet synchronous motor current and the estimated value of the voltage in the two-phase rotating coordinate system with the derivative of the estimated current as the left term can be obtained:

[0080]

[0081] Among them, the conversion relationship between the estimated value of the permanent magnet synchronous motor current and the estimated value of the voltage in the two-phase rotating coordinate system is substituted into the average inductance formula on the AC and DC axes and the semi-differential inductance formula on the AC and DC axes with the derivative of the estimated current as the left term:

[0082]

[0083] L is the average inductance on the AC and DC axes, and ΔL is the semi-differential inductance on the AC and DC axes.

[0084] Among them, the high-frequency voltage signal injected in the estimated direct axis coordinate system and the corresponding current relationship solved are:

[0085]

[0086] in is the high-frequency voltage signal injected into the estimated direct axis coordinate system, U mh is the estimated voltage amplitude of the direct axis, ω h Estimate the angular velocity of the voltage for the direct axis, is the direct axis current value obtained when the voltage signal is injected into the estimated direct axis coordinate system. It is the quadrature-axis current value solved when the voltage signal is injected into the estimated direct-axis coordinate system.

[0087] Among them, the high-frequency current equation that estimates the direct axis response in the current relationship is:

[0088]

[0089] The amplitude of the high-frequency current equation contains the information of Δθ. The quadrature-axis current obtained by Park transformation in the system is passed through a bandpass filter (BPF) to extract the high-frequency current signal. The high-frequency current signal is multiplied by the modulation signal of the same frequency, and finally passed through a low-pass filter (LPF) to obtain f(Δθ). The formula of f(Δθ) is:

[0090]

[0091] When the rotor position error Δθ is small enough to form an equivalent infinitesimal substitution condition, sin(2Δθ) can be replaced by 2Δθ, and the above formula can be approximated as:

[0092]

[0093] When f(Δθ)=0, Δθ=0, and the actual rotor angle is equal to the estimated angle. The amplitude f(Δθ) is passed into the PI controller, and the PI controller will output the estimated speed, and then perform integration processing to obtain the estimated angle. The estimated angle acts on the coordinate transformation to form the entire closed-loop system. When the system reaches a steady state, f(Δθ)=0, then the estimated rotor position is equal to the actual rotor position. After the Park transform, a bandpass filter is passed to extract the high-frequency signal, and then a low-pass filter is passed to obtain f(Δθ).

[0094] Figure 4 As shown, Figure 4(a) is the value of the electrical angle detected by the Hall sensor, and Figure 4(b) is the value of the electrical angle estimated by the algorithm. It can be seen from the figure that the error between the value estimated by the algorithm and the electrical angle value tested by the Hall sensor is within one degree, and the permanent magnet synchronous motor control method based on the pulse high-frequency voltage injection method is effective.

[0095] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A permanent magnet synchronous motor control method based on a pulse high frequency voltage injection method, characterized in that: The following steps are involved: 1) Establish the voltage equation of the three-phase coordinate system of the permanent magnet synchronous motor PMSM; 2) The voltage equation of the permanent magnet synchronous motor in the three-phase coordinate system is simplified to the voltage equation in the αβ two-phase stationary coordinate system through Clark transformation; 3) The voltage equation of the permanent magnet synchronous motor in the two-phase stationary coordinate system is simplified to the voltage equation in the dq two-phase rotating coordinate system through Park transformation; 4) Simplify the voltage equation in the dq two-phase rotating coordinate system into another form with the current derivative as the left-hand term, and obtain the mathematical model of the permanent magnet synchronous motor in the dq two-phase rotating coordinate system; 5) Obtain the conversion relationship between the estimated voltage and current of the permanent magnet synchronous motor and the actual voltage and current in the dq two-phase rotating coordinate system through the coordinate relationship diagram; 6) Combining the mathematical model of the permanent magnet synchronous motor in the dq two-phase rotating coordinate system, the estimated voltage and current of the permanent magnet synchronous motor, and the conversion relationship between the actual voltage and current, a conversion relationship between the estimated value of the permanent magnet synchronous motor current and the estimated value of the voltage in the two-phase rotating coordinate system is obtained with the derivative of the estimated current as the left term; 7) Substituting the average inductance formula on the AC and DC axes and the semi-difference inductance formula on the AC and DC axes into the conversion relationship between the estimated value of the permanent magnet synchronous motor current and the estimated value of the voltage in the two-phase rotating coordinate system with the derivative of the estimated current as the left term, another form of conversion relationship is obtained; 8) Inject a high-frequency voltage signal into the estimated direct axis coordinate system and solve the corresponding current relationship; 9) extracting the high-frequency current equation to which the estimated direct axis responds from the current relationship, the high-frequency current equation containing the information of Δθ; 10) The quadrature-axis current obtained by Park transformation in the system is passed through a bandpass filter to extract the high-frequency current signal, the high-frequency current signal is multiplied by the modulation signal of the same frequency, and then f(Δθ) is obtained through a low-pass filter. The amplitude of f(Δθ) is half of the high-frequency current signal; 11) When the rotor position error is small enough, sin(Δθ) is replaced by Δθ. When f(Δθ) = 0, sin(Δθ) = 0, that is, Δθ = 0, and the actual angle of the rotor is consistent with the estimated angle; 12) The amplitude f(Δθ) is passed into the PI controller, which outputs the estimated speed and then performs integration processing to obtain the estimated angle. The estimated angle acts on the coordinate transformation to form a closed-loop system and realize vector control of the permanent magnet synchronous motor.

2. The permanent magnet synchronous motor control method based on the pulse high frequency voltage injection method according to claim 1 is characterized in that: The voltage equation of the permanent magnet synchronous motor in the three-phase coordinate system established in step 1) is: Among them U a , U b , U c are the terminal voltages of the windings respectively; i a 、i b 、i c are the phase currents of the three-phase windings; E a 、E b 、E c is the back electromotive force of the three-phase winding; R s is the winding phase resistance, and L is the equivalent inductance.

3. The permanent magnet synchronous motor control method based on the pulse high frequency voltage injection method according to claim 2 is characterized in that: Step 2) Simplify the voltage equation in the three-phase coordinate system to the voltage equation in the αβ two-phase stationary coordinate system: Among them, E α 、E β is the back electromotive force; αf is the permanent magnet flux; ω r is the rotor angular velocity; θ is the rotor speed.

4. The permanent magnet synchronous motor control method based on the pulse high frequency voltage injection method according to claim 3 is characterized in that: Step 3) The voltage equation in the two-phase stationary coordinate system is simplified to the voltage equation in the dq two-phase rotating coordinate system through Park transformation. The equation is: u d is the direct axis voltage, u q is the quadrature axis voltage, R is the resistance value, i d is the direct axis current, i q is the quadrature axis current, L d is the direct-axis inductance, L q is the quadrature-axis inductance, ω e is the angular velocity, ψ f is the permanent magnet flux.

5. The permanent magnet synchronous motor control method based on the pulse high frequency voltage injection method according to claim 4 is characterized in that: Step 4) Simplify the voltage equation in the dq two-phase rotating coordinate system to:

6. A permanent magnet synchronous motor control method according to claim 5, characterized in that: The conversion relationship between the estimated voltage and current and the actual voltage and current shown in step 5) is: is the estimated value of the direct axis voltage, is the estimated value of the quadrature axis voltage, is the estimated value of the direct axis current, is the estimated value of the quadrature axis current.

7. The permanent magnet synchronous motor control method based on the pulse high frequency voltage injection method according to claim 6 is characterized in that: Step 6) The conversion relationship between the estimated value of the permanent magnet synchronous motor current and the estimated value of the voltage in the two-phase rotating coordinate system with the derivative of the estimated current as the left term is:

8. The permanent magnet synchronous motor control method based on the pulse high frequency voltage injection method according to claim 7 is characterized in that: Step 7) Substitute the average inductance formula on the AC and DC axes and the semi-differential inductance formula on the AC and DC axes into the conversion relationship between the estimated value of the permanent magnet synchronous motor current and the estimated value of the voltage in the two-phase rotating coordinate system with the derivative of the estimated current as the left term: L is the average inductance on the AC and DC axes, and ΔL is the semi-differential inductance on the AC and DC axes.

9. The permanent magnet synchronous motor control method based on the pulse high frequency voltage injection method according to claim 8 is characterized in that: Step 8) The high-frequency voltage signal injected on the estimated direct axis coordinate system and the corresponding current relationship are solved as follows: in is the high-frequency voltage signal injected into the estimated direct axis coordinate system, U mh is the estimated voltage amplitude of the direct axis, ω h Estimate the angular velocity of the voltage for the direct axis, is the direct axis current value obtained when the voltage signal is injected into the estimated direct axis coordinate system. It is the quadrature-axis current value solved when the voltage signal is injected into the estimated direct-axis coordinate system.

10. The permanent magnet synchronous motor control method based on the pulse high frequency voltage injection method according to claim 9, characterized in that: In step 9), the high-frequency current equation to which the direct axis responds is estimated to be: In step 10), the high-frequency current signal is multiplied by the modulation signal of the same frequency, and then the f(Δθ) obtained by the low-pass filter is: The equivalent substitution formula mentioned in step 11) is approximately:

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