Agricultural permanent magnet motor compound control method and system based on phase advance observer and multi-mode switching

Abstract

The invention discloses an agricultural permanent magnet motor compound control method and system based on a phase advance observer and multi-mode switching, and the method comprises the steps: constructing a parameter adaptive quasi-resonance controller according to a mechanical motion equation and an adaptive law of a motor, taking the output of the parameter adaptive quasi-resonance controller as the q-axis reference current of the motor, and obtaining a low-speed controller; based on a mechanical motion equation of the motor and an online parameter identification method, designing an online parameter identification maximum torque current ratio controller, namely a medium-high speed controller; an undisturbed switching method is designed by a low-speed controller and a medium-high-speed controller; and the output of the phase-lead super-spiral observer is obtained based on the first-layer phase-lead super-spiral observer and the second-layer phase-lead super-spiral observer, the output is compensated to the synthesis controller to obtain a composite controller, and the composite controller acts on the permanent magnet motor by generating a reference current instruction so as to control the rotating speed of the agricultural permanent magnet motor. According to the invention, the inhibition capability of the agricultural motor on periodic and non-periodic disturbance during full-speed domain operation is obviously enhanced.

Description

Technical Field

[0001] The present invention belongs to the field of motor control in agricultural machinery and equipment, and relates to a composite control method and system for an agricultural permanent magnet motor based on a phase advance observer and multi-mode switching. Background Art

[0002] In modern agricultural production, permanent magnet synchronous motors (PMSMs), as core power drive units, are widely used in agricultural equipment such as electric tractors, precision seed drills, and electric transplanters. These motors face unique control challenges during field operations. First, periodic disturbances caused by factors such as inverter dead-zone effects and electrical parameter asymmetry can lead to significant speed fluctuations, seriously affecting system robustness. Second, sudden changes in soil resistance and crop root entanglement encountered during agricultural machinery operation can produce severe non-periodic load shocks. Traditional controllers struggle to effectively suppress the speed fluctuations caused by these disturbances, which not only reduces the operating accuracy and efficiency of agricultural equipment but also directly impacts crop yield and quality.

[0003] Currently, active disturbance rejection control (ADRC) performs well in handling non-periodic disturbances (such as load and inertia changes). However, its inherent fixed bandwidth parameters make it difficult to adapt to the differentiated control performance requirements of different agronomic conditions such as plowing, sowing, and harvesting. In particular, it lacks effective suppression strategies for periodic disturbances. Summary of the Invention

[0004] To address the multi-source disturbance suppression challenges faced by existing agricultural permanent magnet synchronous motor drive systems operating at full speed, this paper proposes a composite control method and system for agricultural permanent magnet synchronous motors based on a phase-advanced superhelical observer and multi-mode switching. This control strategy significantly enhances the ability of agricultural motors to suppress both non-periodic and periodic disturbances at full speed, providing strong support for efficient and precise smart agriculture operations. This helps improve agricultural production efficiency, reduce production costs, and ensure the suitability and consistency of the crop growth environment, thereby promoting the sustainable development of agricultural production.

[0005] The present invention achieves the above technical objectives through the following technical means.

[0006] Composite control method for agricultural permanent magnet motor based on phase advance observer and multi-mode switching:

[0007] According to the mechanical motion equation and adaptive law of the motor, the parameter adaptive quasi-resonant controller is constructed, and the motor stator current i d =0 control strategy, the output of the parameter adaptive quasi-resonant controller is used as the q-axis reference current to obtain a low-speed controller;

[0008] Based on the mechanical motion equations of the motor and the online parameter identification method, an online parameter identification maximum torque-to-current ratio controller, i.e., a medium- and high-speed controller, is designed.

[0009] The disturbance-free switching method is designed by the low-speed controller and the medium-high-speed controller: when the motor speed satisfies n≤n low When K low =1,K high =0, use low speed controller; when the motor speed meets n high When ≤n, K low =0,K high =1, use medium and high speed controller; when the motor speed meets n low <n<n high , using a synthetic controller; where n low Indicates the low speed setting value, n high Indicates the medium and high speed setting value, K low is the dynamic weight coefficient in the low-speed zone, K high is the dynamic weight coefficient in the medium and high speed zone;

[0010] Based on the first-layer phase-lead super-helical observer and the second-layer phase-lead super-helical observer, the output of the phase-lead super-helical observer is obtained and compensated to the synthetic controller to obtain a composite controller. The composite controller acts on the speed loop control loop of the motor by generating a reference current command, and acts on the permanent magnet motor through a closed-loop path of current loop control, power conversion, and torque response to achieve speed control of the agricultural permanent magnet motor.

[0011] Furthermore, the adaptive law is designed based on the mechanical motion equation of the motor, specifically:

[0012]

[0013]

[0014] Among them, k qi is the adaptive gain, α, β, δ are the adaptive gains, e is the motor angular velocity error, ξ i , γ i ,η i is the adaptive coefficient, ω ref is the motor reference angular velocity, ω is the rotor mechanical angular velocity, and i=1, 2.

[0015] Furthermore, the online parameter identification method is designed based on the voltage equation of the motor. First, the PWM voltage is introduced into the motor model to obtain the motor voltage equation in the α-β coordinate system and the dq coordinate system. Then, by distinguishing the voltage values ​​under the effective vector and zero vector of PWM, a recursive least squares method is constructed to identify the parameters L in real time online. d 、L q , ψf :

[0016]

[0017]

[0018] Where, R is the stator winding phase resistance, L d 、L q are the stator winding d-axis and q-axis inductances, ω e is the electrical angular velocity, ψ f is the motor flux, i dsa 、i qsa 、u dsa 、u qsa Represent the current and voltage of d and q axes under the action of effective vector, i dsz 、i qsz are the currents of d and q axes under the action of zero vector respectively.

[0019] Furthermore, the synthesis controller is:

[0020]

[0021] in, is the d-axis reference current output by the synthetic controller, is the q-axis reference current output by the synthetic controller, is the q-axis reference current output by the low-speed controller, is the d-axis reference current output by the medium and high speed controller, It is the q-axis reference current output by the medium and high speed controller.

[0022] Furthermore, the dynamic weight coefficient of the medium and high speed zone Low-speed zone dynamic weight coefficient K low =1-K high , n is the motor speed, n low Indicates the low speed setting value, n high Indicates medium to high speed setting value.

[0023] Furthermore, the first-layer phase-advancing super-helical observer is:

[0024]

[0025] Among them, e 11 is the disturbance observation error of the first-layer phase-advancing super-helical observer, z 11 is the angular velocity observation value of the first-layer phase-advancing super-helical observer, b is the motor torque coefficient, z 12 is the initial observation value of the lumped perturbation of the first-layer phase-advancing super-helical observer, is the stator q-axis reference current, λ11 ,λ 12 ,λ 13 is an adjustable parameter, f1 is the differential term of the disturbance observation error of the first-layer phase-advancing super-helical observer, and sign is the sign function.

[0026] Furthermore, the second-layer phase-advancing super-helical observer is:

[0027]

[0028] Among them, e 21 is the perturbation observation error of the second-layer phase-advancing super-helical observer, λ 21 is the angular velocity observation value of the second-layer phase-advancing super-helical observer, z 22 is the lumped perturbation residual observation value of the second-layer phase-advancing super-helical observer, λ 21 ,λ 22 and λ 23 is an adjustable parameter, and f2 is the differential term of the disturbance observation error of the second-layer phase-advancing super-helical observer.

[0029] Furthermore, the limited instruction filtering method is used to process the differential term and

[0030] Furthermore, the output z of the phase-advancing super-helical observer is 12 +z 22 ≈d t , d t is the lumped disturbance in the motor's mechanical motion equation, and the compensation term 1 / b=J / 1.5P n ψ f Convert the lumped disturbance into an equivalent q-axis current increment, b is the motor torque coefficient, J is the moment of inertia, P n is the number of motor pole pairs, ψ f is the motor flux.

[0031] A composite control system for an agricultural permanent magnet motor based on a phase advance observer and multi-mode switching, comprising:

[0032] The host computer realizes the writing and debugging of the control method of the present invention and communicates with the control unit in real time;

[0033] A control unit stores and executes the control method of the present invention, collects the three-phase current of the stator of the permanent magnet synchronous motor and the DC voltage of the DC power supply, and processes the pulse information of the motor encoder to obtain the position and speed of the rotor;

[0034] DC power supply, which provides adjustable DC bus voltage for the inverter and is equipped with overcurrent protection;

[0035] The inverter generates a corresponding space voltage vector according to the control instructions of the control unit, thereby driving the permanent magnet synchronous motor;

[0036] A permanent magnet synchronous motor with an incremental encoder installed to provide feedback on the rotor position and speed.

[0037] The load unit is used to apply load torque to the permanent magnet synchronous motor.

[0038] The beneficial effects achieved by the present invention are:

[0039] (1) The present invention uses a parameter-adaptive quasi-resonant controller to suppress the low-speed pulsation of the motor, reduces the motor torque ripple, and thus significantly improves the robustness of the permanent magnet synchronous motor, reduces the impact of the resonance term on the dynamic performance of the motor, and ensures the speed regulation accuracy. The combination of the observer and the quasi-resonant controller improves the performance of suppressing multi-source disturbances of the motor speed and further reduces energy loss.

[0040] (2) The present invention uses an online parameter identification maximum torque current ratio controller to improve the speed performance of the permanent magnet synchronous motor under medium and high speed conditions. It uses online parameter identification to dynamically correct the inductance flux parameters, effectively avoiding parameter drift caused by factors such as temperature rise and magnetic saturation, and significantly improving the torque control accuracy of agricultural implement operations under medium and high speed conditions.

[0041] (3) The present invention uses a phase-advanced super-helical extended state observer to quickly and accurately observe non-periodic disturbances, reduce the impact of sudden loads and model errors on the motor speed, and achieve faster and more accurate estimation of the motor speed and lumped disturbances, thereby improving the robustness of the permanent magnet synchronous motor and ensuring its excellent dynamic performance.

[0042] (4) The present invention uses a constrained instruction filter to process the disturbance observation error, thereby reducing the undesirable characteristics of the error signal, thereby improving the utilization rate of the disturbance observation error, improving the phase tracking performance of the disturbance, and enabling the observer to estimate more quickly. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic diagram of the composition of the composite control system of the present invention;

[0044] Figure 2 This is a schematic structural diagram of a control unit of the present invention;

[0045] Figure 3 Schematic diagram of the structure of the phase-advanced super-helical extended state observer of the present invention;

[0046] Figure 4 Schematic diagram of the structure of the restricted instruction filter of the present invention;

[0047] Figure 5 Schematic diagram of the structure of the adaptive gain quasi-resonant controller of the present invention;

[0048] Figure 6 A flow chart for implementing the method of the present invention;

[0049] Figure 7 A diagram of the motor speed suppressed by the non-periodic disturbance of the phase advance observer of the present invention;

[0050] FIG8( a ) is a diagram of the motor speed without quasi-resonant control according to the present invention;

[0051] FIG8( b ) is a speed response curve diagram of the parameter adaptive quasi-resonant control of the present invention;

[0052] FIG8( c ) is a diagram showing the speed harmonic analysis without quasi-resonant control according to the present invention;

[0053] FIG8( d ) is a diagram showing the speed harmonic analysis of the parameter adaptive quasi-resonant control of the present invention. DETAILED DESCRIPTION

[0054] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily implement the present invention based on the content disclosed in this specification. To make the objectives, technical solutions, and effects of the present invention more clear and explicit, the technical solutions in the examples of the present invention are clearly and completely described below with reference to the accompanying drawings. It should be noted that the described embodiments are only some embodiments of the present invention, not all embodiments. They are intended only to explain the present invention and are not intended to limit the present invention.

[0055] The present invention provides a composite control method and system for an agricultural permanent magnet motor based on a phase advance observer and multi-mode switching, which is applicable to various agricultural equipment.

[0056] An embodiment of a composite control system for agricultural permanent magnet motors based on a phase advance observer and multi-mode switching, which comprises the following components: Figure 1 As shown, it includes the following parts:

[0057] The host computer is used to write and debug the control program of the present invention and to communicate with the control unit in real time via Ethernet to observe and record the working status of the permanent magnet synchronous motor;

[0058] A control unit uses a Flash memory to store the control program of the present invention, uses a TMS320C28346 DSP processor to execute the control program of the present invention at an interrupt frequency of 10 kHz, uses an ADC board to collect the three-phase current of the stator of the permanent magnet synchronous motor and the DC voltage of the DC power supply, uses an encoder board to process the encoder pulse information to obtain the position and speed of the rotor, and communicates with the host computer in real time via Ethernet;

[0059] The DC power supply provides the inverter with an adjustable DC bus voltage of 200V and is also equipped with a 10A overcurrent protection.

[0060] The inverter uses insulated gate bipolar transistors with a switching frequency of up to 10kHz as switching tubes to generate the corresponding space voltage vector according to the control instructions of the control unit, thereby driving the permanent magnet synchronous motor;

[0061] The permanent magnet synchronous motor, as the controlled object of the entire system, is equipped with an incremental encoder to feedback the rotor position and rotor speed;

[0062] The load unit is used to apply load torque to the permanent magnet synchronous motor.

[0063] like Figure 2 As shown, the control unit includes:

[0064] Phase-advanced super-helical extended state observer, used to observe the rotor speed of the permanent magnet synchronous motor and the lumped disturbances to which the permanent magnet synchronous motor is subjected;

[0065] A parameter-adaptive quasi-resonant controller is used to suppress the periodic disturbance of the permanent magnet synchronous motor speed and, together with the phase-advanced super-helical extended state observer, to control the permanent magnet synchronous motor rotor speed.

[0066] The d-axis current PI module is used to calculate the d-axis given voltage u based on the d-axis current error d ;

[0067] The q-axis current PI module is used to calculate the q-axis given voltage u based on the q-axis current error q ;

[0068] Clark transformation module is used to transform the three-phase current collected by the sensor into the α-axis current i in the static α-β coordinate system. α and β-axis current i β ;

[0069] The Park transformation module is used to transform the α-axis current i in the stationary α-β coordinate system α and β-axis current i β Transformed into the d-axis current i in the rotating dq coordinate systemd and q-axis current i q ;

[0070] The Park inverse transform module is used to convert the d-axis given voltage u in the rotating dq coordinate system d and q-axis given voltage u q Transformed into the α-axis given voltage u in the stationary α-β coordinate system α and β-axis given voltage u β ;

[0071] Space vector pulse width modulation module, used to give voltage u according to the α axis α , β-axis given voltage u β The acquired DC bus voltage is used to perform pulse width modulation on the inverter, thereby realizing speed control of the permanent magnet synchronous motor.

[0072] Corresponding to the embodiment of the above system, an embodiment of a composite control method for agricultural permanent magnet motor based on phase advance observer and multi-mode switching is as follows: Figure 6 As shown, the following steps are included:

[0073] S1, use the coordinate transformation method to establish a rotating coordinate system model for the permanent magnet synchronous motor. Assuming that the permanent magnet synchronous motor system is in an ideal state, the voltage equation of the permanent magnet synchronous motor in the rotating coordinate system is:

[0074]

[0075] The torque equation of the permanent magnet synchronous motor is:

[0076] T e =1.5P n (ψ d i q -ψ q i d )=1.5P n i q [ψ f +(L d -L q )i d ]

[0077] Considering the periodic and non-periodic disturbances of the motor system, the mechanical motion equation of the permanent magnet synchronous motor is:

[0078]

[0079] Among them, u d 、u q are the stator d and q axis voltages respectively; i d 、i q are the stator d-axis and q-axis currents respectively; ψd , ψ q are the stator d-axis and q-axis flux linkages respectively; R is the stator winding phase resistance; ω e is the electrical angular velocity; ψ f is the motor flux; K is the motor torque coefficient; is the stator q-axis reference current; L d 、L q are the d-axis and q-axis inductances of the stator winding respectively; T e is the electromagnetic torque; P n is the number of motor pole pairs; T L is the load torque; T h is the periodic disturbance; B is the friction coefficient; J is the moment of inertia; the motor torque coefficient ω is the rotor mechanical angular velocity, and ω e =P n ω;d t is the lumped disturbance, and

[0080]

[0081] S2, the adaptive law designed based on the mechanical motion equation of the motor is:

[0082]

[0083]

[0084] Among them, k qi is the adaptive gain, α, β, δ are the adaptive gains, ξ i , γ i ,η i is the adaptive coefficient, i=1, 2; e is the motor angular velocity error, ω ref is the motor reference angular velocity.

[0085] S3, based on the mechanical motion equation of the motor and the adaptive law, the parameter adaptive quasi-resonant controller is constructed as follows:

[0086]

[0087] in, u qri is the output of the quasi-resonant controller, ω di =2%·k qi is the cutoff frequency, ω ri =i·P n ω is the resonant frequency, k qi Inductance is the resonant controller gain, i=1, 2.

[0088] Further, using i d=0 control strategy, the output of the parameter adaptive quasi-resonant controller is used as the q-axis reference current, and the low-speed controller is obtained as:

[0089]

[0090] Among them, u q1 、u q2 They represent the outputs of the parameter adaptive quasi-resonant controller respectively.

[0091] Adopting parameter adaptive quasi-resonant controller ( Figure 5 ), selective harmonic compensation is achieved by dynamically adjusting the resonant gain and frequency parameters, effectively suppressing the periodic disturbance of agricultural motors under low-speed and high-torque conditions, and significantly improving the system's anti-interference ability and operational stability.

[0092] S4, based on the voltage equation design of the motor, online parameter identification method, real-time update L d 、L q , ψ f , to compensate for the effects of temperature, magnetic circuit saturation, etc. Introducing the PWM voltage into the motor model, the motor voltage equation in the α-β coordinate system and the dq coordinate system is obtained:

[0093]

[0094]

[0095] Among them, u ds 、u qs is the d and q axis voltage of the switch model in the dq coordinate system, u αs 、u βs is the α and β axis voltage of the switch model in the α-β coordinate system, V dc is the DC bus voltage, θ e is the motor electrical angle; S a 、S b 、S c is the switch state in the three-phase inverter, 1 represents on, 0 represents off, the effective vector of PWM is (100, 010, 001, 110, 101, 011), and the zero vector of PWM is (000, 111).

[0096] By distinguishing the voltage values ​​under the action of the effective vector and zero vector of PWM, a recursive least squares method is constructed to identify the parameters in real time online:

[0097]

[0098]

[0099] Among them, i dsa 、i qsa、u dsa 、u qsa Represent the current and voltage of d and q axes under the action of effective vector, i dsz 、i qsz are the currents of d and q axes under the action of zero vector respectively.

[0100] Through the above formula, the expressions of dq axis inductance, resistance and magnetic flux can be written, namely:

[0101]

[0102]

[0103] Real-time update d 、L q , ψ f , to compensate for the effects of temperature, magnetic circuit saturation, etc.

[0104] S5, based on the mechanical motion equation of the motor and the online parameter identification method, the online parameter identification maximum torque current ratio controller is designed, that is, the medium and high speed controller is:

[0105]

[0106] S6, design of a disturbance-free switching method based on a low-speed controller and a medium- and high-speed controller

[0107] Define the upper and lower thresholds for speed switching:

[0108] n low =0.15n rated , n high =0.25n rated

[0109] Among them, n rated Indicates rated speed, n low Indicates the low speed setting value, n high Indicates medium and high speed setting value;

[0110] In actual engineering, the rotational speed is often expressed in rpm (revolutions per minute), which needs to be converted through the angular velocity ω (rad / s): n = 60ω / 2π.

[0111] Construct a linear transition weight coefficient based on the speed switching range:

[0112]

[0113] Among them, K low is the dynamic weight coefficient in the low-speed zone, K high is the dynamic weight coefficient in the medium and high speed zone.

[0114] In order to meet the control requirements of different speeds, a weighted hybrid control method is designed, that is, the synthetic controller is:

[0115]

[0116] When the speed satisfies n≤ nlow When K low =1,K high =0, use low speed controller; when the speed meets n high When ≤n, K low =0,K high =1, use medium and high speed controller; when the speed meets n low <n<n high , weighted hybrid control is adopted to ensure smooth transition of current instructions.

[0117] S7, considering the observer perturbation observation error e 11 and e 21 Fluctuation, a limited instruction filtering method is used to deal with the differential term and Design a constrained command filter to perturb the observation error (see Figure 4 )as follows:

[0118]

[0119] Among them, e 1d and e 2d is the disturbance observation error after filtering, ω g is the filter cutoff frequency, and parameter θ adjusts the bandwidth;

[0120] Get the differential term of the disturbance observation error after filtering Here, amplitude limitation, rate limitation and bandwidth limitation are used to limit the amplitude of input signal, limit the sudden change of input signal and limit the bandwidth of output signal respectively, which avoids direct numerical differentiation and ensures The value of is bounded.

[0121] S8, in order to observe the non-periodic disturbance of the motor system, the first-layer phase-advanced super-helical observer is designed as:

[0122]

[0123] The second-layer phase-advancing super-spiral observer is designed as:

[0124]

[0125] Among them, z 11 and z 21 are the angular velocity observation values ​​of the first and second layer observers, z 12 and z22 They are the lumped disturbance preliminary observation value and residual observation value of the first and second level observers, e 11 、e 21 is the observed error, the operator Represents a signed fractional power operation, real number x = e 11 , e 21 , fractional exponent y = 3 / 4, 1 / 2, sign(x) is the sign function, λ 11 ,λ 12 ,λ 13 ,enter 21 ,enter 22 and λ 23 is an adjustable parameter, define λ 11 =λ 21 =ω o ,λ 12 =λ 22 =ω o 2 ,λ 13 =λ 23 =ω o ,ω o is the bandwidth of the extended state observer, is the differential term of the disturbance observation error.

[0126] Furthermore, based on the first-layer phase-advancing super-helical observer and the second-layer phase-advancing super-helical observer, the output value of the phase-advancing observer is (z 12 +z 22 ) / b. Figure 3 Shown is the phase advance observer.

[0127] S9, the disturbance observation value of the phase-advancing super-helical observer is compensated to the synthetic controller, and the observer output z 12 +z 22 ≈d t The lumped disturbance in the motor's mechanical motion equation is actually estimated, and the compensation term 1 / b=J / 1.5P n ψ f The lumped disturbance is converted into an equivalent q-axis current increment to offset the effect of the disturbance on the speed, and the composite controller is obtained:

[0128]

[0129] The composite controller generates a reference current command, acts on the motor's speed loop control circuit, and acts on the permanent magnet synchronous motor through a closed-loop path of current loop control, power conversion, and torque response to achieve speed control of the agricultural motor.

[0130] An embodiment of a composite control method and system for an agricultural permanent magnet motor based on a phase advance observer and multi-mode switching has been specifically explained and illustrated, thereby making the technical solution of the present invention more clear and convenient for engineers to implement. Based on this example, the effects of the present invention are further demonstrated through experiments.

[0131] In order to verify the excellent robustness of the present invention, the load torque of the permanent magnet synchronous motor is suddenly changed by using a load unit when the rotor speed of the permanent magnet synchronous motor is 100 rpm to test the robustness of the embodiment. Figure 7 As shown, it is not difficult to see that the speed drop of this embodiment in the experiment is small and the speed recovery time is short, which can prove that the present invention has excellent robustness. The steady-state speed performance of the motor is shown in Figures 8(a), (b), (c), and (d). Figure 8(a) is the speed of non-resonant control, and Figure 8(b) is the speed of parameter adaptive quasi-resonant control. It is obvious that the quasi-resonant controller can effectively reduce speed fluctuations; Figure 8(c) is the speed harmonic analysis of non-resonant control, and Figure 8(d) is the speed harmonic analysis of parameter adaptive quasi-resonant control. It is obvious that the quasi-resonant controller can effectively reduce the 1st and 2nd speed harmonics. In summary, the present invention achieves a significant improvement in the robustness of the permanent magnet synchronous motor while ensuring the excellent dynamic performance and speed regulation accuracy of the permanent magnet synchronous motor.

[0132] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative uses of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0133] Although the present invention has been described in terms of various specific embodiments, those skilled in the art will appreciate that the present invention may be implemented with modifications within the spirit of the claims. Therefore, any obvious improvements, substitutions, or modifications that a person skilled in the art can make without departing from the spirit of the present invention are within the scope of protection of the present invention.

Claims

1. A composite control method for agricultural permanent magnet motors based on a phase advance observer and multi-mode switching, characterized by: According to the mechanical motion equation and adaptive law of the motor, the parameter adaptive quasi-resonant controller is constructed, and the motor stator current i d =0 control strategy, the output of the parameter adaptive quasi-resonant controller is used as the q-axis reference current to obtain a low-speed controller; Based on the mechanical motion equations of the motor and the online parameter identification method, an online parameter identification maximum torque-to-current ratio controller, i.e., a medium- and high-speed controller, is designed. The disturbance-free switching method is designed by the low-speed controller and the medium-high-speed controller: when the motor speed satisfies n≤n low When -K low =1,K high =0, use low speed controller; when the motor speed meets n high When ≤n, K low =0,K high =1, use medium and high speed controller; when the motor speed meets n low <n<n high , using a synthetic controller; Among them, n low Indicates low speed setting value, n high Indicates the medium and high speed setting value, K low is the dynamic weight coefficient in the low-speed zone, K high is the dynamic weight coefficient in the medium and high speed zone; Based on the first-layer phase-lead super-helical observer and the second-layer phase-lead super-helical observer, the output of the phase-lead super-helical observer is obtained and compensated to the synthetic controller to obtain a composite controller. The composite controller acts on the speed loop control loop of the motor by generating a reference current command, and acts on the permanent magnet motor through a closed-loop path of current loop control, power conversion, and torque response to achieve speed control of the agricultural permanent magnet motor.

2. The agricultural permanent magnet motor composite control method based on phase advance observer and multi-mode switching according to claim 1 is characterized in that: The adaptive law is designed based on the mechanical motion equation of the motor, specifically: Among them, k qi is the adaptive gain, α, β, δ are the adaptive gains, e is the motor angular velocity error, ξ i , γ i ,η i is the adaptive coefficient, ω ref is the motor reference angular velocity, ω is the rotor mechanical angular velocity, and i=1, 2.

3. The agricultural permanent magnet motor composite control method based on phase advance observer and multi-mode switching according to claim 1 is characterized in that: The online parameter identification method is designed based on the voltage equation of the motor. First, the PWM voltage is introduced into the motor model to obtain the motor voltage equation in the α-β coordinate system and the dq coordinate system. Then, by distinguishing the voltage values ​​under the effective vector and zero vector of PWM, a recursive least squares method is constructed to identify the parameters L in real time online. d 、L q , ψ f : Where, R is the stator winding phase resistance, L d 、L q are the stator winding d-axis and q-axis inductances, ω e is the electrical angular velocity, ψ f is the motor flux, i dsa 、i qsa 、u dsa 、u qsa Represent the current and voltage of d and q axes under the action of effective vector, i dsz 、i qsz are the currents of d and q axes under the action of zero vector respectively.

4. The agricultural permanent magnet motor composite control method based on phase advance observer and multi-mode switching according to claim 1 is characterized in that: The synthesis controller is: in, is the d-axis reference current output by the synthetic controller, is the q-axis reference current output by the synthetic controller, is the q-axis reference current output by the low-speed controller, is the d-axis reference current output by the medium and high speed controller, It is the q-axis reference current output by the medium and high speed controller.

5. The agricultural permanent magnet motor composite control method based on phase advance observer and multi-mode switching according to claim 4 is characterized in that: Dynamic weight coefficient in medium and high speed zone Low-speed zone dynamic weight coefficient K low =1-K high , n is the motor speed, n low Indicates low speed setting value, n high Indicates medium to high speed setting value.

6. The agricultural permanent magnet motor composite control method based on phase advance observer and multi-mode switching according to claim 1 is characterized in that: The first-layer phase-advancing super-spiral observer is: Among them, e 11 is the disturbance observation error of the first-layer phase-advancing super-helical observer, z 11 is the angular velocity observation value of the first-layer phase-advancing super-helical observer, b is the motor torque coefficient, z 12 is the preliminary observation of the lumped perturbation of the first-layer phase-advancing super-helical observer, is the stator q-axis reference current, λ 11 ,λ 12 ,λ 13 is an adjustable parameter, is the differential term of the disturbance observation error of the first-layer phase-advancing super-helical observer, and sign is the sign function.

7. The agricultural permanent magnet motor composite control method based on phase advance observer and multi-mode switching according to claim 6 is characterized in that: The second-layer phase-advancing super-spiral observer is: Among them, e 21 is the perturbation observation error of the second-layer phase-advancing super-helical observer, z 21 is the angular velocity observation value of the second-layer phase-advancing super-helical observer, z 22 is the lumped perturbation residual observation value of the second-layer phase-advancing super-helical observer, λ 21 ,λ 22 and λ 23 is an adjustable parameter, is the differential term of the disturbance observation error of the second-layer phase-advancing super-helical observer.

8. The agricultural permanent magnet motor composite control method based on phase advance observer and multi-mode switching according to claim 7 is characterized in that: Using limited instruction filtering to process differential terms and 9. The agricultural permanent magnet motor composite control method based on phase advance observer and multi-mode switching according to claim 8, characterized in that: The output z of the phase-advancing super-helical observer 12 +z 22 ≈d t , d t is the lumped disturbance in the motor's mechanical motion equation, and the compensation term 1 / b=J / 1.5P n ψ f Convert the lumped disturbance into an equivalent q-axis current increment, b is the motor torque coefficient, J is the moment of inertia, P n is the number of motor pole pairs, ψ f is the motor flux.

10. A system for implementing the agricultural permanent magnet motor composite control method based on a phase advance observer and multi-mode switching according to any one of claims 1 to 9, comprising: The host computer realizes the writing and debugging of the control method of the present invention and communicates with the control unit in real time; A control unit stores and executes the control method of the present invention, collects the three-phase current of the stator of the permanent magnet synchronous motor and the DC voltage of the DC power supply, and processes the pulse information of the motor encoder to obtain the position and speed of the rotor; DC power supply, which provides adjustable DC bus voltage for the inverter and is equipped with overcurrent protection; The inverter generates a corresponding space voltage vector according to the control instructions of the control unit, thereby driving the permanent magnet synchronous motor; A permanent magnet synchronous motor with an incremental encoder installed to provide feedback on the rotor position and speed. The load unit is used to apply load torque to the permanent magnet synchronous motor.

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