Hybrid control switching method of double-stator modulation motor in complex environment

Abstract

The invention discloses a hybrid control switching method for a double-stator modulation motor in a complex environment. The method comprises the following steps: acquiring a mathematical model of the double-stator modulation motor in a natural coordinate system; performing coordinate transformation to obtain a mathematical model under a rotating coordinate system; according to the relation between the coordinate transformation angles of the excitation winding and the control winding, two current directional vector control algorithms of direct current excitation and alternating current excitation capable of independently controlling operation are determined; the double-stator modulation motor is controlled by direct-current excitation at a low speed, the double-stator modulation motor is controlled by alternating-current excitation at a middle speed and a high speed, and control switching between the direct-current excitation and the alternating-current excitation is carried out according to the obtained specific relation; according to the method, a decoupling control strategy is formulated according to the space vector relation between the excitation winding and the control winding disclosed in the model, an excitation current vector directional control algorithm is provided, switching between the two excitation control methods is achieved through the relation between the coordinate transformation angles of the excitation winding and the control winding, and the vehicle performance is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of transformer substation safety, and in particular to a hybrid control switching method for a dual-stator modulation motor in a complex environment. Background Art

[0002] In recent years, electric vehicles have attracted much attention as an emerging industry. As they are conducive to solving problems such as limited oil resources and aggravated air pollution, they have also become a very important strategic research industry in my country. Electric vehicles are generally driven by hub motors. The characteristics of hub motor drive are that the drive motor is directly connected to the wheel or directly installed on the wheel, omitting mechanical parts and improving transmission efficiency.

[0003] Among them, the stator part of the dual-stator flux-modulated motor (DSFMM) adopts an inner and outer double stator structure design method, and the rotor part adopts a cage-type connection design method of the adjustable magnet block, thereby achieving dual simplification of the stator and rotor structures. Its wide torque and speed adjustment range and high power density make it widely applicable to the field of electric vehicles. However, in the existing use process, most of them are driven by a single control method. At the same time, due to the different performance requirements of electric vehicles for motors under low-speed and high-speed conditions, a single control method affects the performance of the vehicle. Summary of the invention

[0004] The main technical problem solved by the present invention is to provide a hybrid control switching method for a dual-stator modulation motor in a complex environment. By controlling the control requirements of the motor under different excitations, current-oriented vector control is used to achieve the fusion of motor control under different excitations and realize control switching during the control process.

[0005] In order to solve the above technical problems, a technical solution adopted by the present invention is to provide a hybrid control switching method of a dual-stator modulation motor under complex environment, the steps of which are:

[0006] Step 1: Obtain a mathematical model of the dual-stator modulation motor in a natural coordinate system;

[0007] Step 2: Perform coordinate transformation on the mathematical model obtained in step 1 to obtain a mathematical model in a rotating coordinate system;

[0008] Step 3: According to the specific relationship between the coordinate transformation angles of the excitation winding and the control winding in the rotating coordinate system, two current oriented vector control algorithms, DC excitation and AC excitation, which can be independently controlled and operated, are determined;

[0009] Step 4: Use a DC excitation current oriented vector control algorithm to control the dual-stator modulation motor at low speed, and use an AC excitation current oriented vector control algorithm to control the dual-stator modulation motor at medium and high speed. According to the specific relationship obtained, control switching between DC excitation and AC excitation is performed to achieve hybrid control of the dual-stator modulation motor under different excitations.

[0010] Furthermore, in step 1, the mathematical model in the three-phase fixed coordinate system is as follows:

[0011] The voltage vector equation is:

[0012]

[0013] The flux vector equation is:

[0014]

[0015] The torque equation is:

[0016]

[0017] In the formula, R p and R s Represent the resistance of the excitation winding and the control winding respectively, and Respectively represent the current of the excitation winding and the control winding in the fixed coordinate system, ω p and ω s Represent the electrical angular frequency of the excitation winding and the control winding, L p and L s They represent the self-inductance of the field winding and the control winding, respectively, and p r is the number of rotor pole pairs, and They represent the current vectors of the excitation winding and the control winding in the fixed coordinate system, and They represent the frequency conversion of the excitation winding to the control winding and the control winding to the excitation winding, respectively. ps is the mutual inductance of the windings.

[0018] Furthermore, in the step 2, according to the vector coordinate transformation rules, the dual dq coordinate system is used for decoupling, and the two sets of stator windings in the dual-stator modulation motor are transformed into two rotating coordinate systems with different angular velocities respectively.

[0019] Furthermore, the coordinate transformation rules of each vector are:

[0020] Assuming the field winding coordinate transformation angle is θ, the coordinate transformation rules of each vector of the field winding are:

[0021]

[0022] In the formula, represents the flux vector of the field winding in the rotating coordinate system, represents the current of the field winding in the rotating coordinate system;

[0023] Assuming the coordinate transformation angle of the control winding is θr-θ, the coordinate transformation rules of each vector of the control winding are:

[0024]

[0025]

[0026] In the formula, represents the flux vector of the field winding in the rotating coordinate system, Represents the current of the excitation winding in the rotating coordinate system.

[0027] Furthermore, in step 2, the mathematical model in the rotating coordinate system is as follows:

[0028] The flux equation of the excitation winding is:

[0029]

[0030] The control winding flux equation is:

[0031]

[0032] The voltage vector equation is:

[0033]

[0034] The torque equation is:

[0035]

[0036] In the formula, R p and R s Represent the resistance of the excitation winding and the control winding respectively, and denote the currents of the field winding and control winding in the fixed coordinate system, ω and ω respectively r Represent the electrical angular frequency and the rotor electrical angular frequency respectively, L p and L s They represent the self-inductance of the field winding and the control winding, respectively, and p r The number of rotor pole pairs, and They represent the current vectors of the excitation winding and the control winding in the rotating coordinate system respectively.

[0037] Furthermore, in step 3, the specific relationship is: according to the magnetic flux equation of the excitation winding in the rotating coordinate system, another form of the torque equation is obtained:

[0038]

[0039] In the formula, λ pd The formula represents the magnetic flux vector of d and q axes, i sq and i sd Represents the q-axis current and d-axis current in the rotating coordinate system.

[0040] Furthermore, in step 3, the DC excitation current oriented vector control algorithm is:

[0041] Let the field winding coordinate transformation angle θ = 0, that is, the field winding equation is located in a fixed dq coordinate system, which means that a DC current is passed through the field winding, and the control winding coordinate transformation angle θ r -θ=θ r , that is, the control winding d-axis coincides with the rotor d-axis, and the control winding current frequency is the same as the rotor angular velocity, that is, the control winding vectors are all in the rotor coordinate system;

[0042] The permanent magnetic flux generated by the DC current in the excitation winding is modulated by the rotor and coupled with the magnetomotive force of the control winding. For this reason, the dual-stator modulation motor is controlled as a permanent magnet synchronous motor.

[0043] Furthermore, in step 3, the AC excitation current oriented vector control algorithm is:

[0044] Assume that the excitation winding coordinate transformation angle θ≠0, and the excitation winding dq coordinate system rotation angular velocity ω≠0rad / s, which means that AC current is passed through the excitation winding. Under AC excitation, the d-axis of the excitation winding coordinate system is controlled to coincide with the current vector, so that the variables in the excitation winding and control winding equations are DC quantities at any time.

[0045] Furthermore, in step four, the control switching method is: when the speed reaches the switching value, according to the pre-collected speed and motor parameters, the control algorithm to be switched performs reverse operation to obtain control parameters matching the current speed, and then inputs the control parameters into the control algorithm to be switched, and the control algorithm to be switched takes over the control algorithm in control to control the dual-stator modulation motor.

[0046] The beneficial effects of the present invention are:

[0047] The present invention performs coordinate transformation on voltage, flux and torque equations based on the obtained mathematical model of the dual-stator modulation motor, derives the mathematical model under the rotating coordinate system, and formulates a decoupling control strategy by using the spatial vector relationship between the excitation winding and the control winding revealed in the model. A DC excitation current vector oriented control algorithm and an AC excitation control algorithm current vector oriented control algorithm based on the dual-stator winding coordinate system are proposed. The relationship between the coordinate transformation angles of the excitation winding and the control winding is used to merge the two to achieve switching between the two excitation control methods, so as to use different control methods in different environments and improve vehicle performance.

[0048] In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the following specifically cites preferred embodiments and describes them in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only five of the drawings in this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0050] Figure 1 It is a flowchart of the application method;

[0051] Figure 2 It is the rotating coordinate system and current vector diagram;

[0052] Figure 3 It is the control strategy block diagram;

[0053] Figure 4 It is a block diagram of the experimental results at different frequencies;

[0054] Figure 5 It is the corresponding waveform of speed tracking. DETAILED DESCRIPTION

[0055] In order to facilitate the understanding of the present invention, the present invention is described in more detail below in conjunction with the accompanying drawings and specific embodiments. Preferred embodiments of the present invention are provided in the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described in this specification. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0056] It should be noted that, unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in this specification includes any and all combinations of one or more related listed items.

[0057] See also Figure 1-5 , Figure 1 The present invention shows a hybrid control switching method for a dual-stator modulation motor in a complex environment, wherein the steps are:

[0058] Step S1, obtaining a mathematical model of the dual-stator modulation motor in a natural coordinate system;

[0059] Step S2, performing coordinate transformation on the mathematical model obtained in step S2 to obtain a mathematical model in a rotating coordinate system;

[0060] Step S3, according to the specific relationship between the coordinate transformation angles of the excitation winding and the control winding in the rotating coordinate system, two current oriented vector control algorithms, namely, DC excitation and AC excitation, which can be independently controlled and operated, are determined;

[0061] Step S4, using a DC excitation current oriented vector control algorithm to control the dual-stator modulation motor at low speed, and using an AC excitation current oriented vector control algorithm to control the dual-stator modulation motor at medium and high speeds, and switching between DC excitation and AC excitation according to the specific relationship obtained to achieve hybrid control of the dual-stator modulation motor under different excitations.

[0062] In step S1, the two sets of stator windings in the DSFMM structure have different pole pairs. If the rotor is a complete circular magnetic structure, theoretically there will be no coupling between the two sets of stator windings. In terms of structure, the two sets of windings are respectively called outer stator windings and inner stator windings. In terms of control mode, the two sets of windings can be respectively called excitation windings and control windings.

[0063] The magnetically regulated rotor refers to a cup-shaped structure in which the ends of the circular rings with spaced magnetic regulating magnets are connected. The cup-shaped rotor has a similar function to the traditional salient pole rotor, that is, it provides a channel with different magnetic resistance for the magnetic flux generated by the winding current, adjusts the stator magnetomotive force, and obtains the same harmonic flux density as the number of pole pairs of each winding on the opposite stator side, thereby coupling the two sets of stator windings with different pole pairs.

[0064] The mathematical model under the three-phase fixed coordinate system is as follows:

[0065] The voltage vector equation is:

[0066]

[0067] The flux vector equation is:

[0068]

[0069] The torque equation is:

[0070]

[0071] In the formula, R p and R s Represent the resistance of the excitation winding and the control winding respectively, and Respectively represent the current of the excitation winding and the control winding in the fixed coordinate system, ω p and ω s Represent the electrical angular frequency of the excitation winding and the control winding, L p and L s They represent the self-inductance of the field winding and the control winding, respectively, and p r is the number of rotor pole pairs, and They represent the current vectors of the excitation winding and the control winding in the fixed coordinate system, and They represent the frequency conversion of the excitation winding to the control winding and the control winding to the excitation winding, respectively. ps is the mutual inductance of the windings.

[0072] In step S2, according to the vector coordinate transformation rules, the dual dq coordinate system is used for decoupling, and the two sets of stator windings in the dual-stator modulation motor are transformed into two rotating coordinate systems with different angular velocities respectively.

[0073] Among them, see Figure 2 , the coordinate transformation rules of each vector are:

[0074] The α axis is aligned with the A phase axis of the excitation winding. Assuming the coordinate transformation angle of the excitation winding is θ, the coordinate transformation rules of each vector of the excitation winding are:

[0075]

[0076]

[0077] In the formula, represents the flux vector of the field winding in the rotating coordinate system, represents the current of the field winding in the rotating coordinate system;

[0078] Assume the coordinate transformation angle of the control winding is θ r -θ, then the coordinate transformation rules of each vector of the control winding are:

[0079]

[0080] In the formula, represents the flux vector of the field winding in the rotating coordinate system, Represents the current of the excitation winding in the rotating coordinate system.

[0081] In step S2, the mathematical model in the rotating coordinate system is as follows:

[0082] The flux equation of the excitation winding is:

[0083]

[0084] The control winding flux equation is:

[0085]

[0086] The voltage vector equation is:

[0087]

[0088] The torque equation is:

[0089]

[0090] In the formula, R p and R s Represent the resistance of the excitation winding and the control winding respectively, and denote the currents of the field winding and control winding in the fixed coordinate system, ω and ω respectively r Represent the electrical angular frequency and the rotor electrical angular frequency respectively, L p and L s They represent the self-inductance of the field winding and the control winding, respectively, and p r The number of rotor pole pairs, and They represent the current vectors of the excitation winding and the control winding in the rotating coordinate system respectively.

[0091] In step S3, the specific relationship is: according to the excitation winding flux equation in the rotating coordinate system, another form of the torque equation is obtained:

[0092]

[0093] In the formula, λ pd The formula represents the magnetic flux vector of d and q axes, i sq and i sd Represents the q-axis current and d-axis current in the rotating coordinate system.

[0094] Since the current frequencies of the two sets of stator windings of DSFMM are different, when transforming the vector equations of DSFMM from the fixed coordinate system to the rotating coordinate system, two different dq rotating coordinate systems are required to transform the excitation winding and the control winding respectively. The coordinate transformation angle of the excitation winding is θ, and the coordinate transformation angle of the control winding is θ r -θ, where θ r is the electrical angle of the rotor position, which is a known quantity in a motor equipped with a position sensor. In other words, as long as the excitation winding coordinate transformation angle is known and its vector is decoupled, the control winding coordinate transformation angle will also become a known quantity, and each vector will also be decoupled.

[0095] The DSFMM prototype was tested using a variable voltage and variable frequency speed control strategy, and the experimental control strategy is shown in Figure 3. The controller uses a back-to-back six-phase inverter to control the motor excitation winding and control winding current respectively.

[0096] The experimental results are as follows Figure 4 When 20Hz current is injected into the excitation winding and the control winding respectively, the rotor speed is 212rpm. When several currents of different frequencies are injected into the two sets of windings respectively, the rotor speed also changes accordingly.

[0097] Under the premise of allowing the VVVF open-loop control speed error, according to the experimental results, we can get the following relationship:

[0098] n r =60(f p +f s ) / p r (18)

[0099] Where n r is the DSFMM rotor speed, in r / min; f p is the excitation winding current frequency, in Hz; f s To control the winding current frequency, the unit is Hz. Formula (18) can be converted into two other formulas through unit conversion and equivalent transformation:

[0100] ω rm =(ω p +ω s ) / p r (19)

[0101] n r =60(f p +f s ) / p r (20)

[0102] In the formula, ω rm is the rotor angular velocity; ω p is the angular frequency of the field winding current, ωs To control the angular frequency of the winding current, the unit is rad / s; θ r is the rotor electrical angle, θ p is the electrical angle of the field winding, θ s To control the electrical angle of the winding, the unit is deg; through the VVVF experiment, it is determined that there is a relationship between the rotor position angle and the current frequency of the two sets of windings.

[0103] In step S3, the DC excitation current oriented vector control algorithm is:

[0104] Let the field winding coordinate transformation angle θ = 0, that is, the field winding equation is located in a fixed dq coordinate system, which means that a DC current is passed through the field winding, and the control winding coordinate transformation angle θ r -θ=θ r , that is, the control winding d-axis coincides with the rotor d-axis, and the control winding current frequency is the same as the rotor angular velocity, that is, the control winding vectors are all in the rotor coordinate system;

[0105] The permanent magnetic flux generated by the DC current in the excitation winding is modulated by the rotor and coupled with the magnetomotive force of the control winding. For this reason, the dual-stator modulation motor is controlled as a permanent magnet synchronous motor.

[0106] In step S3, the AC excitation current oriented vector control algorithm is:

[0107] Assume that the excitation winding coordinate transformation angle θ≠0, and the excitation winding dq coordinate system rotation angular velocity ω≠0rad / s, which means that AC current is passed through the excitation winding. Under AC excitation, the d-axis of the excitation winding coordinate system is controlled to coincide with the current vector, so that the variables in the excitation winding and control winding equations are DC quantities at any time.

[0108] In step S4, the control switching method is: when the speed reaches the switching value, according to the pre-collected speed and motor parameters, the control algorithm to be switched performs reverse operation to obtain control parameters matching the current speed, and then inputs the control parameters into the control algorithm to be switched, and the control algorithm to be switched takes over the control algorithm in control to control the dual-stator modulation motor.

[0109] Next, the DSFMM model is studied and established on the Simulink platform of Matlab, and the stator current vector-oriented control algorithm model under DC and AC excitation is built based on the motor model to verify the vector-oriented control algorithm proposed in this application.

[0110] The variable parameters in the model are defined as follows: Control winding pole pair number p s is 5, the number of pole pairs of the excitation winding is p p is 6, the number of rotor pole pairs p r=11, control winding resistance R s is 0.88, the excitation winding resistance R p is 0.1, and the control winding self-inductance L s is 4.5, the self-inductance of the excitation winding L p is 6, the winding mutual inductance L ps is 1.2, and the moment of inertia J is 0.008.

[0111] Under DC excitation, the given speed of DSFMM increases suddenly from 55rpm to 110rpm, and switches from DC excitation to AC excitation. The actual speed tracking response waveform is as follows: Figure 5 shown.

[0112] In this simulation, the given excitation winding current ipd_ref=4A, ipq_ref=0A. Figure 5 It can be seen that after the given speed changes in a step of 0.4s, the actual speed quickly reaches a stable state after a small overshoot. The rapid stability due to a small overshoot indicates that the motor runs well under AC excitation.

[0113] The above are only embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A hybrid control switching method for a dual-stator modulation motor under complex environment, the steps of which are: Step 1: Obtain a mathematical model of the dual-stator modulation motor in a natural coordinate system; Step 2: Perform coordinate transformation on the mathematical model obtained in step 1 to obtain a mathematical model in a rotating coordinate system; Step 3: According to the specific relationship between the coordinate transformation angles of the excitation winding and the control winding in the rotating coordinate system, two current oriented vector control algorithms, DC excitation and AC excitation, which can be independently controlled and operated, are determined; Step 4: Use a DC excitation current oriented vector control algorithm to control the dual-stator modulation motor at low speed, and use an AC excitation current oriented vector control algorithm to control the dual-stator modulation motor at medium and high speed. According to the specific relationship obtained, control switching between DC excitation and AC excitation is performed to achieve hybrid control of the dual-stator modulation motor under different excitations.

2. The hybrid control switching method of a dual-stator modulation motor under complex environment according to claim 1 is characterized in that: In the step 1, the mathematical model in the three-phase fixed coordinate system is as follows: The voltage vector equation is: The flux vector equation is: The torque equation is: In the formula, R p and R s Represent the resistance of the excitation winding and the control winding respectively, and Respectively represent the current of the excitation winding and the control winding in the fixed coordinate system, ω p and ω s Represent the electrical angular frequency of the excitation winding and the control winding, L p and L s They represent the self-inductance of the field winding and the control winding, respectively, and p r is the number of rotor pole pairs, and They represent the current vectors of the excitation winding and the control winding in the fixed coordinate system, and They represent the frequency conversion of the excitation winding to the control winding and the control winding to the excitation winding, respectively. ps is the mutual inductance of the windings.

3. The hybrid control switching method of a dual-stator modulation motor under complex environment according to claim 1 is characterized in that: In the step 2, according to the vector coordinate transformation rules, the dual dq coordinate system is used for decoupling, and the two sets of stator windings in the dual-stator modulation motor are transformed into two rotating coordinate systems with different angular velocities respectively.

4. The hybrid control switching method of a dual-stator modulation motor under complex environment according to claim 1 is characterized in that: The coordinate transformation rules of each vector are: Assuming the field winding coordinate transformation angle is θ, the coordinate transformation rules of each vector of the field winding are: In the formula, represents the flux vector of the field winding in the rotating coordinate system, represents the current of the field winding in the rotating coordinate system; Assume the coordinate transformation angle of the control winding is θ r -θ, then the coordinate transformation rules of each vector of the control winding are: In the formula, represents the flux vector of the field winding in the rotating coordinate system, Represents the current of the excitation winding in the rotating coordinate system.

5. The hybrid control switching method of a dual-stator modulation motor under complex environment according to claim 1 is characterized in that: In step 2, the mathematical model in the rotating coordinate system is as follows: The flux equation of the excitation winding is: The control winding flux equation is: The voltage vector equation is: The torque equation is: In the formula, R p and R s Represent the resistance of the excitation winding and the control winding respectively, and denote the currents of the field winding and control winding in the fixed coordinate system, ω and ω respectively r Represent the electrical angular frequency and the rotor electrical angular frequency respectively, L p and L s They represent the self-inductance of the field winding and the control winding, respectively, and p r The number of rotor pole pairs, and They represent the current vectors of the excitation winding and the control winding in the rotating coordinate system respectively.

6. The hybrid control switching method of a dual-stator modulation motor under complex environment according to claim 1 is characterized in that: In step 3, the specific relationship is: according to the magnetic flux equation of the excitation winding in the rotating coordinate system, another form of the torque equation is obtained: In the formula, λ pd The formula represents the magnetic flux vector of d and q axes, i sq and i sd Represents the q-axis current and d-axis current in the rotating coordinate system.

7. The hybrid control switching method of a dual-stator modulation motor under complex environment according to claim 1 is characterized in that: In step 3, the DC excitation current oriented vector control algorithm is: Let the field winding coordinate transformation angle θ = 0, that is, the field winding equation is located in a fixed dq coordinate system, which means that a DC current is passed through the field winding, and the control winding coordinate transformation angle θ r -θ=θ r , that is, the control winding d-axis coincides with the rotor d-axis, and the control winding current frequency is the same as the rotor angular velocity, that is, the control winding vectors are all in the rotor coordinate system; The permanent magnetic flux generated by the DC current in the excitation winding is modulated by the rotor and coupled with the magnetomotive force of the control winding. For this reason, the dual-stator modulation motor is controlled as a permanent magnet synchronous motor.

8. The hybrid control switching method of a dual-stator modulation motor under complex environment according to claim 1, characterized in that: In step 3, the AC excitation current oriented vector control algorithm is: Assume that the excitation winding coordinate transformation angle θ≠0, and the excitation winding dq coordinate system rotation angular velocity ω≠0rad / s, which means that AC current is passed through the excitation winding. Under AC excitation, the d-axis of the excitation winding coordinate system is controlled to coincide with the current vector, so that the variables in the excitation winding and control winding equations are DC quantities at any time.

9. The hybrid control switching method of a dual-stator modulation motor under complex environment according to claim 1, characterized in that: In the step four, the control switching method is: when the speed reaches the switching value, according to the pre-collected speed and motor parameters, the control algorithm to be switched performs reverse operation to obtain control parameters matching the current speed, and then inputs the control parameters into the control algorithm to be switched, and the control algorithm to be switched takes over the control algorithm in control to control the dual-stator modulation motor.

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