A motor, a stator resistance estimation method, a control method and a system

Abstract

The present invention discloses a motor, a stator resistance estimation method, a control method and a system. Among them, the present invention optimizes the structure of the motor body, and alternately arranges the positions of the DC excitation coils and the AC armature coils on two adjacent stator teeth. Thus, by introducing the alternately arranged winding structure, the heat dissipation conditions of the excitation winding and the armature winding are made uniform. Furthermore, a current distribution strategy is proposed to make the copper losses generated by the excitation winding and the armature winding equal, solving the problem of temperature balance between the armature winding and the excitation winding of the motor. Furthermore, under the condition that the heating and heat dissipation conditions are the same, there is a fixed proportional relationship between the excitation resistance and the stator resistance. Based on this principle, an on-line identification method for the stator resistance is proposed, overcoming the technical defects that the traditional identification method is affected by the nonlinearity of the inverter and other parameter errors. Finally, the accurate estimation of the motor speed and the rotor position is realized, improving the reliability and stability of the motor control.

Description

Technical Field

[0001] The present invention belongs to the technical field of motors, and particularly relates to a motor, a stator resistance estimation method, a control method and a system, and in particular provides a variable reluctance motor with an alternating excitation coil and armature coil. Background Art

[0002] A variable reluctance motor is a new type of brushless synchronous motor with stator excitation. It has the advantages of no rare earth in the rotor, simple structure, low cost, high reliability, adjustable air-gap magnetic field, wide speed regulation range, and small torque ripple. It has good application prospects in the fields of electric vehicles, mining equipment, aviation power generation, or industrial automation. The field-oriented control of a synchronous motor requires accurate rotor position. Mechanical position sensors have the disadvantages of low reliability, high cost, and electromagnetic interference, and sometimes it is even impossible to install them. In order to reduce the negative impact of the position sensor on the control system, it is necessary to develop sensorless control technology.

[0003] On the one hand, the back electromotive force of the motor contains rotor position information. The full-order observer based on the back electromotive force is a classic sensorless control technology. By sampling the motor voltage and current, the rotor position and speed information are estimated through the motor mathematical model, and it has excellent performance. However, there are still some problems in its application in variable reluctance motors: both the armature winding and the excitation winding are in the stator slots, and the resistance change is more serious. When the heat generation and heat dissipation capabilities of the two sets of windings are different, the temperature difference between the two sets of windings will be very large, which may damage the winding insulation and reduce the life of the motor. Therefore, achieving temperature balance between the armature winding and the excitation winding is a technical problem that needs to be overcome in this field.

[0004] On the other hand, when the motor operates at low speed, due to the very small induced electromotive force, the mismatch of the stator resistance will cause a large position estimation error, resulting in system instability and deterioration of control performance. This hinders its application at low speeds. Therefore, in order to achieve stable operation at low speeds, accurate estimation of the stator resistance is of great significance.

[0005] To reduce the sensitivity to stator resistance, existing methods mainly include the thermal model method, the DC injection method, the resistance adaptive method, etc. In addition, the thermal model method requires offline testing of parameters such as thermal resistance, heat capacity, and heat dissipation coefficient, which is cumbersome; the DC injection method will cause certain torque ripple. Among these methods, the resistance adaptive method based on the full-order observer has received extensive attention, but this method is sensitive to the nonlinearity of the inverter and requires accurate other parameters except the stator resistance, such as the DC inductance, the quadrature-axis inductance, the permanent magnet flux linkage, etc. However, in practice, these three parameters also change with the load or temperature. When the inverter nonlinear compensation is inaccurate, or other motor parameters are inaccurate, the stator resistance estimated by the traditional stator resistance adaptive method has a large error, resulting in an observer position error, and even causing the observer to be unstable and unable to work properly. Therefore, the influence of the inverter nonlinearity and other parameter errors on the stator resistance estimation accuracy is also a difficult problem to overcome in this field.

[0006] Therefore, for the body design of the variable-flux reluctance motor and its sensorless control technology, how to achieve the temperature balance between the armature winding and the field winding of the motor is the most urgent problem to be solved in the present invention. Summary of the Invention

[0007] In order to overcome the technical obstacle of the temperature balance between the armature winding and the field winding of the motor and solve this technical problem, the technical solution of the present invention provides a motor, a stator resistance estimation method, a control method and a system, specifically an alternating variable-reluctance motor with an excitation coil and an armature coil. By optimizing the structure of the motor body and adopting a radial inner and outer alternating arrangement structure of a DC excitation coil and an AC armature coil, the heat dissipation capabilities of the DC excitation winding and the AC armature winding are made the same, and by controlling the copper losses of the excitation winding and the armature winding, the temperatures of the excitation winding and the armature winding are made the same, overcoming the problem of uneven temperature distribution of the two sets of windings in the traditional winding structure. On the other hand, on the basis of optimizing the motor body structure, a new stator resistance estimation method and a motor control method are proposed, overcoming the technical defects of the traditional stator resistance identification method affected by the inverter nonlinearity and other parameter errors, not requiring motor parameters such as the direct-axis inductance, the quadrature-axis inductance, and the mutual inductance, not depending on the speed and the rotor position, and having higher identification accuracy and less calculation amount.

[0008] For this reason, the present invention provides the following technical solutions:

[0009] On the one hand, a motor with an alternating excitation coil and armature coil provided by the present invention is a variable-reluctance motor, which is provided with a stator and a rotor nested in a concentric and coaxial manner, both the stator and the rotor are salient pole structures, and the stator is provided with stator teeth facing the rotor;

[0010] Among them, each of the stator teeth is provided with a DC excitation coil and an AC armature coil, and the positions of the DC excitation coils and the AC armature coils on two adjacent stator teeth are arranged alternately, that is, on one stator tooth, the DC excitation coil is radially close to the outer side of the stator, and the AC armature coil is radially close to the inner side of the stator; on the adjacent stator tooth, the DC excitation coil is radially close to the inner side of the stator, and the AC armature coil is radially close to the outer side of the stator.

[0011] And the reference values of the direct-axis current, quadrature-axis current and excitation current in the variable reluctance motor are distributed according to the principle that the copper losses of the DC excitation winding of the whole motor and the AC armature winding of the whole motor are equal.

[0012] In the traditional non-alternating winding form, all the DC excitation coils are on the outside and all the AC armature coils are on the inside. The heat transfer path of the DC excitation coil is shorter, the heat dissipation is faster, and its thermal resistance is smaller. The heat transfer path of the AC armature coil is longer, the heat dissipation is slower, and its thermal resistance is larger, so the heat dissipation capabilities of the two coils are different. According to the equivalent thermal circuit principle of the motor, after the DC excitation coil and the AC armature coil are arranged alternately in the technical solution of the present invention, the thermal resistances and heat capacities of the DC excitation coil and the AC armature coil are equal. In order to make the heat dissipation capabilities of the excitation winding and the armature winding of the whole motor the same, the excitation coil and the armature coil are arranged alternately in the technical solution of the present invention, so that the total length of the heat transfer path is equal, and the heat dissipation capabilities are the same. Also, because the technical solution of the present invention actively controls the copper losses of the DC excitation winding and the AC armature winding to be equal, their heating powers are equal. When the heating power and the heat dissipation capability are equal, the temperatures of the two sets of windings are equal, and there is a fixed ratio between their resistance values.

[0013] The technical solution of the present invention distributes the current reference values according to this method, that is, the copper losses of the DC excitation winding and the AC armature winding are equal, and there is:

[0014] ;

[0015] ;

[0016] In the formula, , are the copper losses of the AC armature winding and the DC excitation winding respectively, , are the estimated values of the stator resistance and the excitation resistance respectively, , are the quadrature-axis current value and the excitation current value respectively.

[0017] Let , and we get

[0018] ;

[0019] Let , the following can be obtained:

[0020] ;

[0021] Based on the above reasoning, it is defined that the quadrature-axis current reference value and the field current reference value satisfy:

[0022] ;

[0023] In the formula, is the field current reference value, is the quadrature-axis current reference value, represents the theoretical ratio of the stator resistance to the field resistance; the direct-axis current reference value is set to 0.

[0024] Among them, the saliency ratio of the variable reluctance motor is 0 or close to 0, that is, the corresponding direct-axis current reference value is set to 0.

[0025] Preferably, both the DC field winding and the AC armature winding are concentrated windings.

[0026] Preferably, the quadrature-axis current reference value is calculated according to the electromagnetic torque reference value output by the speed-loop PI regulator, specifically as follows:

[0027] ;

[0028] In the formula, is the electromagnetic torque set value output by the speed-loop proportional-integral regulator, is the field current sampling value, is the number of pole pairs of the motor, is the mutual inductance between the AC armature winding and the DC field winding.

[0029] Preferably, the stator has 12 teeth and the rotor has 10 rotor teeth.

[0030] On the other hand, a stator resistance estimation method based on the above motor provided by the present invention, after distributing the reference values of the direct-axis current, quadrature-axis current, and field current in the variable reluctance motor according to the principle that the copper losses of the DC field winding and the AC armature winding of the entire motor are equal, the method includes:

[0031] Obtain the field voltage set value and the field current sampling value of the variable reluctance motor;

[0032] Calculate the field resistance by using the field voltage set value and the field current sampling value;

[0033] Multiply the field resistance by a fixed coefficient Obtain the estimated stator resistance, The theoretical ratio of the represented stator resistance to the field resistance is determined by the number of turns and the number of coils.

[0034] Preferably, the field resistance is obtained based on the voltage equation of the field branch at steady state and embedded with a first-order low-pass filter. The calculation formula is:

[0035] ;

[0036] In the formula, represents the reference value of the field voltage at the current k moment, that is, the given value of the field voltage, represents the sampled value of the field current at the current k moment, is the estimated value of the field resistance at the current k moment, represents the estimated value of the field resistance at the k-1 moment, represents the bandwidth of the first-order low-pass filter of the field resistance, is the sampling period.

[0037] Thirdly, a motor control method based on the above stator resistance estimation method provided by the present invention inputs the estimated stator resistance into an observer. The method includes:

[0038] Obtain the sampled values of the dq-axis currents and the voltage reference values of the variable reluctance motor in the rotating coordinate system;

[0039] Input the sampled value of the field current and the sampled values of the dq-axis currents and the voltage reference values into the observer to obtain the estimated values of the dq-axis currents;

[0040] Calculate the current estimation error of the dq-axis, and input the current estimation error into the speed and rotor position estimation module to obtain the estimated value of the speed and the estimated value of the rotor position angle. Then, feedback the obtained estimated value of the speed, the estimated value of the rotor position angle, and the estimated value of the stator resistance to the observer for the speed and position estimation at the next moment;

[0041] Among them, the current estimation error of the dq-axis is the difference between the current estimated value and the current sampled value.

[0042] Fourthly, a control system based on the above motor control method provided by the present invention includes at least:

[0043] A current distribution module for distributing the reference values of the direct-axis current, the quadrature-axis current, and the field current in the variable reluctance motor based on the principle that the copper losses of the DC field winding of the entire motor and the AC armature winding of the entire motor are equal;

[0044] A field resistance and stator resistance estimation module for first calculating the field resistance and then multiplying the field resistance by a fixed coefficient Obtain the estimated stator resistance;

[0045] A sampling module for obtaining the current sampling values and voltage reference values of the dq axes in the rotating coordinate system of the variable reluctance motor;

[0046] An observer for estimating the estimated current values of the dq axes;

[0047] A rotational speed and rotor position estimation module for obtaining the estimated rotational speed value and the estimated rotor position angle value by using the current estimation error of the dq axes;

[0048] Wherein, the estimated rotational speed value, the estimated rotor position angle value, and the estimated stator resistance value are fed back to the observer for the rotational speed and position estimation at the next moment; the current estimation error of the dq axes is the difference between the estimated current value and the current sampling value.

[0049] Fifthly, a computer-readable storage medium provided by the present invention stores a computer program, and the computer program is called by a processor to implement:

[0050] Distribute the reference values of the direct-axis current, quadrature-axis current, and field current in the variable reluctance motor according to the principle that the copper losses of the DC exciting winding of the entire motor and the AC armature winding of the entire motor are equal;

[0051] First calculate the field resistance, and then multiply the field resistance by a fixed coefficient To obtain the estimated stator resistance and feed it back to the observer;

[0052] Obtain the current sampling values and voltage reference values of the dq axes in the rotating coordinate system of the variable reluctance motor;

[0053] Input the field current sampling value, the current sampling values of the dq axes, and the voltage reference value into the observer to obtain the estimated current values of the dq axes;

[0054] Calculate the current estimation error of the dq axes, input the current estimation error into the rotational speed and rotor position estimation module to respectively obtain the estimated rotational speed value and the estimated rotor position angle value, and then feed back the obtained estimated rotational speed value, the estimated rotor position angle value, and the estimated stator resistance value to the observer for the rotational speed and position estimation at the next moment; wherein, the current estimation error of the dq axes is the difference between the estimated current value and the current sampling value.

[0055] Advantageous effects

[0056] Compared with the prior art, the technical solution of the present invention has the following advantageous effects:

[0057] 1. The variable reluctance motor provided by the technical solution of the present invention introduces an alternately arranged winding structure, which equalizes the heat dissipation conditions of the field winding and the armature winding, enables the heat dissipation capabilities of the armature winding and the field winding to be the same, avoids the problem of uneven heat dissipation, and further combines an equal copper loss current distribution module to ensure the temperature balance of the field winding and the armature winding, overcomes the problem of uneven temperature distribution of the two sets of windings in the traditional winding structure of the motor, avoids problems such as insulation burnout and short circuit of the coil caused by excessive temperature of a certain winding, and improves the service life of the motor.

[0058] 2. For the motor and control method of the present invention, since the field resistance and the stator resistance can be accurately identified, the position estimation accuracy of the observer is improved, the problem of excessive current caused by position error is solved, the motor can stably operate in the high-efficiency region, the efficiency of the system is improved, and important improvements are made in terms of high efficiency and energy saving.

[0059] 3. The present invention can accurately estimate the field resistance and the stator resistance. The proposed method overcomes the technical defect that the traditional stator resistance identification method is affected by the nonlinearity of the inverter and other parameter errors, does not require motor parameters such as direct-axis inductance, quadrature-axis inductance, and mutual inductance, is independent of the rotational speed and rotor position, and has higher identification accuracy and less calculation amount. Among them, the stator resistance proposed by the technical solution of the present invention is essentially obtained by dividing the field voltage reference value by the field current sampling value and multiplying by the fixed coefficients of the stator resistance and the field resistance obtained, , obviously, the entire calculation formula does not require motor parameters such as direct-axis inductance, quadrature-axis inductance, and mutual inductance.

[0060] 4. After the stator resistance identified by the present invention is input into the observer, the parameter robustness of the observer is improved, the low-speed stable operation range of the observer is increased, the low-speed load-carrying capacity is improved, the accurate estimation of the motor speed and rotor position is realized, and the reliability and stability of the motor control method are ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 is a schematic diagram of the coils of the DC field winding and the AC armature winding proposed by the present invention.

[0062] Figure 2 is a schematic diagram of the coils of the traditional DC field winding and the AC armature winding.

[0063] Figure 3 is a schematic diagram of the control principle of the method of the embodiment of the present invention.

[0064] Figure 4 is a schematic diagram of the principle of the current distribution module proposed by the embodiment of the present invention.

[0065] Figure 5Internal schematic diagram of the excitation resistance and stator resistance estimation module for the method of the embodiment of the present invention.

[0066] Figure 6 Internal schematic diagram of the observer for the method of the embodiment of the present invention.

[0067] Figure 7 Schematic diagram of the speed and rotor position estimation module proposed in the embodiment of the present invention.

[0068] Wherein: 1, DC excitation coil; 2, AC armature coil; 3, stator; 4, rotor. Detailed implementation manners

[0069] A motor, a stator resistance estimation method, a control method and a system provided by the technical solution of the present invention specifically propose a variable reluctance motor with an alternating excitation coil and armature coil. By optimizing the structure of the motor body and adopting a new winding structure with the DC excitation coil and AC armature coil arranged alternately radially inside and outside, the heat dissipation conditions of the excitation winding and the armature winding are made uniform, avoiding the problem of uneven heat dissipation. Moreover, a current distribution strategy is proposed to make the copper losses generated by the excitation winding and the armature winding equal. In addition, when the heat generation and heat dissipation conditions are the same, there is a fixed proportional relationship between the excitation resistance and the stator resistance. Based on this principle, an on-line identification method for the stator resistance is proposed. The excitation resistance and stator resistance obtained by on-line identification can realize the temperature estimation of the excitation winding and the armature winding, and perform thermal protection on the variable reluctance motor, avoiding the motor from being burned out due to overheating. The following will further illustrate the present invention in conjunction with embodiments.

[0070] Different from Figure 2 the traditional motor body structure shown, a variable reluctance motor with an alternating excitation coil and armature coil provided by the technical solution of the present invention is as Figure 1 shown. It includes at least a DC excitation coil 1, an AC armature coil 2, a stator 3, and a rotor 4. Both the stator 3 and the rotor 4 are salient pole structures and are laminated by silicon steel sheets and nested together in a concentric and coaxial manner. The stator 3 is provided with stator teeth facing the rotor 4, and each stator tooth is provided with a DC excitation coil 1 and an AC armature coil 2. Both the DC excitation winding and the AC armature winding are concentrated windings, and the positions of the DC excitation coils 1 and the AC armature coils 2 on adjacent two stator teeth are arranged alternately. For example, on the first tooth, the DC excitation coil 1 is radially close to the outside of the stator 3, and the AC armature coil is close to the inside of the stator 3. On the second tooth, the DC excitation coil 1 is radially close to the inside of the stator 3, and the AC armature coil is close to the outside of the stator 3. The variable reluctance motor provided in Embodiment 1 of the present invention has a total of 12 stator teeth and 10 rotor teeth, and includes 12 DC excitation coils 1 and 12 AC armature coils 2. In other feasible embodiments, there is no such restriction.

[0071] By optimizing the structure of the motor body, the present invention enables the DC excitation winding and the AC armature winding to have the same heat dissipation capacity, effectively improving the problem of winding insulation burnout caused by uneven temperature during motor operation and extending the service life of the motor. In order to achieve the same heat generation capacity for the two sets of windings, based on the principle of equal copper losses in the armature winding and the excitation winding, the direct-axis current, quadrature-axis current, and excitation current are distributed according to the electromagnetic torque reference value output by the speed-loop PI regulator. Thus, the heat dissipation capacity and heat generation capacity of the two sets of windings are truly made the same, and the temperatures of the excitation resistance and the stator resistance are made consistent.

[0072] Among them, the present invention preferably adopts the following technical means to distribute the direct-axis current, quadrature-axis current, and excitation current:

[0073] As Figure 4 shown, the distribution of the direct-axis current, quadrature-axis current, and excitation current is realized through the Figure 4 current distribution module. Based on the principle of equal copper losses in the excitation winding and the armature winding, the reference value of the excitation current and the reference value of the quadrature-axis current need to satisfy the condition: . In the variable reluctance motor, the saliency ratio is basically 0, and the reluctance torque does not need to be utilized. Therefore, the reference value of the direct-axis current adopts a simple =0 control strategy.

[0074] Among them, the reference value of the quadrature-axis current is calculated based on the electromagnetic torque reference value output by the speed-loop PI regulator, specifically as follows:

[0075] ;

[0076] In the formula, is the electromagnetic torque set value output by the speed-loop proportional-integral regulator, is the set value (reference value) of the quadrature-axis current, is the number of pole pairs of the motor, is the mutual inductance between the AC armature winding and the DC excitation winding, is the sampled excitation current, is the set value (reference value) of the excitation current, is the set value (reference value) of the direct-axis current.

[0077] In some embodiments, the technical solution of the present invention also provides a stator resistance estimation method based on the above motor. After distributing the direct-axis current, quadrature-axis current, and excitation current in the variable reluctance motor with equal copper losses in the DC excitation winding and the AC armature winding, the stator resistance estimation method includes:

[0078] S1: Obtain the given value of the excitation voltage and the sampled value of the excitation current of the motor;

[0079] S2: Calculate the excitation resistance by using the given value of the excitation voltage and the sampled value of the excitation current;

[0080] S3: Multiply the excitation resistance by a fixed coefficient to obtain the estimated stator resistance, where the theoretical ratio of the represented stator resistance to the excitation resistance is determined by the number of turns and the number of coils.

[0081] As Figure 5 shown, the excitation resistance in this embodiment is calculated from the steady-state voltage equation of the excitation branch and an order-1 low-pass filter is embedded to make the identification result smoother. Since there is a fixed proportional relationship between the stator resistance and the excitation motor in the present invention, the stator resistance can be obtained by multiplying the excitation resistance by a fixed coefficient as such.

[0082] In the steady state, the voltage equation of the excitation branch is , and according to this equation, the excitation resistance can be directly calculated as:

[0083] . To make the estimated excitation resistance smoother, an order-1 low-pass filter is embedded, and its expression is:

[0084] ;

[0085] wherein, represents the reference value of the excitation voltage at the current k-th moment, represents the sampled value of the excitation current at the current k-th moment, is the estimated value of the excitation resistance at the current k-th moment, represents the estimated value of the excitation resistance at the previous sampling period k - 1 moment, represents the bandwidth of the order-1 low-pass filter of the excitation resistance, generally selected as , is the sampling period. represents the integrator, represents the theoretical ratio of the stator resistance to the excitation resistance, which is determined by the number of turns and the number of coils, and is 1 / 3 in the present invention, is the estimated value of the stator resistance.

[0086] It should be understood that the stator resistance estimation method proposed by the technical solution of the present invention effectively overcomes the technical defects of the traditional stator resistance identification method affected by the non-linearity of the inverter and other parameter errors. It does not require motor parameters such as direct-axis inductance, quadrature-axis inductance, and mutual inductance, and does not depend on the rotational speed and rotor position. It has higher identification accuracy and less computational complexity. After obtaining the stator resistance estimation value, it can be applied to the motor control method to achieve motor control. It should be noted that after obtaining the stator resistance estimation value, how to apply it in the motor control method is not specifically limited in the present invention, and any kind of motor control method using the stator resistance estimation value is feasible and falls within the protection scope of the present invention.

[0087] In some embodiments, as Figure 3 shown, the motor control is realized according to the following technical idea:

[0088] S21: Obtain the current sampling values and voltage reference values of the dq axes of the motor in the rotating coordinate system;

[0089] S22: Input the excitation current sampling value, the current sampling values of the dq axes, the voltage reference value, and the rotational speed estimation value into the observer to obtain the current estimation values of the dq axes;

[0090] S23: Calculate the current estimation errors of the dq axes, and input the current estimation errors into the rotational speed and rotor position estimation module to respectively obtain the rotational speed estimation value and the rotor position angle estimation value. Then, feedback the obtained rotational speed estimation value, rotor position angle estimation value, and the previously obtained stator resistance estimation value to the observer for the rotational speed and position estimation at the next moment; wherein, the current estimation error of the dq axes is the difference between the corresponding current estimation value and the current sampling value.

[0091] It should be understood that as Figure 3 shown, based on the principle of vector control, measure the phase current i a , i b in the variable reluctance motor, and obtain the direct-axis current and quadrature-axis current through coordinate transformation. These two currents are sent to the dq current loop as feedback values, and together with the given values, they are sent into the proportional-integral module (PI module) of the current loop. The PI adjustment output obtains the dq-axis voltages u d , u q . Then it is sent to the SVPWM space vector pulse width modulation module to control the on-off of the IGBTs in the three-phase inverter to achieve the control of the armature circuit. In the excitation circuit, sample the excitation current and then send it to the excitation current loop as a feedback value. Together with the excitation current given value , it is sent into the proportional-integral module (PI module) of the excitation current loop, and the PI adjustment output obtains the excitation voltage reference value Then it is sent to the PWM pulse width modulation module to control the on / off of the IGBTs in the H-bridge inverter, thereby realizing the control of the excitation circuit. It should be noted that this part of the control process is the prior art in this field, so it will not be described in detail herein.

[0092] To more clearly show the observer and the estimation schemes for the rotational speed and rotor position, examples will be given below. However, the technical solution of the present invention is not limited to the following mathematical models.

[0093] Regarding the observer:

[0094] As Figure 6 shown, first calculate the direct-axis flux and the quadrature-axis flux through the direct-axis and quadrature-axis flux estimation equations, and then calculate the estimated direct-axis and quadrature-axis currents .

[0095] ;

[0096] ;

[0097] In the formula, , are the estimated direct-axis and quadrature-axis fluxes respectively, is the estimated value of the currents on the d and q axes in the rotating coordinate system, and are the voltage reference values and current sampling values of the motor on the d and q axes in the rotating coordinate system; is the sampling value of the excitation current, and are the estimated inductances of the d and q axes, is the estimated stator resistance, is the estimated mutual inductance value between the armature winding and the excitation winding of the motor, is the estimated rotational speed value, are all the gains of the full-order observer selected in this embodiment.

[0098] Among them:

[0099] ;

[0100] Among them:

[0101] , , are all intermediate variables, which are respectively:

[0102] , , where b and c are positive numbers.

[0103] Estimated speed and rotor position estimation module:

[0104] As shown in Figure 7 , subtract the estimated quadrature-axis current from the quadrature-axis current in the rotating coordinate system to obtain the current error . The estimated speed is obtained through a PI regulator, and the estimated angle is obtained by integrating the estimated speed.

[0105] ;

[0106] Among them, is the estimated rotor angle, is the proportional parameter of speed adaptation, is the integral parameter of speed adaptation.

[0107] , among which, is the bandwidth of speed adaptation, generally selected as , is an intermediate variable, , are the estimated values of d-axis and q-axis inductances respectively, is the estimated value of mutual inductance, is the sampled value of d-axis current, is the sampled value of field current.

[0108] In some embodiments, a control system based on the above motor control method provided by the present invention at least includes: a current distribution module, an excitation resistance and stator resistance estimation module, a sampling module, an observer, a speed and rotor position estimation module, and a speed loop.

[0109] The current distribution module is used to distribute the direct-axis current, quadrature-axis current, and field current in the variable reluctance motor with equal copper losses in the DC excitation coil and AC armature coil; the excitation resistance and stator resistance estimation module is connected to the observer, and is used to first calculate the excitation resistance, and then multiply the excitation resistance by a fixed coefficient to obtain the estimated stator resistance, and then transmit the estimated stator resistance to the observer; the sampling module is connected to the observer, and is used to obtain the current sampling values and voltage reference values of the dq axes of the motor in the rotating coordinate system, and transmit them to the observer; the observer is used to estimate the current estimated values of the dq axes and transmit them to the speed and rotor position estimation module; the speed and rotor position estimation module is used to obtain the speed estimated value and rotor position angle estimated value by using the current estimation error of the dq axes, and transmit them to the observer and the speed loop, and the speed loop calculates and determines the electromagnetic torque given value and transmits it to the current distribution module for distributing the direct-axis current, quadrature-axis current, and field current in the variable reluctance motor.

[0110] Among them, the estimated rotational speed value, the estimated rotor position angle value, and the estimated stator resistance value are fed back to the observer for the rotational speed and position estimation at the next moment; the current estimation error of the dq axes is the difference between the current estimated value and the current sampled value.

[0111] It should be noted that for the specific implementation process of each module, please refer to the content of the above method and will not be elaborated here. It should be understood that the above division of functional modules is only a division of logical functions. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. At the same time, the above integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

[0112] In some embodiments, a computer-readable storage medium provided by the present invention stores a computer program, and the computer program is called by a processor to implement:

[0113] Distribute the direct-axis current, quadrature-axis current, and excitation current in the variable reluctance motor so that the copper losses of the DC excitation coil and the AC armature coil are equal;

[0114] First calculate the excitation resistance, and then multiply the excitation resistance by a fixed coefficient to obtain the estimated stator resistance, and feed it back to the observer;

[0115] Obtain the current sampled values and voltage reference values of the dq axes of the variable reluctance motor in the rotating coordinate system;

[0116] Input the excitation current sampled value, the current sampled values of the dq axes, and the voltage reference value into the observer to obtain the current estimated values of the dq axes;

[0117] Calculate the current estimation error of the dq axes, and input the current estimation error into the rotational speed and rotor position estimation module to respectively obtain the estimated rotational speed value and the estimated rotor position angle value, and then feed back the obtained estimated rotational speed value, estimated rotor position angle value, and estimated stator resistance value to the observer for the rotational speed and position estimation at the next moment; among them, the current estimation error of the dq axes is the difference between the current estimated value and the current sampled value.

[0118] For the specific implementation process of each step, please refer to the description of the foregoing method.

[0119] The readable storage medium is a computer-readable storage medium, which may be an internal storage unit of the software and hardware device described in any of the foregoing embodiments, such as the hard disk or memory of the controller. The readable storage medium may also be an external storage device of the controller, such as a plug-in hard disk equipped on the controller, a Smart Media Card (SMC), a Secure Digital (SD) card, a Flash Card, etc. Further, the readable storage medium may also include both the internal storage unit of the controller and the external storage device. The readable storage medium is used to store the computer program and other programs and data required by the controller. The readable storage medium may also be used to temporarily store the data that has been output or is to be output.

[0120] Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions to enable a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The foregoing readable storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disc.

[0121] Those skilled in the art should understand that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-readable storage media (including but not limited to disk memories, CD-ROMs, optical memories, etc.) that contain computer-usable program code. The present application is a device that generates, according to the flowchart of the method, device (system), and computer program product according to the embodiments of the present application, and instructions executed by a processor to implement the functions specified in one or more processes of the flowchart and / or one or more boxes of the block diagram. These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device that implements the functions specified in one or more processes of the flowchart and / or one or more boxes of the block diagram. These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes of the flowchart and / or one or more boxes of the block diagram.

[0122] It should be emphasized that the examples described in the present invention are illustrative rather than restrictive. Therefore, the present invention is not limited to the examples described in the specific embodiments. Any other embodiments obtained by those skilled in the art based on the technical solutions of the present invention, whether modified or replaced, as long as they do not depart from the spirit and scope of the present invention, also belong to the protection scope of the present invention.

Claims

1. A motor with alternating field coils and armature coils, characterized in that: The motor is a variable reluctance motor, provided with a stator and a rotor nested in a concentric and coaxial manner, the stator and the rotor are both salient pole structures, and the stator is provided with stator teeth facing the rotor; Wherein, each of the stator teeth is provided with a DC excitation coil and an AC armature coil, and the DC excitation coils and the AC armature coils on two adjacent stator teeth are arranged alternately, that is, the DC excitation coil on one stator tooth is radially close to the outer side of the stator, and the AC armature coil is radially close to the inner side of the stator, and the DC excitation coil on adjacent stator teeth is radially close to the inner side of the stator, and the AC armature coil is radially close to the outer side of the stator; The reference values ​​of the direct-axis current, quadrature-axis current and excitation current in the variable reluctance motor are allocated based on the principle that the copper loss of the direct-axis excitation winding of the entire motor and the alternating-axis armature winding of the entire motor are equal; The copper loss of the DC excitation winding is equal to the copper loss of the AC armature winding, so: ； ； In the formula, , are the copper losses of the AC armature winding and the DC field winding, respectively. , are the estimated values ​​of stator resistance and field resistance respectively, , are the quadrature axis current value and the excitation current value respectively; make ,get: ； exist: ; It is further inferred that the quadrature axis current reference value and the excitation current reference value satisfy: ； In the formula, is the excitation current reference value, is the quadrature axis current reference value, It represents the theoretical ratio of stator resistance to field resistance, and the direct-axis current reference value is set to 0.

2. The motor according to claim 1, characterized in that: The DC excitation winding and the AC armature winding are both concentrated windings.

3. The motor according to claim 1, characterized in that: The quadrature-axis current reference value It is calculated based on the electromagnetic torque reference value output by the speed loop PI regulator, as follows: ； In the formula, It is the electromagnetic torque given value output by the speed loop proportional integral regulator. is the excitation current sampling value, is the number of pole pairs of the motor, It is the mutual inductance between the AC armature winding and the DC field winding.

4. The motor according to claim 1, characterized in that: The number of stator teeth is 12, and the number of rotor teeth is 10.

5. A method for estimating stator resistance of a motor according to any one of claims 1 to 4, characterized in that: After allocating reference values ​​of direct-axis current, quadrature-axis current and excitation current in the variable reluctance motor based on the principle that the copper loss of the DC excitation winding of the entire motor and the AC armature winding of the entire motor are equal, the stator resistance estimation method includes: Obtain the excitation voltage given value and excitation current sampling value of the variable reluctance motor; The excitation resistance is calculated using the excitation voltage given value and the excitation current sampling value; based on , using the excitation resistance multiplied by a fixed coefficient Get the estimated stator resistance, The theoretical ratio of stator resistance to field resistance is determined by the number of coil turns.

6. The stator resistance estimation method according to claim 5, characterized in that: The excitation resistance is obtained based on the voltage equation of the excitation branch in steady state and embedded in a first-order low-pass filter. The calculation formula is: ； In the formula, Indicates the excitation voltage reference value at the current time k, that is, the excitation voltage given value, Indicates the excitation current sampling value at the current time k, is the estimated value of the excitation resistance at the current time k, represents the estimated value of the excitation resistance at time k-1, represents the bandwidth of the first-order low-pass filter of the excitation resistor, is the sampling period.

7. A motor control method based on the stator resistance estimation method according to claim 6, characterized in that: The estimated stator resistance is input into the observer, and the motor control method includes: Obtain the current sampling value and voltage reference value of the variable reluctance motor on the dq axis in the rotating coordinate system; Input the excitation current sampling value, the current sampling value of the dq axis, and the voltage reference value into the observer to obtain the current estimation value of the dq axis; Calculate the current estimation error of the dq axis, and input the current estimation error into the speed and rotor position estimation module to obtain the speed estimation value and the rotor position angle estimation value, and then feed the obtained speed estimation value, the rotor position angle estimation value, and the stator resistance estimation value back to the observer for speed and position estimation at the next moment; The current estimation error of the dq axis is the difference between the current estimation value and the current sampling value.

8. A control system based on the motor control method according to claim 7, characterized in that: At least: A current distribution module is used to distribute reference values ​​of direct-axis current, quadrature-axis current and excitation current in the variable reluctance motor based on the principle that the copper loss of the DC excitation winding of the entire motor and the AC armature winding of the entire motor are equal; The excitation resistance and stator resistance estimation module is used to first calculate the excitation resistance and then multiply the excitation resistance by a fixed coefficient. Get the estimated stator resistance; The sampling module is used to obtain the current sampling value and voltage reference value of the variable reluctance motor on the dq axis in the rotating coordinate system; An observer, used to estimate the current estimation values ​​of the dq axes; A speed and rotor position estimation module, used to obtain a speed estimation value and a rotor position angle estimation value using the current estimation error of the dq axes; Among them, the speed estimation value, the rotor position angle estimation value, and the stator resistance estimation value are fed back to the observer for speed and position estimation at the next moment; the current estimation error of the dq axis is the difference between the current estimation value and the current sampling value.

9. A computer-readable storage medium, characterized in that: A computer program is stored, which is called by a processor to implement: The reference values ​​of the direct-axis current, quadrature-axis current and excitation current in the variable reluctance motor are allocated on the principle that the copper loss of the DC excitation winding of the entire motor and the AC armature winding of the entire motor are equal, and the motor is the motor with alternating excitation coils and armature coils as claimed in claim 1; First calculate the excitation resistance, then based on , using the excitation resistance multiplied by a fixed coefficient The estimated stator resistance is obtained and fed back to the observer. It represents the theoretical ratio of stator resistance to field resistance; Obtain the current sampling value and voltage reference value of the variable reluctance motor on the dq axis in the rotating coordinate system; Input the excitation current sampling value, the current sampling value of the dq axis, and the voltage reference value into the observer to obtain the current estimation value of the dq axis; Calculate the current estimation error of the dq axis, and input the current estimation error into the speed and rotor position estimation module to obtain the speed estimation value and the rotor position angle estimation value, and then feed the obtained speed estimation value, rotor position angle estimation value, and stator resistance estimation value back to the observer for speed and position estimation at the next moment; wherein the current estimation error of the dq axis is the difference between the current estimation value and the current sampling value.

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