Motor, stator resistance estimation method and control method and system

Abstract

The invention discloses a motor, a stator resistance estimation method, a stator resistance control method and a stator resistance control system, a motor body structure is optimized, direct-current excitation coils and alternating-current armature coils on two adjacent stator teeth are alternately arranged, so that the stator resistance can be estimated by introducing a winding structure which is alternately arranged; heat dissipation conditions of the excitation winding and the armature winding are homogenized; the invention further provides a current distribution strategy, so that copper losses generated by the excitation winding and the armature winding are equal, and the problem of temperature equalization of the armature winding and the excitation winding of the motor is solved. Under the condition that heating and heat dissipation conditions are the same, excitation resistance and stator resistance have a fixed proportional relation, the stator resistance online identification method is provided based on the principle, the technical defect that a traditional identification method is affected by inverter nonlinearity and other parameter errors is overcome, and the identification accuracy is improved. Finally, accurate estimation of the motor rotating speed and the rotor position is realized, and the reliability and the stability of motor control are improved.

Description

Technical Field

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

[0002] The variable reluctance motor is a new type of stator-excited brushless synchronous motor, which 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, small torque fluctuation, etc. It has good application prospects in electric vehicles, mining equipment, aviation power generation or industrial automation. The magnetic field oriented control of the synchronous motor requires precise rotor position. Mechanical position sensors have disadvantages such as low reliability, high cost, electromagnetic interference, etc., and sometimes even impossible to install. In order to reduce the negative impact of position sensors on the control system, it is necessary to develop speed sensorless control technology.

[0003] On the one hand, the back electromotive force of the motor contains the rotor position information. The full-order observer based on the back electromotive force is a classic speed sensorless control technology. It estimates the rotor position and speed information by sampling the motor voltage and current and using the motor mathematical model, and has excellent performance. However, there are still some problems in the application of variable reluctance motors: the armature winding and the excitation winding are both 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 large, which may damage the winding insulation and reduce the life of the motor. Therefore, achieving temperature balance of the armature winding and the excitation winding in this field is a technical problem that needs to be overcome.

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

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

[0006] Therefore, with respect to the body design of the variable flux reluctance motor and its position sensorless control technology, how to achieve temperature balance between the motor armature winding and the excitation winding is the most urgent issue to be solved in the present invention. Summary of the invention

[0007] In order to overcome the technical obstacle of temperature balance of motor armature winding and excitation winding and solve the technical problem, the technical solution of the present invention provides a motor, stator resistance estimation method and control method and system, specifically a variable reluctance motor with alternating excitation coil and armature coil, by optimizing the structure of the motor body, adopting the radial inside and outside alternating arrangement structure of DC excitation coil and AC armature coil, so that the heat dissipation capacity of DC excitation winding and AC armature winding is the same, and by controlling the copper loss of excitation winding and armature winding, the temperature of excitation winding and armature winding is the same, overcoming the problem of uneven temperature distribution of two sets of motor windings in traditional winding structure. On the other hand, based on the optimization of the motor body structure, a new stator resistance estimation method and motor control method are proposed, which overcomes the technical defects of traditional stator resistance identification method affected by inverter nonlinearity and other parameter errors, does not require motor parameters such as direct axis inductance, quadrature axis, inductance, mutual inductance, does not depend on speed and rotor position, and has higher identification accuracy and less calculation.

[0008] To this end, the present invention provides the following technical solutions:

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

[0010] 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;

[0011] The reference values ​​of the direct-axis current, quadrature-axis current and excitation current in the variable reluctance motor are distributed 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.

[0012] In the traditional winding form without alternation, all DC excitation coils are on the outside and all 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 capacity of the two coils is different. According to the equivalent thermal circuit principle of the motor, the technical solution of the present invention arranges the DC excitation coil and the AC armature coil alternately, and the thermal resistance and thermal capacity of the DC excitation coil and the AC armature coil are equal. In order to achieve the same heat dissipation capacity of the excitation winding and the armature winding of the entire motor, the technical solution of the present invention alternately arranges the excitation coil and the armature coil so that the total length of the heat transfer path is equal and the heat dissipation capacity is the same. Because the technical solution of the present invention actively controls the copper loss of the DC excitation winding and the AC armature winding to be equal, their heating power is equal. When the heating power and the heat dissipation capacity are equal, the temperature of the two sets of windings is equal, and there is a fixed ratio between their resistance values.

[0013] The technical solution of the present invention allocates the current reference value according to this method, that is, the copper loss of the DC excitation winding is equal to the copper loss of the AC armature winding, and there exists:

[0014] ;

[0015] ;

[0016] 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.

[0017] make ,get

[0018] ;

[0019] make , we can get:

[0020] ;

[0021] Based on the above reasoning, the quadrature axis current reference value and the excitation current reference value are defined to satisfy:

[0022] ;

[0023] 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 excitation resistance; the direct axis current reference value is set to 0.

[0024] The salient pole 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, the DC excitation winding and the AC armature winding are both concentrated windings.

[0026] Preferably, 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:

[0027] ;

[0028] 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.

[0029] Preferably, the number of stator teeth is 12, and the number of rotor teeth is 10.

[0030] In a second aspect, the present invention provides a method for estimating the stator resistance of the above motor, after allocating reference values ​​of the direct-axis current, quadrature-axis current and excitation current in the variable reluctance motor 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 method comprises:

[0031] Obtain the excitation voltage given value and excitation current sampling value of the variable reluctance motor;

[0032] The excitation resistance is calculated using the excitation voltage given value and the excitation current sampling value;

[0033] The excitation resistance is 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.

[0034] Preferably, 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, and the calculation formula is:

[0035] ;

[0036] 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.

[0037] In a third aspect, the present invention provides a motor control method based on the above-mentioned stator resistance estimation method, wherein the estimated stator resistance is input into an observer, and the method comprises:

[0038] Obtain the current sampling value and voltage reference value of the variable reluctance motor on the dq axis in the rotating coordinate system;

[0039] Inputting the excitation current sampling value, the current sampling value of the dq axis, and the voltage reference value into an observer to obtain the current estimation value of the dq axis;

[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 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;

[0041] The current estimation error of the dq axis is the difference between the current estimation value and the current sampling value.

[0042] In a fourth aspect, the present invention provides a control system based on the above motor control method, comprising at least:

[0043] 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;

[0044] 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;

[0045] 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;

[0046] An observer, used to estimate the current estimation values ​​of the dq axes;

[0047] 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;

[0048] 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.

[0049] In a fifth aspect, the present invention provides a computer-readable storage medium storing a computer program, wherein the computer program is called by a processor to implement:

[0050] 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 DC excitation winding of the entire motor and the AC armature winding of the entire motor are equal;

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

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

[0053] 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;

[0054] 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 respectively, 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.

[0055] Beneficial Effects

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

[0057] 1. The variable reluctance motor provided by the technical solution of the present invention introduces an alternately arranged winding structure to even out the heat dissipation conditions of the excitation winding and the armature winding, so that the heat dissipation capacity of the armature winding and the excitation winding is the same, avoiding the problem of uneven heat dissipation, and combining with the equal copper loss current distribution module to ensure the temperature balance of the excitation winding and the armature winding, overcoming the problem of uneven temperature distribution of the two sets of motor windings in the traditional winding structure, avoiding the problems of insulation burning and short circuit of the coil caused by excessive temperature of a certain winding, and improving the life of the motor.

[0058] 2. The motor and control method of the present invention can accurately identify the excitation resistance and stator resistance, thereby improving the position estimation accuracy of the observer and solving the problem of excessive current caused by position error. The motor can work stably in the high efficiency area, thereby improving the efficiency of the system and achieving important improvements in high efficiency and energy saving.

[0059] 3. The present invention can accurately estimate the excitation resistance and stator resistance. The proposed method overcomes the technical defects of the traditional stator resistance identification method that is affected by the nonlinearity of the inverter and other parameter errors. It does not require motor parameters such as direct-axis inductance, quadrature-axis inductance, mutual inductance, etc., does not depend on the speed and rotor position, and has higher identification accuracy and less calculation. Among them, the stator resistance proposed in the technical solution of the present invention is essentially based on the excitation voltage reference value divided by the excitation current sampling value, multiplied by the fixed coefficient of stator resistance and excitation resistance. Got it, ,It is obvious that 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 capacity is improved, the accurate estimation of the motor speed and rotor position is achieved, and the reliability and stability of the motor control method are ensured. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0063] Figure 3 Schematic diagram of the control principle of the method according to an embodiment of the present invention.

[0064] Figure 4 This is a schematic diagram of a current distribution module according to an embodiment of the present invention.

[0065] Figure 5The figure is a schematic diagram of the internal structure of the excitation resistance and stator resistance estimation module of the method according to the embodiment of the present invention.

[0066] Figure 6 FIG. 4 is a schematic diagram of the interior of an observer according to an embodiment of the present invention.

[0067] Figure 7 This is a schematic diagram of a speed and rotor position estimation module proposed in an embodiment of the present invention.

[0068] Among them: 1, DC excitation coil; 2, AC armature coil; 3, stator; 4, rotor. DETAILED DESCRIPTION

[0069] The technical solution of the present invention provides a motor, a stator resistance estimation method, a control method and a system, specifically, a variable reluctance motor with alternating excitation coils and armature coils is proposed, by optimizing the motor body structure, adopting a new winding structure in which DC excitation coils and AC armature coils are alternately arranged radially inside and outside, the heat dissipation conditions of the excitation winding and the armature winding are equalized, and the problem of uneven heat dissipation is avoided; a current distribution strategy is proposed to make the copper loss generated by the excitation winding and the armature winding equal. In addition, under the same heating and heat dissipation conditions, the technical solution of the present invention has a fixed proportional relationship between the excitation resistance and the stator resistance. Based on this principle, a stator resistance online identification method is proposed. The excitation resistance and stator resistance obtained by online identification can realize the temperature estimation of the excitation winding and the armature winding, and the variable reluctance motor is thermally protected to prevent the motor from burning due to overheating. The present invention will be further described in conjunction with the embodiments below.

[0070] Different from Figure 2 The conventional motor body structure shown in FIG. 1 is a motor with alternating excitation coils and armature coils provided by the technical solution of the present invention. Figure 1 The variable reluctance motor shown. It at least includes a DC excitation coil 1, an AC armature coil 2, a stator 3, and a rotor 4. The stator 3 and the rotor 4 are both salient pole structures, both of which are made of laminated silicon steel sheets and are nested together in a concentric and coaxial manner. The stator 3 is provided with stator teeth facing the rotor 4, and each of the stator teeth 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 coil 1 and the AC armature coil 2 on two adjacent stator teeth are arranged alternately. For example, on the first tooth, the DC excitation coil 1 is radially close to the outer side of the stator 3, and the AC armature coil is close to the inner side of the stator 3. On the second tooth, the DC excitation coil 1 is radially close to the inner side of the stator 3, and the AC armature coil is close to the outer side of the stator 3. The variable reluctance motor provided in this embodiment 1 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 possible embodiments, there is no restriction on this.

[0071] The present invention optimizes the motor body structure so that the heat dissipation capacity of the DC excitation winding and the AC armature winding is the same, which effectively improves the problem of winding insulation burning caused by uneven temperature during motor operation, and prolongs the service life of the motor. In order to achieve the same heating capacity of the two sets of windings, the present invention distributes the direct-axis current, the quadrature-axis current and the excitation current based on the principle of equal copper loss of the armature winding and the excitation winding according to the electromagnetic torque reference value output by the speed loop PI regulator. Thereby, the heat dissipation capacity and heat generation capacity of the two sets of windings are truly the same, and the temperature of the excitation resistor and the stator resistor is consistent.

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

[0073] like Figure 4 As shown, through Figure 4 The current distribution module realizes the distribution of direct-axis current, quadrature-axis current and excitation current. Based on the principle that the copper loss of the excitation winding and the armature winding is equal, the excitation current reference value is inferred. and quadrature axis current reference The following conditions must be met: The salient pole ratio of the variable reluctance motor is basically 0, and the reluctance torque does not need to be used. Therefore, the reference value of the direct-axis current adopts a simple =0 control strategy.

[0074] Among them, 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:

[0075] ;

[0076] In the formula, It is the electromagnetic torque given value output by the speed loop proportional integral regulator. is the given 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 field winding, is the sampled excitation current, is the given value (reference value) of the excitation current, is the given value (reference value) of the direct-axis current.

[0077] In some embodiments, the technical solution of the present invention further provides a stator resistance estimation method based on the above motor. After the direct-axis current, quadrature-axis current and excitation current in the variable reluctance motor are equally distributed by the copper loss of the DC excitation winding and the AC armature winding on the variable reluctance motor, the stator resistance estimation method includes:

[0078] S1: Get the motor's excitation voltage given value and excitation current sampling value;

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

[0080] S3: 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.

[0081] like Figure 5 As shown, the excitation resistance of this embodiment is calculated by the steady-state voltage equation of the excitation branch, and a first-order low-pass filter is embedded to make the identification result smoother. Since the stator resistance and the excitation motor of the present invention have a fixed proportional relationship, the stator resistance is calculated by multiplying the excitation resistance by a fixed coefficient You can get it.

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

[0083] In order to make the estimated excitation resistance smoother, a first-order low-pass filter is embedded, and its expression is:

[0084] ;

[0085] In the formula, represents the excitation voltage reference value at the current time k, represents 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 the last sampling period k-1, The bandwidth of the first-order low-pass filter of the excitation resistor is generally selected , is the sampling period. represents an integrator, The theoretical ratio of stator resistance to excitation resistance is determined by the number of coil turns and the number of coils. In the present invention, it is 1 / 3. is the estimated stator resistance.

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

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

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

[0089] S22: inputting the excitation current sampling value and the current sampling value of the dq axis, the voltage reference value, and the speed estimation value into an observer to obtain the current estimation value of the dq axis;

[0090] S23: 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 respectively, and then feed back the obtained speed estimation value, rotor position angle estimation value and the aforementioned stator resistance estimation value 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 corresponding current estimation value and the current sampling value.

[0091] It should be understood that Figure 3 As shown, based on the principle of vector control, the phase current i in the variable reluctance motor is measured. a ,i b After coordinate transformation, the direct axis current and quadrature axis current are obtained. These two currents are sent to the dq current loop as feedback values. Together with the given value, they are sent to the proportional integral module (PI module) of the current loop. The PI regulation output is used to obtain the dq axis voltage u d ,u q Then it is sent to the SVPWM space vector pulse width modulation module to control the on and off of the IGBT in the three-phase inverter to achieve the control of the armature circuit. In the excitation circuit, the excitation current is sampled and then sent to the excitation current loop as a feedback value, which is compared with the excitation current given value. Together, they are sent to the proportional integral module (PI module) of the excitation current loop, and the PI regulation output is used to obtain the excitation voltage reference value. Then it is sent to the PWM pulse width modulation module to control the on and off of the IGBT in the H-bridge inverter to achieve the control of the excitation circuit. It should be noted that this part of the control process is the existing technology in this field, so it will not be described in detail.

[0092] In order to more clearly demonstrate the observer and the estimation scheme of the speed and the rotor position, an example will be given below, but the technical solution of the present invention is not limited to the following mathematical model.

[0093] About the observer:

[0094] like Figure 6 As shown, the direct axis flux is first calculated by estimating the flux equations of the direct axis and the quadrature axis. and cross-axis flux , then calculate the direct axis and the estimated current of the quadrature axis .

[0095] ;

[0096] ;

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

[0098] in:

[0099] ;

[0100] in:

[0101] , , They are all intermediate variables, namely:

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

[0103] Estimated speed and rotor position estimation module:

[0104] like Figure 7 As shown, the estimated quadrature axis current Subtract the quadrature axis current in the rotating coordinate system , and get the current error , an estimated speed is obtained through a PI regulator, and the estimated speed is integrated to obtain the estimated angle.

[0105] ;

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

[0107] ,in, For speed adaptive bandwidth, generally selected , is the intermediate variable, , are the estimated values ​​of d-axis and q-axis inductances, is the estimated mutual inductance, is the d-axis current sampling value, is the excitation current sampling value.

[0108] In some embodiments, the present invention provides a control system based on the above motor control method, which 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 excitation current in the variable reluctance motor by making the copper loss of the DC excitation coil and the AC armature coil equal; the excitation resistance and stator resistance estimation module is connected to the observer to calculate the excitation resistance first, and then multiply the excitation resistance by a fixed coefficient. The estimated stator resistance is obtained, and then the estimated stator resistance is transmitted to the observer; the sampling module is connected to the observer, and is used to obtain the current sampling value and voltage reference value of the motor on the rotating coordinate system of the dq axis, and transmit them to the observer; the observer is used to estimate the current estimation value of the dq axis, and transmit it to the speed and rotor position estimation module; the speed and rotor position estimation module is used to obtain the speed estimation value and the rotor position angle estimation value by using the current estimation error of the dq axis, and transmit them to the observer and the speed loop, the speed loop uses the speed error to calculate and determine the electromagnetic torque given value, and transmits it to the current distribution module, which is used to distribute the direct axis current, quadrature axis current and excitation current in the variable reluctance motor.

[0110] 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.

[0111] It should be noted that the implementation process of each module is referred to the content of the above method, which will not be repeated here. It should be understood that the division of the above functional modules is only a division of logical functions, and there may be other division methods in actual implementation, such as 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 units can be implemented in the form of hardware or in the form of software functional units.

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

[0113] The direct-axis current, quadrature-axis current and excitation current in the variable reluctance motor are distributed by making the copper loss of the DC excitation coil and the AC armature coil equal;

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

[0115] Obtain the current sampling value and voltage reference value of the variable reluctance motor on the dq axis in the rotating coordinate system;

[0116] 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;

[0117] The current estimation error of the dq axis is calculated, and the current estimation error is input into the speed and rotor position estimation module to obtain the speed estimation value and the rotor position angle estimation value respectively. The obtained speed estimation value, rotor position angle estimation value and stator resistance estimation value are then fed 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.

[0118] For the specific implementation process of each step, please refer to the description of the above 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 aforementioned embodiments, such as a hard disk or memory of a controller. The readable storage medium may also be an external storage device of the controller, such as a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), etc. equipped on the controller. Furthermore, the readable storage medium may also include both an internal storage unit of the controller and an 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 data that has been output or is to be output.

[0120] Based on this understanding, the technical solution of the present invention is essentially 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, which is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned readable storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0121] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-readable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes. The present application is a device for realizing the function specified in one flow or multiple flows of the flow chart and / or one or multiple blocks of the block diagram with reference to the instructions executed by the processor according to the method, device (system) and computer program product of the embodiment of the present application. These computer program instructions can also be stored in a computer-readable memory that can guide a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory produce a product including an instruction device, which realizes the function specified in one flow or multiple flows of the flow chart and / or one or multiple blocks of the block diagram. These computer program instructions may also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, whereby the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0122] It should be emphasized that the examples described in the present invention are illustrative rather than restrictive, and therefore the present invention is not limited to the examples described in the specific embodiments. Any other embodiments derived by those skilled in the art based on the technical solution of the present invention that do not depart from the purpose and scope of the present invention, whether modified or replaced, also fall within the scope of protection 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 distributed 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.

2. The motor according to claim 1, characterized in that: The direct-axis current reference value is set to 0, and 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 excitation resistance.

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

4. The motor according to claim 2, 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.

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

6. A method for estimating stator resistance of a motor according to any one of claims 1 to 5, 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; The excitation resistance is 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.

7. The stator resistance estimation method according to claim 6, 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, represents 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.

8. A motor control method based on the stator resistance estimation method according to claim 7, 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.

9. A control system based on the motor control method according to claim 8, 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.

10. 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 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; First calculate the excitation resistance, and then multiply the excitation resistance 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.

Images