ARM-based dual-channel rotary transformer feedback servo driver, motor driving method and system

Abstract

The invention discloses an ARM-based dual-channel resolver feedback servo driver and a motor driving method and system, and the servo driver comprises a resolver resolving circuit which is used for collecting an analog signal outputted by a motor, converting the analog signal into a digital angle signal, and transmitting the digital angle signal to an MCU; the MCU is used for resolving a position angle value according to the digital angle signal based on an ARM control architecture; and the power output and current sampling module is used for calculating a three-phase voltage according to the position angle value, outputting the three-phase voltage to the motor and carrying out real-time current sampling at the same time. According to the invention, the position measurement precision is improved by using a double-channel rotary transformer feedback and double-speed decoding mode, the steady-state precision and the response time are improved compared with those of a traditional PI controller, and a control scheme of an ARM architecture is adopted, so that the cost of the controller is lower, the cost is lower, and the power density of the controller is further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of embedded servo control, in particular to a time-domain flexible vibration sensor speech enhancement algorithm combining a dual-path Transformer and an equalization-generation component prediction. Background Art

[0002] With the rapid development of science and technology, especially the rapid development of motor manufacturing and control technology, as well as the development of large-scale integrated circuits, semiconductor power devices and microprocessors, permanent magnet synchronous motors equipped with dual-channel resolvers and their servo drivers have been widely used in military, industrial automation production and medical fields. Especially in the field of aerospace, there are high requirements for the volume, reliability and steady-state accuracy of the driver. Its simple structure and high power density make it the first choice for servo systems. In the control circuit, traditional drivers use TI's DSP2000 series new products as MCUs, which are costly and relatively complex to implement in software. Especially in the localization of military industry, there are few localized products and it is difficult to replace them with localized ones. In addition, the measurement accuracy of traditional permanent magnet synchronous motors using single-channel resolver feedback is relatively low, which affects the control effect of the servo driver. Summary of the invention

[0003] The purpose of the present invention is to provide an ARM-based dual-channel resolver feedback servo driver in view of the problems existing in the above-mentioned prior art, wherein sampling, communication and control algorithms are implemented by ARM, including dual-channel resolver solution circuit design and coarse channel and fine channel angle combination method, as well as ARM-implemented system master control architecture design and current loop control method. The position feedback accuracy is improved by dual-channel resolver, so that the d-axis and q-axis current solution accuracy in the permanent magnet synchronous motor current loop control is higher, the current loop steady-state control error is smaller, and the response time is faster.

[0004] The technical solution to achieve the purpose of the present invention is: on the one hand, a dual-channel resolver feedback servo driver based on ARM is provided, and the driver comprises:

[0005] The resolver circuit is used to collect the analog signal output by the motor and convert the analog signal into a digital angle signal and transmit it to the MCU;

[0006] MCU, used for calculating the position angle value according to the digital angle signal based on the ARM control architecture;

[0007] The power output and current sampling module is used to calculate and output the three-phase voltage to the driver of the motor according to the position angle value, drive and adjust the operation of the motor, and perform real-time current sampling.

[0008] Furthermore, the resolver solving circuit adopts a dual-channel resolver, including a coarse channel and a fine channel, and outputs two digital angle signals to the MCU.

[0009] Furthermore, the coarse and fine dual channels both use AD2S1210 chips.

[0010] Furthermore, the ARM control architecture implements closed-loop control based on an improved predictive control algorithm with dual-channel resolver feedback, and the control rate equation of the algorithm is:

[0011]

[0012]

[0013] In the formula, are the estimated values ​​of the d-axis and q-axis currents obtained by the observer at time k+1, are respectively the estimated values ​​of the voltage changes of the d-axis and q-axis caused by the motor parameter deviation at time k, is the estimated value of the voltage change of the d-axis and q-axis caused by the motor parameter deviation at time k+1, F ds (k), F qs (k) are the d-axis and q-axis voltage switching control rates at time k, respectively. d , k q are the sliding mode parameters of the d-axis and q-axis respectively, R is the stator resistance, L is the d-axis and q-axis synchronous inductance, T is the sampling period, i d (k), i q (k) are the actual currents of d-axis and q-axis at time k, u d (k),u q (k) are the actual voltages of the d-axis and q-axis at time k, ω e (k) is the electromagnetic speed at time k, ψ f is the rotor flux.

[0014] Furthermore, the calculated position angle value is specifically:

[0015] angle=((θ c >>(mn))<<m)|θ j (3)

[0016] In the formula, angle is the calculated position angle value, θ c ,θ j They are respectively the m-digit digital angle of the coarse channel and the n-digit digital angle of the fine channel.

[0017] Furthermore, the MCU adopts GD32F4XX series ARM.

[0018] On the other hand, a motor driving method is provided, which is applied to the above servo drive, and the method comprises:

[0019] The analog signal output by the motor is collected based on the resolver circuit, and the analog signal is converted into a digital angle signal and transmitted to the MCU;

[0020] The MCU is based on the ARM control architecture and calculates the position angle value according to the digital angle signal;

[0021] The output three-phase voltage is calculated according to the position angle value to the driver of the motor, so as to drive and adjust the operation of the motor.

[0022] Furthermore, after the step of calculating and outputting a three-phase voltage to the motor according to the position angle value, and driving and regulating the operation of the motor, the method further includes:

[0023] Current sampling is performed in real time.

[0024] Furthermore, the method further comprises:

[0025] The motor status is determined based on the sampled current. If the motor status is within the preset alarm condition, the motor is stopped.

[0026] On the other hand, a motor drive system is provided, which includes a motor, an external controller and a servo driver, wherein the servo driver is connected to the motor and the external controller respectively, and is used to control the operation of the motor under the control of the external controller.

[0027] Compared with the prior art, the present invention has the following significant advantages:

[0028] (1) The position feedback accuracy is improved by using a dual-channel resolver. The position angle fed back to the driver can improve the control accuracy of the permanent magnet synchronous motor (PMSM). This makes the d-axis and q-axis current calculation accuracy higher in the current loop control of the permanent magnet synchronous motor, the current loop steady-state control error smaller (i.e., the steady-state accuracy is improved), and the response time faster.

[0029] (2) It is proposed that the dual-channel resolver feedback of the MCU using ARM as the controller can effectively improve the system control accuracy, simplify the hardware design, reduce the design cost, and increase the power density of the controller.

[0030] The present invention is further described in detail below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 FIG. 1 is a principle block diagram of a dual-channel resolver feedback driver according to an embodiment of the present invention.

[0032] Figure 2 FIG. 1 is a principle block diagram of an embodiment of the present invention in which the ARM is used as the MCU.

[0033] Figure 3 1 is a control structure schematic diagram of an improved predictive control algorithm based on dual-channel resolver feedback of the present invention in one embodiment.

[0034] Figure 4 is a schematic diagram of a current tracking curve in an embodiment, wherein Figure 4 (a) and (b) are respectively the current tracking curve under the dual-channel feedback of the present invention and the current tracking curve of the traditional PI controller. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0036] It should be noted that if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0037] It should be noted that the following embodiments are described using a permanent magnet synchronous motor.

[0038] In one embodiment, in combination Figure 1 , provides an ARM-based dual-channel resolver feedback servo driver, the driver comprising:

[0039] The resolver circuit is used to collect the analog signal output by the motor and convert the analog signal into a digital angle signal and transmit it to the MCU;

[0040] MCU, used for calculating the position angle value according to the digital angle signal based on the ARM control architecture;

[0041] The power output and current sampling module is used to calculate the three-phase voltage according to the position angle value and output it to the motor, and perform real-time current sampling at the same time.

[0042] Here, the most important reason why ARM is widely used in embedded systems is that it supports Thumb (16-bit) / ARM (32-bit) dual instruction sets, and is well compatible with 8-bit / 16-bit devices; it uses a large number of registers, and the instruction execution speed is faster; most data operations are completed in registers; the addressing method is flexible and simple, the execution efficiency is high, and the instruction length is fixed. Load_store structure: In RISC, all calculations are required to be completed in registers. The communication between registers and memory is completed by separate instructions. In CSIC, the CPU can directly operate on the memory.

[0043] Furthermore, in one of the embodiments, the resolver solving circuit adopts a dual-channel resolver, including a coarse channel and a fine channel, and outputs two digital angle signals to the MCU.

[0044] Here, in some embodiments, for a single-channel resolver, an AD2S1210 chip, i.e., a peripheral circuit, is used, such as Figure 2 The coarse and fine dual channels use the same circuit to obtain two 16-bit digital angles of the dual-channel resolver, and the position angle value is specifically calculated as:

[0045] angle=((θ c >>(mn))<<m)|θ j (4)

[0046] In the formula, angle is the calculated position angle value, θ c ,θ j They are respectively the coarse channel m=16-bit digital angle and the fine channel n=16-bit digital angle.

[0047] By adopting the solution of this embodiment, the angle measurement accuracy is further improved by measuring the angle with a coarse and fine dual-speed resolver and decoding, so that the measured values ​​of the d-axis and q-axis currents are further improved, and the vector calculation accuracy in the Clarkpark transformation is higher.

[0048] Furthermore, in one embodiment, the ARM control architecture implements closed-loop control based on an improved predictive control algorithm with dual-channel resolver feedback, and the control rate equation of the algorithm is:

[0049]

[0050]

[0051] In the formula, are the estimated values ​​of the d-axis and q-axis currents obtained by the observer at time k+1, are respectively the estimated values ​​of the voltage changes of the d-axis and q-axis caused by the motor parameter deviation at time k, is the estimated value of the voltage change of the d-axis and q-axis caused by the motor parameter deviation at time k+1, F ds (k), F qs (k) are the d-axis and q-axis voltage switching control rates at time k, respectively. d , k q are the sliding mode parameters of the d-axis and q-axis respectively, R is the stator resistance, L is the d-axis and q-axis synchronous inductance, T is the sampling period, i d (k), i q (k) are the actual currents of d-axis and q-axis at time k, u d (k),u q (k) are the actual voltages of the d-axis and q-axis at time k, ω e (k) is the electromagnetic speed at time k, ψ f is the rotor flux.

[0052] The specific analysis here is as follows:

[0053] (1) Establishing the control object model

[0054] The equation of permanent magnet synchronous motor in the rotating coordinate system is:

[0055]

[0056] Among them, i d 、i q are the actual currents of the d-axis and q-axis respectively, R is the stator resistance; L is the synchronous inductance of the d-axis and q-axis; ω e is the electromagnetic speed; ψ f is the rotor flux;

[0057] The electromagnetic torque equation is:

[0058]

[0059] Among them, T e is the electromagnetic torque, p n is the number of motor pole pairs.

[0060] (2) Control algorithm design

[0061] will i q 、i d Discretization gives formula (9):

[0062]

[0063] In the formula, i d (k), i q (k) are the actual currents of the d-axis and q-axis at time k, i d (k+1), iq (k+1) are the actual currents of d-axis and q-axis at time k+1;

[0064] Substituting equation (9) into equation (7), we get the discrete current prediction model:

[0065]

[0066] in,

[0067]

[0068] i(k+1)=[i d (k)i q (k)]

[0069]

[0070] In the formula, ω e (k) is the electromagnetic speed at time k;

[0071] The model predictive control rate is obtained from the discretized state space equation:

[0072]

[0073] In the formula, i * (k) is the given current, i(k) is the actual current;

[0074] The calculated current is modulated by SVPWM;

[0075] The sliding mode variable structure is used to design the observer, and the parameter disturbance is fed back to the control voltage as the compensation. When there is a deviation in the motor parameters in the controller, according to formula (7):

[0076]

[0077]

[0078] In the formula, f d 、f q are the voltage disturbances of the d-axis and q-axis when the parameters are disturbed, F d 、F q They are the change rates of the voltage disturbances on the d-axis and q-axis when the parameters are disturbed.

[0079] In order to obtain the estimated values ​​of current and parameters after disturbance, a sliding mode disturbance observer is used and a sliding mode control rate is introduced.

[0080] The sliding mode control rate consists of the equivalent control rate f and the switching control rate F.

[0081]

[0082]

[0083] In the formula, are the estimated values ​​of d-axis and q-axis currents, respectively. are the estimated values ​​of the d-axis and q-axis voltage changes caused by the motor parameter deviation, respectively. ds 、F qs are the d-axis and q-axis voltage switching control rates, k d , k q are the sliding mode parameters of the d-axis and q-axis respectively.

[0084] Subtract (16) from (14) and (17) from (15) to obtain:

[0085]

[0086]

[0087] In the formula, are the d-axis and q-axis current estimation deviations, respectively; are the d-axis and q-axis voltage estimation errors respectively.

[0088] Select the linear sliding surface:

[0089]

[0090] The improved exponential approximation rate is:

[0091]

[0092] Among them, ε, q is the approach gain. When the above approach rate is used, when the error is large, the approach is large and Proportional to the speed of response, this approach rate is used to improve the response speed and weaken the jitter.

[0093] Due to e 2 、e 4 is included in the control function, so it can be approximated as:

[0094]

[0095] In the formula, q d ,q q are the d-axis component and q-axis component of q respectively;

[0096] Discretize the observation equation to get:

[0097]

[0098]

[0099] In the formula, are the estimated values ​​obtained by the observer, replacing the current measurement values ​​in the model predictive control, are the estimated d-axis and q-axis voltage compensation values ​​respectively. Figure 3 shown.

[0100] Preferably, in some embodiments, the MCU adopts the domestic GD32F4XX series ARM. Its rich peripheral interfaces meet all the functions of servo control, use the internal 12-bit AD as the phase current of the sampling servo motor, and use the serial communication module for the debugging interface between the controller and the host computer. It also contains an orthogonal decoding module for decoding the incremental encoder, but the present invention uses a resolver with a 1210 decoding chip as position feedback, and uses ARM for digital shift processing for angle combination. Cortex TM -M4 processor is based on ARMv7 architecture and supports a powerful and scalable instruction set, including general data processing I / O control tasks, enhanced data processing bit field operations, DSP (digital signal processing) and floating point operation instructions. Its floating point operation capability meets the large number of floating point operations of SVPWM in servo control algorithm. ARM has complementary pwm output function as the front-end input control logic signal of the drive bridge. The principle is as follows Figure 2 shown.

[0101] In one embodiment, a motor driving method is provided, the method being applied to the servo drive, the method comprising:

[0102] The analog signal output by the motor is collected based on the resolver circuit, and the analog signal is converted into a digital angle signal and transmitted to the MCU;

[0103] The MCU is based on the ARM control architecture and calculates the position angle value according to the digital angle signal;

[0104] The output three-phase voltage is calculated according to the position angle value to the driver of the motor, so as to drive and adjust the operation of the motor.

[0105] Furthermore, in one of the embodiments, after the step of calculating and outputting a three-phase voltage to a driver of the motor according to the position angle value, and driving and regulating the operation of the motor, the method further includes:

[0106] Current sampling is performed in real time.

[0107] Furthermore, in one embodiment, the method further comprises:

[0108] The motor status is determined based on the sampled current. If the motor status is within the preset alarm condition, the motor is stopped.

[0109] Here, for the specific limitations of the servo driver, please refer to the limitations of the ARM-based dual-channel resolver feedback servo driver mentioned above, which will not be repeated here.

[0110] In one embodiment, a motor drive system is provided, which includes a motor, an external controller and a servo driver as described above, wherein the servo driver is respectively connected to the motor and the external controller, and the servo driver is used to control the operation of the motor under the control of the external controller.

[0111] Here, for the specific limitations of the servo driver, please refer to the limitations of the ARM-based dual-channel resolver feedback servo driver mentioned above, which will not be repeated here.

[0112] As a specific example, in one of the embodiments, the present invention is further verified and explained.

[0113] Using self-developed drivers as hardware carriers, the motor selection specifications are shown in Table 1 below:

[0114] Table 1 Motor parameters

[0115]

[0116] The current response curves of the traditional PI controller and the improved predictive control algorithm based on dual-channel resolver feedback proposed in the present invention were tested respectively. Through comparative tests, it can be seen that the method of the present invention has improved both steady-state accuracy and response speed. The steady-state current tracking curve was tested, such as Figure 4 As shown, it can be seen that the steady-state error is further reduced.

[0117] In summary, the present invention studies the steady-state error of model predictive control and proposes an observer for estimating the change in control quantity caused by the motor parameter transformation, and through engineering experiments, it is verified that the accuracy and response speed are improved compared with the traditional PI control. At the same time, the present invention improves the position measurement accuracy by using dual-channel rotary transformer feedback plus dual-speed decoding. After testing, the steady-state accuracy and response time are improved compared with the traditional PI controller. In addition, the control scheme using the ARM architecture makes the controller cost lower, the price increase is smaller, and the power density of the controller is further improved.

[0118] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A dual-channel resolver feedback servo driver based on ARM, characterized in that: The servo drive comprises: The resolver circuit is used to collect the analog signal output by the motor and convert the analog signal into a digital angle signal and transmit it to the MCU; MCU, used for calculating the position angle value according to the digital angle signal based on the ARM control architecture; The power output and current sampling module is used to calculate the three-phase voltage according to the position angle value and output it to the motor, and perform real-time current sampling at the same time.

2. The ARM-based dual-channel resolver feedback servo driver according to claim 1, characterized in that: The resolver solving circuit adopts a dual-channel resolver, including a coarse channel and a fine channel, and outputs two digital angle signals to the MCU.

3. The ARM-based dual-channel resolver feedback servo driver according to claim 2, characterized in that: The coarse and fine dual channels both use the AD2S1210 chip.

4. The ARM-based dual-channel resolver feedback servo driver according to claim 2, characterized in that: The ARM control architecture implements closed-loop control based on an improved predictive control algorithm based on dual-channel resolver feedback. The control rate equation of the algorithm is: In the formula, are the estimated values ​​of the d-axis and q-axis currents obtained by the observer at time k+1, are respectively the estimated values ​​of the voltage changes of the d-axis and q-axis caused by the motor parameter deviation at time k, is the estimated value of the voltage change of the d-axis and q-axis caused by the motor parameter deviation at time k+1, F ds (k), F qs (k) are the d-axis and q-axis voltage switching control rates at time k, respectively. d , k q are the sliding mode parameters of the d-axis and q-axis respectively, R is the stator resistance, L is the d-axis and q-axis synchronous inductance, T is the sampling period, i d (k), i q (k) are the actual currents of the d-axis and q-axis at time k, u d (k) and u q (k) are the actual voltages of the d-axis and q-axis at time k, ω e (k) is the electromagnetic speed at time k, ψ f is the rotor flux.

5. The ARM-based dual-channel resolver feedback servo driver according to claim 1, characterized in that: The calculated position angle value is specifically: angle=((θ c >>(mn))<<m)|θ j In the formula, angle is the calculated position angle value, θ c ,θ j They are respectively the m-digit digital angle of the coarse channel and the n-digit digital angle of the fine channel.

6. The ARM-based dual-channel resolver feedback servo driver according to claim 1, characterized in that: The MCU adopts GD32F4XX series ARM.

7. A motor driving method, characterized in that: The method is applied to the servo drive according to any one of claims 1 to 6, and the method comprises: The analog signal output by the motor is collected based on the resolver circuit, and the analog signal is converted into a digital angle signal and transmitted to the MCU; The MCU is based on the ARM control architecture and calculates the position angle value according to the digital angle signal; The three-phase voltage is calculated and output to the servo driver according to the position angle value to drive and adjust the operation of the motor.

8. The motor driving method according to claim 7, characterized in that: After the step of calculating and outputting a three-phase voltage to a driver of the motor according to the position angle value, and driving and regulating the operation of the motor, the method further includes: Current sampling is performed in real time.

9. The motor driving method according to claim 8, characterized in that: The method further comprises: The motor status is determined based on the sampled current. If the motor status is within the preset alarm condition, the motor is stopped.

10. A motor drive system, characterized in that: The motor drive system includes a motor, an external controller and a servo driver according to any one of claims 1 to 6, wherein the servo driver is connected to the motor and the external controller respectively, and the servo driver is used to control the operation of the motor under the control of the external controller.

Images