[0026] The torque coupling compensation control method based on the segmented motor of the invention is further described in detail below in combination with the attached drawings and embodiments.
[0027] Permanent magnet synchronous segmented motor will jointly drive an inertial load (i.e. large aperture telescope) to rotate. Permanent magnet synchronous segmented motor includes n-segment segmented motor, n is an integer greater than 2, and the stator of n-segment segmented motor is arranged in sequence along a circle, that is, the n-segment segmented motor is surrounded into a circular structure, which is equivalent to an annular integral stator. They have the same permanent magnet rotor, and the rotor drives the inertial load to move.
[0028] The existing closed-loop structure of segmented motor motion control system is as follows: Figure 1 As shown in, the whole inertial motion system (inertial motion system includes permanent magnet synchronous segmented motor and large aperture telescope) will complete the motion control of the mechanical part of the inertial motion system by a speed loop and a position loop, and the torque output of each segmented motor will be controlled by the segmented motor torque control loop. The control structure of the position loop includes a position controller, and the control structure of the speed loop includes a speed controller. The input signal of the position loop is the position command and position feedback information, and the output is the speed loop command after closed-loop correction; The input signal of the speed loop is the speed loop command and speed feedback information, and the output is the current reference command of the torque loop after closed-loop correction. The torque control of the segmented motor is realized through the segmented motor torque control loop. The segmented motor torque control loop will complete the current closed-loop control and power drive of the multi segment motor system, and finally output the matched total torque to drive the motor system to operate according to the motion command.
[0029] The drive control structure of the segmented motor torque control loop adopts the ring coupling drive structure, that is, the segmented motor torque control loop includes N control drivers, which correspond to n segmented motors one by one. Each segmented motor has a control driver, and each control driver will complete the vector transformation, current closed-loop control, power drive, torque output and other functions of its corresponding segmented motor, This series of processes can be collectively referred to as motor torque control. The control model of the above control driver includes current loop controller, inverter equivalent model and motor electrodynamics equivalent model. The current loop controller is used to control the current closed-loop control of the segmented motor, the inverter equivalent model is used to drive the power of the segmented motor, and the motor electrodynamics equivalent model is used to control the torque output of the segmented motor. Through the design of control algorithm, the control driver can complete the torque control of permanent magnet synchronous segmented motor.
[0030] The inverter model of the control driver is equivalent to The motor electrodynamic model of the control driver is equivalent to The mechanical model of inertial motion system is equivalent to Where, t w Is equivalent time constant of inverter, s is stator, l sx Is the inductance of the stator of the segment x motor, X is a positive integer, R sx Is the resistance value of segment x motor stator, j is the moment of inertia of inertial motion system, and B is the viscous friction coefficient of inertial motion system. In addition, K tx Is the torque coefficient of segment x motor, K bx Is the back EMF coefficient of segment x motor, θ Is the position information of inertial motion system, ω Is the speed information of inertial motion system, i x Is the current of the segment x motor, θ * Reference position information for inertial motion system, ω * Reference speed information for inertial motion system, Is the current reference command of segmented motor, t ex Is the output torque of segment x motor, t e Is the output torque of permanent magnet synchronous segmented motor, t L Is the load moment of inertial motion system, t d Is the disturbance torque of inertial motion system.
[0031]The current loop controller can use the zero pole assignment method and model predictive control method to form the controller according to the motor electrodynamics model. The output action signal acts on the stator end of the segmented motor through the inverter in the control driver. The current is generated in the electronic winding, and the driving torque is generated under the action of the magnetic field, which acts on the inertial load of the inertial motion system to move.
[0032] For the special structure of segmented motor, if each segmented motor has a set of independent control drivers without information interaction with each other, the closed-loop operation is carried out through the overall speed loop of inertial motion system to output a unified current control command, the current command is transmitted to each independent current controller, and the current controller of each segmented motor carries out independent current closed-loop control, Therefore, once there is a parameter difference, different current controllers will inevitably lead to different current response results, which will make the output torque of each segment motor mismatch, resulting in the decline of tracking accuracy. Therefore, the invention will adopt a ring coupling topology to design the segmented motor torque control ring of the system, and its structural diagram is as follows Figure 2 As shown in, the x-th control driver is called the control driver x, the x-th segment motor is called the segment motor x, and the x-th coupling controller is called the coupling controller X. the coupling compensation method of the segment motor torque control loop based on the permanent magnet synchronous segment motor includes the following steps:
[0033] Step 1: the x-th control driver according to the current reference command of the segmented motor Feedback current I of segment x motor qx The motor control information I of segment x is obtained through operation.
[0034] Step 2: the control information 1 of the segment x motor is input to the segment x motor, and the segment x motor outputs the output torque t ex , unknown disturbing moment t of segment x motor dx And t of segment x motor output ex It acts on the inertial load, that is, the output torque and unknown disturbance torque of all segmented motors act on the inertial load.
[0035] Step 3: compare I qx and The feedback error E is obtained x ，e x For I qx and The difference can be obtained by the x-th control driver and sent to the coupling controller, or calculated by other devices x Then it is sent to the x-th control driver and the x-th coupling controller; The x-th coupling controller compares the current I of the segment x motor qx And the current of a segment motor adjacent to the segment x segment motor (the current I of the segment y segment motor qy , y is a positive integer) to obtain the synchronization error E xy ； Preferably, "a segment of segment motor adjacent to the segment x segment motor" is the segment motor on the left side of the segment x segment motor or the segment motor on the right side of the segment x segment motor; Figure 2 Medium e 12 Indicates the synchronization error obtained by comparing the current of the first segment motor and the current of the second segment motor, e 23 Indicates the synchronization error obtained by comparing the current of the second segment motor with that of the third segment motor, e n1 Indicates that the synchronization error is obtained by comparing the current of the segment n motor and the current of the segment 1 motor.
[0036] Step 4. The x-th coupling controller according to E x And e xy The current correction I is obtained by calculation qcx 。
[0037] Step 5: the x-th control driver i qx And I qcx The motor control information II of segment x is obtained through calculation;
[0038] The second segment x motor control information obtained in step 6 and step 5 is input to the segment x motor corresponding to the X control driver in step 5, and the segment x motor outputs the output torque t ex , unknown disturbing moment t of segment x motor dx And t of segment x motor output ex Acting on an inertial load.
[0039] Step 7: return to step 3 and repeat steps 3 to 7 until the permanent magnet synchronous segmented motor stops working, and the torque coupling compensation control ends.
[0040] The coupling controller is an adaptive coupling controller. The coupling controller includes operational gain, and the coupling controller can be adjusted according to the feedback error E x And synchronization error e xy Adjust operation gain K x To ensure that the coupling compensation effect is enhanced when the synchronization error is large, and the coupling interference is reduced when the synchronization error is small.
[0041] The torque coupling compensation control method based on the segmented motor of the invention can suppress the asynchronous problem of current response caused by the difference of model parameters, control drivers or working conditions of the segmented motor of each segment, reduce the mismatch of motor output torque, and improve the stable operation ability and tracking accuracy of the telescope.
[0042]The segmented motor torque control loop of the invention includes not only n control drivers, but also N coupling controllers, n coupling controllers and N control drivers are set one by one, n coupling controllers and N segmented motors are set one by one, the X control driver is connected with the X segmented motor, and the X coupling controller is connected with the X segmented motor and the X control driver.
[0043] The simulation software is used to verify the method of the invention. The number of segments of the permanent magnet synchronous segmented motor is 4, and the theoretical parameters of each segment of the segmented motor are consistent. The resistance value is 1.4 Ω, the inductance value is 44.33ml, the torque constant is 201nm / A, the switching frequency of the inverter is 10kHz, and the bus voltage is set to 220V. When designing each control driver, the difference and change of motor parameters are unknown. Only the design is carried out according to the theoretical value and the zero pole assignment method is adopted to obtain the control parameters of current loop controller. The open-loop frequency domain characteristic curve of inertial motion system is as follows Figure 3 As shown in, given the step command of ± 1a, the ideal current output response of each segment of segmented motor is as follows: Figure 4 As shown in. At this time, the response is ideal, and the response of each segment motor is smooth and consistent. Further, in the simulation, there are differences or changes in the system model parameters during actual use. Set the resistance value of the first segment motor as 1.4 Ω, the inductance value as 38.33ml, the torque constant as 201nm / A, the resistance value of the second segment motor as 2.4 Ω, the inductance value as 44.33ml, the torque constant as 201nm / A, the resistance value of the third segment motor as 1.0 Ω, the inductance value as 44.33ml, the torque constant as 201nm / A, and the resistance value of the fourth segment motor as 1.4 Ω, The inductance value is 44.33ml and the torque constant is 180nm / A. When using traditional parallel independent controller, such as Figure 5 As shown in, the output current response of each segment motor will be different, which will affect the torque synchronization of the inertial motion system. When the segmented motor torque control loop and the coupling compensation method of the invention are adopted, the output current response of each segmented motor tends to be synchronous, and the effect is as follows Figure 6 As shown in. Further, the disturbances of amplitude 0.2A, frequency 5rad / s, π / 2 phase angle, amplitude 0.1A, frequency 5rad / s, π phase angle, amplitude 0.1A, frequency 5rad / s, amplitude 0.1A, frequency 5rad / s, amplitude 0.1A, frequency 5rad / s and π phase angle are added to the segmented motor control circuit of each section respectively to simulate the torque fluctuation in the actual operation of the system. as Figure 7 It shows the motor output current response when using the traditional parallel independent controller, and the peak fluctuation is about 0.01A, as shown in Figure 8 It shows the motor output current response when the structure and method of the invention are adopted, the fluctuation peak value is reduced to 0.005a, and the phase is further reduced, which enhances the synchronization of each section of motor, and provides basic conditions for the control algorithm of suppressing periodic disturbance. as Figure 9 and Figure 10 It shows the response result of the system tracking speed command and the total current response of the system q-axis by using the method of the invention.
[0044] The above is only the preferred embodiment of the invention. It should be pointed out that for ordinary technicians in the technical field, several improvements and refinements can be made without departing from the principles of the invention, and these improvements and refinements should also be regarded as the protection scope of the invention.
