Control method and control system for motor
A control system and drive control technology, applied in the field of control, can solve problems affecting the reliability of system control and achieve the effect of preventing serious risks
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Embodiment 1
[0068] Such as figure 2 As shown, the method of controlling the motor includes:
[0069] Step S11, collect the bemf (Back Electromotive Force back electromotive force) value of the motor, and save it in the bemf register;
[0070] The theoretical formula of the bemf generated by the changing motor rotor magnetic field on the stator coil changes with the rotation speed of the motor rotor is:
[0071] bemf=-N×B×A×ωsinωt
[0072] Among them, N is the number of turns of the stator coil, B is the magnetic field strength of the motor rotor, A is the coupling area between the magnetic field of the motor rotor and the coil, and ω is the rotational angular velocity of the rotor. For a certain motor, N, B, and A are all constants, so the bemf amplitude is theoretically linear with the rotor speed, as image 3 shown. Therefore, the change of the bemf value can reflect the change of the rotation speed of the motor rotor; by collecting the bemf, the change of the rotation speed of the...
Embodiment 2
[0082] The method for controlling a motor as described above, the difference of this embodiment is that, as Figure 4 As shown, the step S11 includes:
[0083] Step S111, generating a clock signal through a reference clock;
[0084] By generating a clock signal, subsequent sampling moments can be selected so as to perform sampling within a specific time period.
[0085] Step S112 , sampling the voltage across the sampling coil within the zero-crossing time of the current of the sampling coil according to the clock signal, and storing the sampled voltage in the bemf register; the sampled voltage is the bemf value of the motor.
[0086] Wherein, the sampling coil is a motor stator coil.
[0087] The voltage expression on the stator coil of the motor is:
[0088]
[0089] V coil is the coil voltage, i is the coil current, R is the coil resistance, L is the coil inductance value, and bemf is the induced electromotive force generated on the coil by the change of the rotor ma...
Embodiment 3
[0094] As the method for controlling a motor described above, the difference in this embodiment is that the step S111 further includes delaying the clock signal;
[0095] Figure 20 Between T1 and T2 is the zero-crossing time of the coil current. The dotted line is the theoretical value, and the solid line is the actual value. Due to the energy storage characteristics of the coil, when the driving module driving the coil is turned off (time T1), the current in the coil will not be 0 immediately, but it will take a certain period of time before it becomes 0 (time Tdecay). Due to the existence of this characteristic, the actual bemf value is the coil voltage value after Tdecay time. Such as Figure 21 As shown, S10 and S27 are respectively the first and last coil voltage sampling of this current zero crossing. From S10 to S14, the selected coil voltage value includes the voltage generated by the coil current in addition to bemf; after S14, the original energy storage in the ...
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