Overview
Current hysteresis is actually to compare the output current with the standard current. If the difference exceeds a certain value, it will change the conduction of the bridge inverter circuit. The hysteresis is a hysteresis characteristic used in the comparison process, which can be realized by the relay in Simulink. The whole system is a closed-loop system, and the controlled quantity is the output phase current. Why is the current controlled because the current is an important factor in determining the electromagnetic torque in motor control.
System Simulink block diagram
The size of the inductance must be adjusted appropriately, the current rises slowly when it is large, and it cannot keep up with the given ideal current. Too small and too fast. I give 0.1H, 1Ohm here.
The structure of the bridge component is as follows:
Scope1 is used to look at the pulse of the control current, which is generated by a current hysteresis subsystem, and the input of this subsystem is the actual output current of the bridge circuit. In this way, the control loop is formed.
Hysteresis subsystem
We analyze the bridge circuit and the theory of hysteresis tracking to know that each bridge arm of the bridge can only be connected at a certain time, so the upper and lower arms are complementary, so we take the opposite of each hysteresis output. The last six signals MUX immediately become our control pulses.
The convert here is to convert the data, and NOT is the inverse.
result
Output current:
control PWM:
