In the design concept of DC motor drive circuit, we mainly consider the following points: Function: Does the motor rotate in one direction or two directions? Do you need to adjust the speed? For one-way motor drive, just use a high-power triode or field effect tube or relay to directly drive the motor. When the motor needs to rotate in both directions, you can use a bridge circuit composed of power components or use a double-pole double-throw. relay. If speed regulation is not required, just use a relay. But if speed regulation is required, switching elements such as transistors and field effect transistors can be used to achieve speed regulation (pulse width modulation).
Performance: For speed-regulated motor drive circuits, the main performance indicators are the following:
Output current and voltage range, which determine how powerful the motor can be driven by the circuit.
Efficiency, high efficiency not only means saving power, but also reducing the heat generated by the drive circuit. To improve the efficiency of the circuit, you can start by ensuring the switching working state of the power device and preventing common-state conduction (a problem that may occur in bridge or push-pull circuits, that is, two power devices are turned on at the same time to short-circuit the power supply).
Effect on control input. The power circuit should have good signal isolation at its input end to prevent high voltage and large current from entering the main control circuit. This can be achieved by using a high input impedance or a photocoupler to achieve isolation.
Impact on power supply. Common-mode conduction can cause an instant drop in the power supply voltage, causing high-frequency power supply pollution. Large currents may cause the ground potential to float.
Reliability. The motor drive circuit should be as safe as possible, no matter what kind of control signal or passive load is added.
After understanding the above design concepts of DC motor
drive circuit, you will be more comfortable during operation.
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DC motor drive circuit design concept