1. There is a big difference between brushed and brushless. It's much easier to have a brush. You can turn it by giving it a DC voltage. If there is no brush, the voltage needs to be turned on and off by power electronic equipment, and the rhythm of the switch needs to be judged according to the position of the rotor, so the control requirements are more complicated. To put it bluntly, brushless DC is essentially an AC motor that eats square waves. However, the control of small brushless motor is very mature, and the fans in the computer are all brushless DC. 2. If driven, the brushed motor needs a DC-DC converter. Step-down, step-up, half bridge, etc. As long as it is an adjustable DC voltage. Even if it is 220 volts->; Adjustable transformer->; Any rectifier will do. The 500W motor is really a small motor, not a high power. Therefore, the speed can be controlled only by adjusting the pressure. Generally, the speed bandwidth can be adjusted in a few seconds. Of course, if it is above 5kW, or torque control is needed, it is necessary to control the current. The current control is a little more complicated, but the response is very fast, and a few milliseconds is enough for torque adjustment. If the speed is adjusted, the bandwidth will be tens of milliseconds. Brushless motors are much more complicated. Generally, at least one three-phase H bridge is needed. Control is divided into sensor control and sensorless control. Under the control of the sensor, the rotor position is measured by the sensor, and then the corresponding square wave voltage is provided to the stator. But the sensor is very expensive, which may not be much cheaper than your motor. Sensorless control needs a control algorithm to calculate the rotor position through the voltage on the no-load stator winding. There are many master's theses on this subject. If you want to do it, you must read it to understand it. 3. isolation. No power supply circuit needs optocoupler isolation. But isolation will make the circuit very stable and not easy to be damaged by overvoltage. And the level can be adjusted. So it is still recommended. The signal from the single chip microcomputer is isolated by optical coupler, and then sent to the gate drive chip and then to the power switch. Of course, companies like AD also provide isolation+driver integrated chip ADUM series, which has excellent performance, but the price is relatively high. Isolation is used for power electronic drive and has nothing to do with motor. After all, optocouplers cost money. If it is a 30-volt or 50-volt circuit, as long as the circuit design is reasonable, there is no problem without optocoupler. If the voltage is higher, an optocoupler will be used. Personal advice. 4. others. The circuit loss of 500W is about 10-20 W, which is related to your voltage and current level. If you want to do it yourself, heat dissipation should be considered. In addition, the circuit protection should also be done well. The motor is equipped with an inductor and a rotating rotor. Among them, the inductance is afraid of open circuit, which may produce very high instantaneous voltage, while the rotor will produce continuous voltage, which is afraid of short circuit. If the energy on these two parts is not well controlled, the circuit may explode.