Brake device of variable frequency fan and control method of brake device

The invention discloses a brake device of a variable frequency fan and a control method of the brake device. The brake device comprises a conversion circuit, the variable frequency fan, a variable frequency fan starting circuit, a driving controller, a brake enabling circuit and a brake release circuit. The brake enabling circuit can guarantee the variable frequency fan to be in a stop state before starting, so that the variable frequency fan is not subjected to burnout or starting incapability due to external force reversion; the brake device use simple electronic elements, such as diodes, resistors and capacitors, and can realize brake protection before starting of the variable frequency fan, brake release after brake stop and starting operation of the variable frequency fan; the reliable and effective control of brake protection, brake release and starting operation can be achieved under the condition of simple circuit design; and the brake device can be suitable for a control topological structure of a similar permanent magnetic variable frequency motor.