A control system of a flexible permanent magnet brushless DC motor, comprising a DC power supply, a filter capacitor, a voltage source inverter, a permanent magnet brushless DC motor and a controller, wherein the output end of the DC power supply is connected with the filter capacitor in parallel;
- the voltage source inverter is provided with m bridge arms which are connected with both ends of the filter capacitor in parallel;
- upper and lower controllable switches are arranged on each bridge arm;
- the phase number of armature winding of the permanent magnet brushless DC motor is equal to the number of bridge arms;
- head ends of armature windings of each phase are correspondingly connected with intermediate contacts of the upper controllable switch and the lower controllable switch of one bridge arm, tail ends of armature windings of each phase are connected together;
- an electrical angle 360° of the permanent magnet brushless DC motor is divided into a plurality of sectors;
- the controller determines the sectors corresponding to an N pole of a rotor according to the position of the rotor, and outputs a control signal in combination with the direction of the electromagnetic torque required by the motor to drive the corresponding controllable switch to be turned on or off;
- when the permanent magnet brushless DC motor is required to generate a counterclockwise rotation torque, the head ends of a n-phase armature windings under the N pole of the rotor are simultaneously conducted with a positive pole of the DC power supply, and the head ends of a n′-phase armature windings under a S pole of the rotor are simultaneously conducted with a negative pole of the DC power supply;
- when the permanent magnet brushless DC motor is required to generate a clockwise rotation torque, the head ends of the n-phase armature windings under the N pole of the rotor are simultaneously conducted with the negative pole of the DC power supply, the head ends of the n′-phase armature windings under the S pole of the rotor are simultaneously conducted with the positive pole of the DC power supply, and n+n′≤m wherein the armature windings of the permanent magnet brushless DC motor are single-layer armature windings;
- it may be assumed that one of the armature windings is numbered i, i=1, 2, . . . m, when i<m, the head ends of ith-phase armature windings and the tail ends of (i+1)th-phase armature windings are alternately arranged in sequence along a circumferential direction;
- when m is an even number, the head ends of mth-phase armature windings are adjacent to the head ends of first-phase armature windings, and the tail ends of the mth-phase armature windings are adjacent to the tail ends of the first phase armature windings;
- and when m is an odd number, the head ends of the mth-phase armature windings are adjacent to the tail ends of the first-phase armature windings, and the tail ends of the mth-phase armature windings are adjacent to the head ends of the first-phase armature windings.