Simulation of Closed Loop Speed Control of BLDC Motor - MATLAB/Simulink

The outputs of the “Permanent Magnet Synchronous Machine” module include:

1.      stator Phase currents i_a, i_b and i_c.

2.      The phase back-EMF of the windings e_a, e­­_b and e_c.

3.      The output signals of Hall position sensors HA, HB and HC.

4.      The rotor speed n(rad/sec).

5.      The rotor position angle theta(rad).

6.      The electromagnetic torque Te(N*m).

The parameters of the motor mainly include:

1.      Stator resistance R(Ohm), inductance Ls(H).

2.      Flux linkage established by magnet (V.s)

3.      Voltage constant( V_peak L-L/krpm)

4.      Toque constant (N.m/A_peak)

5.      the back-EMF flat area(degree).

6.      moment of inertia J (kg m2),Viscous damping F(N.m.s),Number of pairs of poles P, Static friction Tf(N.m)

Ideal waveform of BLDC motor

SPEED CONTROLLER

            The speed controller is based on PI controller. The output of the regulator is torque set point applied to current controller block.

            Speed cutoff frequency

            The speed measurement first-order low-pass filter cutoff frequency (Hz). This parameter is used in speed regulation mode only.

        Speed controller sampling time

            The speed controller sampling time (s). The sampling time must be a multiple of the simulation time step.

    Speed Ramps — Acceleration

            The maximum change of speed allowed during motor acceleration (rpm/s). An excessively large positive value can cause DC bus under-voltage. This parameter is used in speed regulation mode only.

Speed Ramps — Deceleration

            The maximum change of speed allowed during motor deceleration (rpm/s). An excessively large negative value can cause DC bus overvoltage. This parameter is used in speed regulation mode only.

PI Regulator — Proportional Gain

            The speed controller proportional gain. This parameter is used in speed regulation mode only.

PI Regulator — Integral Gain

            The speed controller integral gain. This parameter is used in speed regulation mode only.

Torque output limits — Negative

            The maximum negative demanded torque applied to the motor by the current controller (N.m).

Torque output limits — Positive

            The maximum positive demanded torque applied to the motor by the current controller (N.m).

BRAKING CHOPPER SECTION

RESULT ANALYSIS

 FOR MOTOR SPEED AT +300RPM

                                                             

Phase Current, BEMF, Speed, Torque

Three Phase BEMF

DC Bus

Hall Signal

Phase Current

Speed, Torque

FOR MOTOR SPEED AT -300RPM

Phase Current, BEMF, Speed, Torque

All Phase BEMF

DC Bus

Hall Signal

Phase Current

Speed and Torque

FOR MOTOR SPEED IN BOTH FORWARD AND REVERSE (+300 rpm & -300 rpm)

Phase current, BEMF, Speed, Torque

All Phase BEMF

DC Bus

Hall Signal

Stator Phase Current

Speed and Torque