The invention discloses a permanent-
magnet synchronous-motor open-winding fault-tolerant
direct torque control method based on improved SVPWM. The method comprises the following steps of when an
inverter switch tube has an open circuit fault,
cutting off connection between a motor port and the fault
inverter switch tube, connecting the motor port to a power supply midpoint, and using the remainingswitch tube to carry out fault-tolerant reconstruction on a
system topology; through a PI controller, outputting a given torque; using a ''current method'' to estimate a
stator flux linkage; and through the difference value of the given torque and an estimated torque, acquiring the variable quantity d
delta of a
load angle, using a
maximum torque current ratio control method to give a reference
stator flux linkage, and based on that, calculating a given reference
voltage vector. Through the remaining switch tube, improved spatial
voltage vector
pulse width modulation reconstruction is performed. A double-
inverter PWM
control signal with a fixed switch frequency is output to an inverter. Under the open circuit fault of the switch tube, the safe and stable operation of a
system under the fault is guaranteed, and the
system has a good
stable state and dynamic performance.