Control system and method for permanent magnet synchronous traction and transmission system

A control system for a permanent magnet synchronous traction and transmission system, for controlling of the permanent magnet synchronous traction and transmission system, wherein the control system comprises a sampling unit and a controller;

• the sampling unit is connected to a permanent magnet synchronous motor, and comprises:
• a current sensor for collecting an operation excitation current and an operation torque current of the permanent magnet synchronous motor, a voltage sensor for collecting a input capacitor voltage of the permanent magnet synchronous motor, and a resolver for collecting an initial rotor position and a rotor frequency of the permanent magnet synchronous motor;
• the controller comprises:
• an instruction acquisition unit, configured to acquire a target torque instruction issued to the traction and transmission system;
• a Maximum Torque Per Ampere (MTPA) calculation unit, configured to calculate a target excitation current value and a target torque current value according to the target torque instruction;
• a regulation unit, comprising:
• an excitation regulation unit and a torque regulation unit;
• the excitation regulation unit configured to generate an excitation current regulation value according to the target excitation current value and an operation excitation current value;
• and the torque regulation unit configured to generate a torque current regulation value according to the target torque current value and an operation torque current value;
• a decoupling control unit, configured to generate a target modulation ratio and a modulation frequency according to the excitation current regulation value and the torque current regulation value output from the regulation unit;
• a method for generating the target modulation ratio M is as follows:
• Us=√{square root over (Ud+Uq)}
• M
• =
• 3
• *
• (
• U
• s
• +
• PID
• .
• I
• d
• ⁢
• o
• ⁢
• u
• ⁢
• t
• )
• F
• ⁢
• c
• wherein Fc is the input capacitor voltage, and PID.Idout is an excitation current regulation value;
• Ud is a control voltage component of a shaft d, and Uq is a control voltage component of a shaft q;
• a method for generating the modulation frequency Fs_out is as follows:
• Fs_out=(1+PID.Iqout)*Fs
• wherein PID.Iqout is a torque current regulation value, and Fs is a rotor frequency;
• a segment synchronous modulation unit, configured to output a Pulse Width Modulation (PWM) modulation wave control signal for the permanent magnet synchronous motor, according to the target modulation ratio and the modulation frequency generated by the decoupling control unit;
• and
• the segment synchronous modulation unit receives the information of M and Fs_out, and generates a three-phase (u, v, w) pulse by determining a sector where a voltage vector is located.