32results about How to "Avoid overcurrent faults" patented technology

The invention discloses a crossing control device, system and method for train pantograph-catenary disconnection. The device comprises a pantograph-catenary disconnection detecting unit, a rectification control unit and an inverter control unit. The pantograph-catenary disconnection detecting unit is used for detecting the pantograph-catenary disconnection state of a train; the rectification control unit is used for controlling a rectifying module to realize stable direct voltage of a middle DC circuit when the train is in normal operating conditions; the rectification control unit is used forcontrolling the rectifying module to realize stable primary voltage of a traction transformer when the train is in pantograph-catenary disconnection conditions; the inverter control unit is used forcontrolling an inverter module to realize the consistency of output torque of a traction motor and the given torque when the train is in normal operating conditions; the inverter control unit is usedfor controlling the inverter module to realize the stable direct voltage of the middle DC circuit when the train is in pantograph-catenary disconnection conditions. The crossing control device, system, andmethod disclosed by the invention can solve the technical problems that transformer primary overcurrent fault or four-quadrant AC side overcurrent fault as well as DC voltage shortage or auxiliary transformer shutdown fault in a traction system can be easily caused in pantograph-catenary disconnection, in particular to arc-free pantograph-catenary disconnection.

The invention discloses a current-limiting and controlling method of active damping of a current-limiting and tank circuit. The output of a first half bridge (HB1) of a first current source inverter (CSC1) has the same phase with a first filter capacitor (C1) and the current with the amplitude of 1 / R; the output of a second half bridge (HB2) of the first current source inverter (CSC1) has the same phase with a second filter capacitor (C2) and the current with the amplitude of 1 / R; the output of a third half bridge (HB3) of the first current source inverter (CSC1) has the same phase with a third filter capacitor (C3) and the current with the amplitude of 1 / R; or the output of the first current source inverter (CSC1) has the same phase with the first filter capacitor (C1) and the current with the amplitude of 1 / R; the output of a second current source inverter (CSC2) has the same phase with the second filter capacitor (C2) and the current with the amplitude of 1 / R; and the output of a third current source inverter (CSC3) has the same phase with the third filter capacitor (C3) and the current with the amplitude of 1 / R. In the invention, open-loop control is needed only and the response speed is nearly instantaneous.

The invention discloses a method for preventing overcurrent of a three-phase motor, comprising: performing inverse Park transformation and inverse Clark transformation on the obtained D-axis demand current and Q-axis demand current to obtain the three-phase current of the motor; when the three-phase current When the preset three-phase current threshold is exceeded, the three-phase current is corrected to obtain the corrected three-phase current; Park transformation and Clark transformation are performed on the corrected three-phase current to obtain the corrected D-axis demand current and Q-axis demand current; When the absolute value of the motor speed is less than the preset speed threshold, output the corrected D-axis demand current and Q-axis demand current; when the absolute value of the motor speed is greater than the preset speed threshold, reacquire the D-axis demand current and Q-axis according to the formula shaft demand current, repeat all the above steps. Through the above method, the motor can avoid the overcurrent fault.

The invention discloses a current control method for automatically judging the current state of a switch reluctance motor. The method comprises the following steps: judging whether the reluctance motor is in an electric state or a generating state by judging the relation between the actual current of a phase coil winding and upper and lower given currents; then controlling the on / off of switch tubes inside a power switching circuit according to the result of the judgment, alternately turning off a single switch tube to limit current when the reluctance motor is in the electric operation state,and turning off two switch tubes when the reluctance motor is in the generating state to feed back energy to a bus capacitor, so that overcurrent faults caused by the fact that the off of the switchtubes is not controlled in time are avoided. The judgments for the electric and generating states depend on current signals, and external signals are not needed, so that the circuit structure is simplified, and the operation efficiency is improved.

The invention discloses a protection device and method for an electric vehicle air compressor energy supply system. The method includes: detecting the current state of the air compressor energy supply system; starting a first current limiting mode when the current state is an overshoot state, wherein the air compressor energy supply is reduced in the first current limiting mode The output frequency of the system. According to the device of the present invention, the overcurrent fault of the functional system of the air compressor of the electric vehicle can be avoided, thereby greatly improving the stability and safety of the electric vehicle; compared with the prior art, the device of the present invention is simple in structure, easy to implement, and has the advantages of High practical value and promotion value.