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

The invention provides a motor control method and device, and a computer readable storage medium, used for solving the problem that the motor control is not accurate enough in related technologies. The motor control method comprises the following steps: sampling the current rotating speed and current of a motor; adjusting a first proportional parameter and a first integral parameter of a first proportional integral controller according to a rotating speed difference value between the rotating speed and a preset target speed; inputting the rotating speed difference value into the first proportional integral controller after adjusting the parameters to obtain a target current; inputting a current difference value between the current and the target current into a second proportional integralcontroller to obtain a target duty ratio; and inputting the target duty ratio to a PWM signal generator, so that the PWM signal generator outputs a motor control signal according to the target duty ratio.

The invention discloses a two-stage matrix converter based starting/generating system and a control method thereof. In the system, a starter/generator is disposed on a unidirectional switch side of a converter, and a starting power source and a load are disposed on a bidirectional switch side. On hardware, only a switch needs to be arranged between the starting power source and the load to achieve switching from a starting state to a generating state; during state switching, control algorithms need not to be changed too much; the whole starting/generating system has the advantages of compact structure, efficiency and reliability, achieves starting/generating integrated operation easily, and is suitable for aviation starting/generating systems.

The invention relates to a motor drive control method, a control device and a parking air conditioner controller. The method comprises steps of obtaining a q-axis current and a motor speed estimationvalue generated by a controller; determining a back electromotive force harmonic compensation value; determining q-axis given voltage according to the q-axis given voltage initial value and the counter electromotive force harmonic compensation value generated by the controller; and finally, carrying out voltage space vector pulse width modulation according to the voltage sum of the two-phase static coordinate system and the direct-current bus voltage, and generating a modulation signal used for driving an inverter so as to control the motor to operate. Counter electromotive force harmonic extraction and compensation in the control process are added; therefore, the phase current waveform peak of the winding of the motor in the operation process is reduced, the current is closer to sine, theloss and heating of the motor are reduced, the overcurrent fault in the rated load operation process is avoided, and the stability and reliability of the whole motor in the driving operation processare enhanced.

The invention discloses a control method and system of a train power supply system. The control method comprises the steps that a train power supply management cabinet sends a starting signal to N train power supply units; each train power supply unit executes the following steps: an FPGA module in the train power supply unit starts timing when receiving the starting signal; a control module of each train power supply unit controls a charging contactor and a short-circuit contactor to be switched on when receiving the starting signal, and controls the charging contactor to be switched off after a first preset time TC; the FPGA module sends a switch closing command after a second preset time TS; after receiving the switch closing command, a DSP module of each train power supply unit controls the switch of the train power supply unit where the DSP module is located to be closed; and the control module controls a four-quadrant rectification module to start after the closing time of the switch reaches a third preset time Ti. According to the invention, the oscillation current between the train power supply units is reduced, the overcurrent fault is avoided, and the impact on the trainload is reduced.

The invention provides a control method and a control apparatus for a motor, and a fan. The control method for the motor comprises the steps of detecting whether the phase current of the motor reaches a zero crossing point or not; and when it is detected that the phase current of the motor reaches the zero crossing point, adjusting the d-axis voltage of the motor to enable the phase voltage of the motor to be consistent with the phase of the phase current. By adoption of the technical scheme, the optimization of the motor efficiency can be ensured to satisfy the energy-saving control requirement; in addition, a hardware circuit also can be simplified, and the production cost of the product can be lowered; and meanwhile, the reliability and the stability of the product also can be improved.

The invention discloses a method for synchronizing a distributed power supply and a power grid and particularly relates to a method for solving voltage fluctuation in the connection of the distributed power supply to the power grid. In the method, a detection module contrasts the voltages of the distributed power supply and the power grid, the power grid is connected to if the voltage difference is within an error range, and the value of the voltage value needed to be regulated is calculated, the output of a grid-connected inverter is regulated and the distributed power supply can be connected to the power grid if the voltage difference is beyond the error range. The method realizes the seamless combination of a distributed power supply system and the power grid and the quick and accuratedetection of the frequencies, amplitudes and phases of the voltages of the distributed power supply system and the power grid, and when a grid connection condition is met, accurately sends a grid connection signal to realize seamless and quick grid connection. The alternating current of the grid-connected inverter is used as a grid connection feedback signal and the output current of the grid-connected inverter is made as close to zero as possible to prevent overcurrent faults from appearing before grid connection, so equipment is protected.

The invention provides a parallel inverter system, a wave-by-wave current limiting control method and an interface board. The parallel inverter system comprises a plurality of inverters connected in parallel and a plurality of interface boards, and each inverter is connected with an interface board. The plurality of interface boards form a loop in series; Each of the interface boards outputs a wave-by-wave current-limiting trigger signal to the latter interface board when receiving a wave-by-wave current-limiting trigger signal of the inverter connected thereto or a wave-by-wave current-limiting trigger signal output from the previous interface board, and simultaneously blocks a driving signal of the inverter connected thereto. The invention can avoid the hardware overcurrent fault of other inverters caused by the wave-by-wave current limiting of one inverter in the parallel inverter system by connecting the interface board in series into a loop and synchronizing the wave-by-wave current limiting triggering signal through the loop.

The invention discloses a method for preventing overcurrent of a three-phase motor. The method comprises the steps: carrying out reverse Park conversion and reverse Clark conversion on obtained D-axisrequired current and obtained Q-axis required current to obtain a three-phase current of a motor; when the three-phase current exceeds a preset three-phase current threshold, correcting the three-phase current to obtain a corrected three-phase current; carrying out Park conversion and Clark conversion on the corrected three-phase current to obtain corrected D-axis required current and Q-axis required current; when the absolute value of the rotating speed of the motor is smaller than a preset rotating speed threshold value, outputting the corrected D-axis required current and Q-axis required current; and when the absolute value of the rotating speed of the motor is greater than the preset rotating speed threshold, obtaining the D-axis required current and the Q-axis required current againaccording to a formula, and repeatedly executing all the steps. Through the method, overcurrent faults of the motor can be avoided.

The embodiment of the invention provides an OBC and DC/DC integrated charger, a control method and related equipment, the OBC and DC/DC integrated charger comprises an OBC, an OBC controller, a vehicle-mounted controller and a DC/DC converter, a first output end of the DC/DC converter is connected with an input end of the vehicle-mounted controller, a second output end of the DC/DC converter is connected with a low-voltage output end, and the OBC controller is connected with the vehicle-mounted controller. The first output end of the vehicle-mounted controller is connected with the first input end of the OBC controller, the second output end of the vehicle-mounted controller is connected with the second input end of the OBC controller, the third output end of the vehicle-mounted controller is connected with the first input end of the DC/DC converter, and the output end of the OBC controller is connected with the first input end of the OBC controller. According to the invention, the resonant cavity current of the OBC can be adjusted in time when the load of the electric equipment at the DC/DC output end is suddenly increased, so that the input current of the OBC is prevented from exceeding the limitation of the charging gun, and an overcurrent fault is avoided.

The invention relates to a metal mixer tilting system comprising a tilting reduction box connected with a metal mixer. The tilting reduction box is connected with a driving motor and a driven motor; the driving motor and the driven motor are respectively connected to a driving frequency converter and a driven frequency converter, wherein the tilting reduction box also comprises a PLC controller used for transmitting starting and rotating speed instruction to the driving frequency converter; the driven frequency converter comprises a rotating speed receiving device connected with an optical fiber master/slave ring net, wherein the rotating speed receiving device is used for receiving the rotating speed information of the driving frequency converter sent by a rotating speed transmitting device of the driving frequency converter and enabling the driven frequency converter to run at the rotating speed being the same as that of the driving frequency converter, thereby ensuring the output torque height of the two motors respectively connected with the driving frequency converter to be consistent, and therefore, the overcurrent failure of the frequency converter and the overvoltage failure of a DC loop of the frequency converter can be avoided.

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 present invention belongs to the electrical equipment protection technical field and relates to an anti-overcurrent device. The anti-overcurrent device is characterized in that the anti-overcurrent device comprises a main body; an anti-overcurrent circuit is arranged in the main body; the anti-overcurrent circuit is connected with the power supply line of electrical equipment; the anti-overcurrent circuit comprises a first self-recovering fuse and a first varistor which are connected in parallel; the surface of the first varistor is provided with a first contact sheet; an auxiliary limiting mechanism is welded onto the first contact sheet; and the auxiliary limiting mechanism is used for cutting off the control circuit of the electrical equipment. The anti-overcurrent device of the invention has the advantages of scientific and reasonable design, simple structure, high safety and high reliability. With the anti-overcurrent device adopted, the problem of too high instantaneous current which often appears in the production process of existing small and medium-sized old factories can be solved.