14results about How to "Reduce harmonic current" patented technology

The invention discloses a torsional vibration suppression strategy for an electric drive system based on a double-layer model predictive control, and relates to the technical field of electric vehicle motors. The invention establishes a mathematical model of a permanent magnet synchronous motor taking into account the dynamic characteristics of the motor based on a stator voltage equation in a d-q coordinate system; based on the dynamics of a gear system, a 19-degree-of-freedom gear transmission system model is established taking into account nonlinear factors such as time-varying meshing stiffness, meshing error, and tooth side clearance; based on the model of the electric drive system, a torsional vibration suppression strategy based on a double-layer model predictive control is proposed, which suppresses the torsional vibration of an integrated electric drive system by controlling the motor target torque and reducing current harmonics and torque fluctuations, thereby enhancing the stability of the electric drive system and improving the comfort of the whole vehicle.

The invention discloses a permanent magnet synchronous motor inverter nonlinear error compensation method, which comprises the following steps of: inputting an input capacitor of an insulated gate bipolar transistor (IGBT) and an output capacitor of the insulated gate bipolar transistor (IGBT) into a voltage error mathematical model; estimating a first coefficient, a second coefficient, a third coefficient and a fourth coefficient in the voltage error mathematical model by using an algorithm of a linear neural network; the first coefficient, the second coefficient, the third coefficient and the fourth coefficient in the voltage error mathematical model obtained through estimation are input into the voltage error mathematical model, and the nonlinear voltage error of the permanent magnet synchronous motor inverter is obtained through output of the voltage error mathematical model. According to the invention, the dead zone effect, the switch tube turn-on delay, the switch tube turn-off delay, the switch tube and diode turn-on voltage drop and the stray capacitance effect are comprehensively considered, an accurate voltage error mathematical model is established, and accurate voltage compensation can be realized.

The invention relates to the technical field of motor control, and particularly discloses a permanent magnet synchronous motor stability control method, which comprises the following steps of: adjusting parameters of a PI regulator 1 and a PI regulator 2 to enable feedback dq axis current of a motor to follow given; a harmonic extraction module is operated, current harmonics of all times are obtained, harmonic currents id.xth and iq.xth are obtained through calculation, and x is an odd number which is not three times; calculating to obtain an effective value is.xth of each current harmonic wave; when is.xth is larger than the judgment threshold value delta I, the enabling coefficient Mx is equal to 1; when is.xth is smaller than or equal to the judgment threshold value delta I, the enabling coefficient Mx is equal to 0; adding a harmonic processing module, and operating the permanent magnet synchronous motor; operating a harmonic extraction module, and adjusting a gain coefficient Kx according to the distribution condition of each current harmonic; according to the invention, the current harmonics of each time of the motor are effectively combed, the current harmonics of the motor are reduced in a targeted manner, the torque ripple is reduced, and the stability of motor control is improved.

The invention belongs to the technical field of motor control, and particularly relates to a vector control method of a synchronous motor, which comprises the following steps of: obtaining a relationship between virtual current deviation and virtual voltage deviation in a vector control intermediate process; finding a voltage vector deviation closest to the virtual voltage deviation from all probabilities of the voltage vector deviation of the current period relative to the voltage vector deviation of the previous period, performing sum operation on the voltage vector deviation and a reference value of the voltage vector of the previous period to obtain a reference value of the voltage vector of the current period, acting the reference value on a bridge arm of a motor inverter, and changing the on-off state of the inverter. Vector control over the motor is achieved, and the dependence of an algorithm on motor parameters is reduced by circularly using the current of the previous period. The method can greatly reduce the amount of data needing to be calculated, improves the control efficiency and precision, and is suitable for speed regulation of the synchronous motor. The invention also provides a non-transitory readable recording medium storing the program of the method and a system comprising the medium, and the program can be called through a processing circuit to execute the method.

The invention relates to a frequency conversion cooperative starting control method for a motor of a ship emergency power system. The method comprises the following steps: step 1, modeling of the ship emergency power system: establishing an optimal configuration model of a ship comprehensive power system based on multiple constraint conditions of operation economy, system operation safety and power distribution rapidity of a diesel generating set; step 2, load starting conditions of the high-power motor: when the number of pole pairs of a motor winding is fixed, the starting torque of the motor can be adjusted by changing the terminal voltage and the power supply frequency; and 3, AFE control is adopted for a rectification part, and V / F control is adopted for an induction motor. The problem that an existing motor starting control method is not suitable for a ship emergency electric power system and cannot meet the requirement of a high power factor is solved, the alternating voltage generated by the AFE can still be kept in a stable state, the frequency conversion control mode is more stable, and the reliability is higher. The method is more suitable for stabilizing the condition of high ship pulse load power change, and the stability of a ship emergency power system is further improved.

The application discloses a carrier frequency control method, a control device and an air conditioner for power factor correction, wherein the carrier frequency control method is a special carrier frequency control method used near the zero-crossing point of the variable carrier frequency control method; for the carrier frequency corresponding to the input voltage / input current near the zero-crossing point, the carrier frequency is limited to a fixed value or is increased with the decrease of the input voltage / input current, so that the input current of the PFC circuit near the zero-crossing point cannot follow the input voltage, the current harmonic of the PFC circuit is reduced, and the working stability of the PFC circuit is improved.

The invention discloses a nine-phase permanent magnet synchronous motor multi-space harmonic current suppression method based on a virtual voltage vector, and belongs to the technical field of multi-phase motor control. The method mainly comprises the following steps of: 1, performing vector space decoupling on a nine-phase system, and selecting four groups of totally 72 basic voltage vectors as a basic control set; 2, according to a volt-second balance principle, corresponding virtual voltage vectors with mapping amplitudes of 0 in other spaces are constructed in the three harmonic spaces; and 3, analyzing phase current distribution characteristics under a harmonic open-loop control method, and formulating a duty ratio optimal distribution rule for preferentially suppressing third harmonics. And 4, judging sectors of the reference voltage vectors in the fundamental wave space and the three harmonic wave spaces, and outputting the sectors after reasonable optimization distribution of the duty ratio. By utilizing the constructed virtual voltage vector and duty ratio optimization distribution rule, the full-space closed-loop control can be realized when the modulation degree is low, and the third harmonic can be preferentially suppressed when the modulation degree is high, so that the current quality is greatly improved.

The invention discloses a magnetic suspension bearing high-frequency vibration suppression method and system based on carrier phase-shifting PWM. The method comprises the steps that the carrier phase-shifting angle of each driving winding of a magnetic bearing is regulated and controlled; the switching frequency of PWM control is adjusted, and a vibration response minimum point is found; or the carrier phase shift angle of each driving winding of the magnetic bearing is regulated and controlled, the switching frequency of PWM control is regulated, and the vibration response minimum point is found. The method comprises the following steps: designing an experiment, collecting vibration data under different phase shift angles and switching frequencies, training a deep neural network prediction model, establishing a mapping relation between PWM regulation and control parameters and vibration magnitude, and further performing joint optimization on the PWM regulation and control parameters (phase shift angles and switching frequencies of carrier waves of windings). By regulating and controlling the carrier phase-shifting angle and the switching frequency, the vibration of the high-frequency switching frequency of the magnetic bearing is reduced by more than 80%, the current ripple amplitude of a direct-current bus is reduced by 80%, and meanwhile, the harmonic current of a magnetic bearing winding and the rotor displacement control precision are not influenced.

The invention discloses a multiplexing control method and device for an active filtering function of a network-forming inverter. The method comprises the following steps: acquiring real-time operation parameters of an inverter; wherein the real-time operation parameters at least comprise grid-side current, grid-connected point voltage and capacitor voltage of a filter capacitor; determining a reference voltage corresponding to the inverter according to the grid-side current, the capacitor voltage and a preset working parameter; respectively extracting harmonic components corresponding to the capacitor voltage and the grid-connected point voltage to obtain a corresponding capacitor voltage harmonic component and a grid-connected point voltage harmonic component; determining a reference voltage harmonic component according to the capacitor voltage harmonic component and the grid-connected point voltage harmonic component; determining a target control parameter according to the capacitor voltage, the reference voltage and the reference voltage harmonic component; and controlling a switching device of the inverter according to the target control parameter. The active filtering function is seamlessly integrated in the topological structure of the existing network-forming inverter, so that the harmonic compensation of a local nonlinear load can be realized, and meanwhile, the application scene is wide.

The invention discloses a three-phase circuit step-down power factor correction digital control method, which belongs to the technical field of circuit control, and specifically comprises: after the three-phase alternating current is connected to a power supply, it is subjected to EMI filtering for interference suppression, and one path of the three-phase alternating current is input into a double-BUCK conversion circuit after passing through a rectifier bridge, and the double-BUCK conversion circuit comprises a power factor correction circuit and a DC / DC conversion circuit; after the three-phase alternating current is output from the double-BUCK conversion circuit, it is subjected to an output filtering circuit to reduce ripples, and then an input voltage sampling circuit is used to generate a voltage sampling signal, and the voltage sampling signal is input into a DSP control circuit to judge whether the input voltage is a voltage; when an input voltage abnormality signal is generated, the power factor correction circuit and the DC / DC conversion circuit are controlled to work at the same time; and a soft start circuit in the power supply is controlled to gradually increase the voltage on the high-voltage side capacitor to a preset voltage; the power factor correction circuit of the invention realizes the reduction of the reactive power loss of the circuit.

The invention relates to the technical field of circuit control, in particular to a motor control method and device based on three-level inversion, computer equipment and a storage medium. The method comprises the following steps: determining target circuit information corresponding to the current moment of the three-level inverter; performing control parameter analysis on the target circuit information to obtain a control parameter corresponding to the permanent magnet synchronous motor; and performing motor control on the permanent magnet synchronous motor according to the control parameters. According to the invention, while the problem of neutral-point potential imbalance of the three-level inverter is considered, the control precision of the motor can be improved, the current harmonic of the motor can be reduced, and the torque ripple of the motor can be reduced by adopting the three-level inverter, double-vector control, variable-period online calculation and other forms.

The invention discloses a synchronous motor control method and device, electronic equipment and a storage medium, and the method comprises the steps: obtaining the switching state of an inverter of a permanent magnet linear synchronous motor according to a preset period when the permanent magnet linear synchronous motor is in an operation state, and determining an output voltage vector plane according to the switching state of the inverter; dividing the output voltage vector plane according to preset division times to obtain each divided virtual voltage vector; obtaining operation parameters of the permanent magnet linear synchronous motor, and obtaining an optimal voltage vector according to the operation parameters, each virtual voltage vector and a predetermined current prediction model; and controlling the permanent magnet linear synchronous motor based on the optimal voltage vector. The method has the advantages that the flexibility and adaptability of motor control are improved, and different motor operation states can be better coped with.

The invention discloses a permanent magnet synchronous motor and a single-resistor current sampling method. The permanent magnet synchronous motor controls a three-phase inverter based on an SVPWM strategy, and the method comprises the following steps: in a current control period, acquiring flow directions of A, B and C three-phase current; according to the flow direction of the ABC three-phase current and a sector where a target voltage vector is located, whether the minimum time window of single-resistor sampling in the current control period can cancel dead time or not is determined; and according to the determined minimum time window, determining whether to adjust the two-phase sampling in the current control period. According to the scheme provided by the invention, sampling can be carried out by directly utilizing the dead time under some conditions, so that the number of times of PWM waveform adjustment is reduced, the stability of the system is improved, and the collected current is closer to the same moment.

The utility model discloses a special high-performance four-quadrant frequency converter for the electromagnetic industry, which belongs to the technical field of power electronics, and comprises a main topology part and a control part, the main topology part comprises an input filtering part, a rectification filtering part and an inversion part, the input filtering part comprises a network side inductor L1, a filtering capacitor C1 and a machine side inductor L2, and the rectification filtering part comprises a three-phase half-bridge insulated gate bipolar transistor module, a first bus capacitor Cd1, a second bus capacitor Cd2, a first voltage-sharing resistor Rd1, a second voltage-sharing resistor Rd2 and a buffer loop. The inversion part comprises one or three paths of three-phase half-bridge insulated gate bipolar transistor modules, and the control part comprises a power supply board, a detection board, a rectification side main control board, an inversion side main control board, a rectification side driving board, an inversion side driving board and a driving board.