37results about How to "Reduce waveform distortion rate" patented technology

A permanent-magnet synchronous motor provided with a rotor structure having cage-type windings and a permanent magnet disposed on the inner peripheral side of the cage-type winding bar, wherein the permanent magnet is magnetized to provide a ratio theta / alpha of 0.54 through 0.67 between the peripheral-direction pitch angle theta of the permanent magnet's magnetic flux distribution and a magneticpole pitch angle alpha so as to ensure a required induced electromotive force with no increase in iron loss and to reduce a waveform distortion rate. Accordingly, a high-efficiency permanent-magnet synchronous motor can be provided due to an induced electromotive force having little distortion and a shape of nearly a sinusoidal wave.

The invention relates to the field of mechanical and electrical technology, in particular to a single-phase voltage-regulating winding of a rare earth generator. The single-phase voltage-regulating winding of the rare earth generator adopts sine windings, the sine winding at one electrode is connected with a concentric winding with equal turns of each slot in series, and each electrode is respectively provided with a tap. The single-phase voltage-regulating winding is characterized in that a voltage-regulating winding is connected with the sine winding of each electrode at the maximum pitch in series, and each voltage-regulating winding is respectively provided with the tap, wherein, the number of coil turns of the voltage-regulating winding at one electrode is twice of that of the voltage-regulating winding at the other electrode. The single-phase voltage-regulating winding of the rare earth generator can improve the waveform, and the waveform distortion rate is less than 5 percent.

The invention discloses a high-efficiency and wide-range programmable inverter power supply device and a control method thereof. Among them, the device includes a main circuit unit, the input end of which is connected to the mains, and the mains is converted into a DC signal by a filter, a rectifier and an inverter in turn to supply power to the load; the rectifier and the inverter are respectively connected to the programmable control unit; The programmable control unit is configured to preset the effective value of the voltage, and make a difference between it and the effective value of the voltage sampling feedback to obtain the voltage error; adjust the voltage error through PI to generate a PI adjusted voltage amplitude signal; adjust the PI voltage The amplitude signal is multiplied by the sine wave signal generated by the phase-locked output voltage of the filter to obtain a sine modulation voltage signal; the sine modulation voltage signal is subtracted from the received voltage instantaneous feedback signal, and then adjusted by PI and pre-set Multiply the proportional coefficients to obtain the SPWM voltage pulse width signal; the SPWM voltage pulse width signal is used to drive the switching tube in the rectifier, and finally generate a voltage waveform with a preset amplitude and frequency.

The invention provides a control method for improving the commutation accuracy of brushless DC motors. The difference in the number of interrupts between two conduction sections is taken as a feedbackvalue of the input end of a PI controller, and PI control is carried out to make the difference in the number of interrupts follow a reference value. The compensation angle obtained through PI control on the difference in the number of interrupts changes according to the actual commutation state. Whether the current motor commutation is ahead or lags behind is determined according to the symmetryof the slopes on the two sides of the trapezoidal terminal voltage wave, and then, the phase compensation is adjusted, so as to improve the accuracy of commutation. On the basis of the original sensorless brushless DC motor control system, the cycles maintained on each of the two sides of the trapezoid wave of each phase of counter electromotive force are counted, and phase compensation is carried out according to the difference in the number of count points between the two sides. The control method does not need an additional hardware circuit, is simple, and can improve the accuracy of commutation, reduce the waveform distortion rate of the voltage and current of the motor and reduce the torque ripple.

An automatic calibration device for an AC voltage divider, including an industrial computer system connected in sequence, a broadband high-stable power supply, an intermediate frequency step-up transformer, a standard broadband voltage divider, and the standard broadband voltage divider is used for parallel connection with the AC voltage divider to be tested . The industrial computer system is used to send control signals to control the frequency and amplitude of the output voltage of the broadband high-stable power supply according to the preset voltage detection point, to sample the voltage of the standard broadband voltage divider, and to adjust the standard broadband voltage divider by feedback automatic control The error between the voltage at the high-voltage end and the target set voltage, when the voltage at the high-voltage end of the standard broadband voltage divider reaches the preset voltage detection point, the boost will automatically stop; the intermediate frequency step-up transformer is used to boost the output voltage of the broadband high-stable power supply Then output to the standard broadband voltage divider and the AC voltage divider to be tested. The invention has stable output voltage, small waveform distortion rate, and small frequency deviation, which can avoid reading changes of resistive-capacitive voltage dividers caused by voltage quality problems. The entire detection and calibration process is fully automatic, and manual or mechanical voltage regulation can be avoided. Process operation error.

The invention discloses a current synergistic control method for the upper and lower busbar currents of current source rectifiers in parallel operation. The upper and lower busbar currents of two rectifiers are sampled and filtered, and then the error between the output current and the reference current of the upper busbars of the two rectifiers is sent to the The proportional integral controller is used for adjustment to obtain the delay angle required for modulation. In addition, the difference of the lower bus current is sent to the proportional integral controller to calculate the bypass pulse width control parameter. The combination of the two can flexibly adjust the output current of the upper and lower bus, and realize the coordinated control of the upper and lower bus currents when the rectifiers are connected in parallel. Purpose.