6results about How to "Reduce Harmonic Distortion Rate" patented technology

This invention discloses a method for adjusting the operating mode of a floating multi-energy complementary power generation platform system. The method includes setting the wave energy generation unit to MEC mode; setting the photovoltaic power generation unit to MPPT mode; setting the grid-side inverter unit to current source mode (VOC control mode); setting the energy storage unit converter to power generation fluctuation smoothing mode, and switching the charging and discharging states of the energy storage unit through constant power control; setting the wave energy generation unit to MEC mode or shutdown operation mode; setting the photovoltaic power generation unit to MPPT mode or constant voltage control mode; setting the grid-side inverter unit to VF control mode; and setting the energy storage unit converter to DC bus voltage stabilization control mode. This invention reduces transmission losses while minimizing the power impact on the main grid during the grid-connected operation of the island microgrid based on the power generation platform, thus improving the system's operational reliability.

The present application relates to a kind of functionization outer diameter unequal thickness magnetic ring and its magnetizing method, belong to permanent magnet motor technical field, the inner diameter of unequal thickness magnetic ring is circular, and the outer diameter is change curve, wherein, the change curve of outer diameter is constant in main magnetic pole portion thickness, and the thickness is reduced in the transition position between adjacent main magnetic pole portion;The unequal thickness magnetic ring adopts bonded neodymium iron boron material.The present application is composed of a functionization outer diameter bonded neodymium iron boron magnetic ring and its matching multipole magnetizing fixture, wherein the outer diameter of magnetic ring adopts two kinds of functionization size, by reducing the thickness of magnetic pole transition area, the harmonic component of surface magnetism of magnetic ring is controlled, and the amplitude of cogging torque is reduced.The multipole magnetizing core of matching magnetizing fixture can magnetize magnetic ring into surface alternately distributed multiple magnetic poles.

The application discloses a three-phase E-type hybrid level double-output integrated converter and a carrier PWM modulation method thereof, and belongs to the technical field of power electronic conversion devices. The three-phase E-type hybrid level double-output integrated converter comprises one DC input power supply, two capacitors on the DC input side, 15 switch modules, and one set of three-phase inductive load on each output end of the bridge arm of each phase. The carrier PWM modulation method with added DC offset and zero sequence component is given for the proposed converter. Two sets of modulation waves with added DC offset and zero sequence component are compared with anti-phase stacked carriers respectively. According to the switch state and the comparison result, the logic operation for generating the driving signals of each switch module is derived. One set of DC input voltage is converted into three-level AC voltage on the upper end and two-level AC voltage on the lower end through the inverter circuit, and the frequency and amplitude of the three-phase AC voltage can be adjusted. The three-phase E-type hybrid level double-output integrated converter can be widely applied to the double-motor driving application scene of one master and one slave, and has the advantages of reasonable structure, scientific modulation method, outstanding performance and the like.

The utility model belongs to motor manufacturing technical field especially relates to a rotor structure and motor, and the rotor structure includes rotor core, and the equidistribution of multiple magnetic poles has along its circumference, and each magnetic pole is provided with at least two layers of magnetic steel slot group, and each layer of magnetic steel slot group is C type structure, and each layer of magnetic steel slot group includes two separate magnetic steel slots about direct axis symmetry distribution, and the both ends of each magnetic steel slot are closed, magnetic steel is provided with multiple sections in each magnetic steel slot. The utility model is favorable for improving the magnetic field magnetic circuit of motor, reduces the harmonic distortion rate, thereby improves electromagnetic excitation, reduces motor torque ripple, realizes better motor NVH performance.

The invention relates to the technical field of alternating current power supply control, in particular to an improved load current feedforward control method and device for an alternating current power generation system and a medium, the method is suitable for a single-phase inverter system, and the method comprises the following steps: collecting inverter output voltage and load current; applying low-pass filtering to the load current to obtain filtered load current; adding the output of a voltage loop regulator and the filtered load current after necessary compensation in amplitude and phase to generate a current instruction; and driving an inverter to output according to the current instruction to realize adjustment and feed-forward compensation of the output voltage. According to the invention, the low-frequency output impedance in the inverter can be reduced, the harmonic distortion rate of the output voltage under the nonlinear load can be reduced, and the high-frequency-band waveform of the output impedance can be improved.

The invention discloses a grid-connected inverter stability control method based on an improved phase-locked loop, and belongs to the technical field of new energy grid-connected control, and the method comprises the steps: firstly building a grid-connected inverter impedance model, and revealing a mechanism that the phase-locked loop introduces negative damping and reduces stability margin under a weak power grid; based on an impedance model, a composite control strategy fusing dynamic feed-forward compensation and an improved Kalman observer is designed, the former actively counteracts the negative impedance effect of a phase-locked loop, and the latter improves dynamic response through state reconstruction and advanced prediction. Finally, an improved cascade delay signal elimination phase-locked loop with a selective conduction harmonic filtering function is provided, and the improved cascade delay signal elimination phase-locked loop is deeply integrated with the control strategy and a multi-harmonic feedback link, so that high-precision phase locking and active harmonic suppression are realized. According to the method, the operation stability, the dynamic performance and the electric energy quality of the grid-connected system under the conditions of high background harmonic waves and weak power grids are remarkably improved.