7results about How to "Avoid harmonics" patented technology

The invention discloses a through traction power supply system based on two-phase-single-phase isolation and non-isolation hybrid topologies, and belongs to the technical field of power electronic transformers, the through traction power supply system comprises two single-phase isolation and non-isolation hybrid topologies, each single-phase isolation and non-isolation hybrid topologies comprises an isolation unit and a non-isolation unit which are cascaded, each isolation unit comprises one or more cascaded isolation modules, the isolation module comprises a first rectifier, an isolation type power electronic transformer and a first inverter which are in cascade connection in sequence; the non-isolation unit comprises one or more cascaded non-isolation modules, and each non-isolation module comprises a second rectifier and a second inverter which are cascaded in sequence. Compared with a system adopting transformer isolation, an industrial frequency transformer and part of high-frequency isolation transformers are omitted, a short-circuit path can be blocked based on the isolation module, the topological volume is effectively reduced, the cost is reduced, and compared with a completely non-isolated system, the available vector plane is widened, and the safety and reliability of the system are high.

The suppression assembly comprises a mutual inductor shell, a magnetic screen mutual inductor shell in the mutual inductor shell is structurally designed to comprise an electromagnetic wave reflecting layer and an electromagnetic wave absorbing layer, one side of the mutual inductor shell is provided with an arc-extinguishing and resonance-eliminating mechanism, the arc-extinguishing and resonance-eliminating mechanism comprises a resistor resonance-eliminating piece, a capacitor and an arc-extinguishing cover, and the resistor resonance-eliminating piece is connected with the capacitor and the arc-extinguishing cover. The arc extinguishing chambers are arranged on the periphery of the primary wiring terminal in the mutual inductor shell; according to the suppression assembly for the PT open delta winding, resonance is suppressed through the resistor resonance elimination piece to generate overvoltage, a voltage transformer is prevented from being burnt out, the arc extinguishing cover is arranged on the periphery of the primary wiring terminal in the transformer shell and used for attracting the overvoltage generated by the primary wiring terminal, and the voltage transformer is prevented from being burnt out. And a large amount of energy generated by overvoltage is transmitted and stored into the capacitor through the connecting seat, the cross block, the fixed block I, the lifting telescopic rod and the telescopic guide cylinder which are connected, so that the overvoltage is absorbed, and the voltage transformer is prevented from being burnt due to long-time overvoltage.

The invention discloses a frequency converter motor system and a control method of the frequency converter motor system, relates to the technical field of air conditioners, and aims to solve the problem that harmonic waves generated by power grid side current in an electrolytic capacitor-free frequency converter driving system reduce the power grid side electric energy quality in the electrolytic capacitor-free frequency converter driving system. The method comprises the following steps: acquiring three-phase current of the permanent magnet synchronous motor and three-phase duty ratio of the inverter; and obtaining a reconstructed inductive current of the inductor according to the three-phase current and the three-phase duty ratio. And obtaining the inductive current of at least one frequency in the reconstructed inductive current. And obtaining a first compensation voltage of the permanent magnet synchronous motor according to the inductive current of the at least one frequency, the first compensation voltage being used for adjusting an input voltage of the permanent magnet synchronous motor.

The present invention discloses a novel dielectric filter coupling structure, comprising a dielectric filter body, a first blind hole and a second blind hole, wherein the first blind hole and the second blind hole are arranged on the same side of the dielectric filter body, the first blind hole and the second blind hole and the dielectric on the dielectric filter body form two dielectric resonators, a negative coupling hole is arranged between the two dielectric resonators, the openings of the negative coupling hole and the first debugging hole and the second debugging hole are located on the same surface of the dielectric filter body, one end of the negative coupling hole passes through the dielectric filter body, and the other end is a closed end, a boss is arranged in the negative coupling hole, the boss is an integral structure with the dielectric filter body, and a continuous conductive layer is arranged on the inner wall of the negative coupling hole and the outer wall of the boss. The present invention can realize the control of the far-end parasitic passband frequency while realizing capacitive coupling.

The application provides a dynamic equalization method and circuit, which comprises the following steps: calculating a maximum gain coefficient and a minimum gain coefficient according to an input signal and preset processing parameters; multiplying the filtered input signal and one of the maximum gain coefficient and the minimum gain coefficient to obtain a first output signal; multiplying the input signal directly or after filtering or delaying and the other of the maximum gain coefficient and the minimum gain coefficient to obtain a second output signal; and superimposing the first output signal and the second output signal to obtain a final output signal; and adjusting the proportional relationship between the two input signals to achieve the purpose of adjusting the final output signal in real time. This method simplifies the required calculation amount and storage space of the dynamic filter, avoids the problem of harmonic and noise caused by the sudden change of the filter coefficient, and is effective in optimizing the calculation amount.

The invention discloses a pre-synchronization method, a pre-synchronization device and a medium, relates to the technical field of grid-connected converter control, and provides the pre-synchronization method for solving the problems of relatively high threshold and insufficient efficiency of parameter pre-synchronization through a phase-locked loop method at present. Synchronization of amplitude, frequency and phase can be completed only by processing alternating current bus voltage and inverter output voltage through a simple mathematical method. Parameter difference before grid connection of a grid-forming system can be eliminated without depending on a phase-locked loop or a control link needing parameter setting, and the purposes of suppressing grid-connected impact current, avoiding current distortion and harmonic problems and ensuring smooth transition of grid-connected and off-grid mode switching are achieved. Therefore, compared with a common pre-synchronization scheme based on a phase-locked loop, the method occupies less computing resources, has a lower threshold and is easy to realize in an engineering manner. And moreover, the synchronization efficiency is higher, and the switching efficiency of the grid-connected and off-grid modes of the network construction type system is improved.

The utility model discloses a test module for a high-power tuning antenna switch. The test module comprises a transmitting link (101) and a receiving link (102), each of the transmitting link (101) and the receiving link (102) is provided with a switch array. According to the test module for the high-power tuning antenna switch disclosed by the utility model, through the switch array, the normalization test of low-power signals and high-power signals is realized, and the test efficiency of test equipment is greatly improved.