4results about How to "Reduce peak current" patented technology

The invention discloses a resonant dual-active bridge converter and a control method, and the converter comprises a primary full-bridge circuit, a secondary full-bridge or half-bridge circuit, a transformer, and an LC resonant network composed of a resonant inductor and a resonant capacitor which are connected in series. The control method comprises the following steps: acquiring parameters of an input voltage V1, an output voltage V2, a transmission power P, a transformer turn ratio N, a resonant inductance Lm and a resonant capacitance Cr of the converter; and calculating a primary fundamental wave equivalent voltage and a secondary fundamental wave equivalent voltage, and calculating an inner phase shift angle alpha between a first bridge arm and a second bridge arm in the primary full-bridge circuit through the primary fundamental wave equivalent voltage and the secondary fundamental wave equivalent voltage. The LLC converter has the beneficial effects that the inherent defects that the gain range of a traditional LLC converter is narrow (generally only 0.8-1.2) and the circulating current is sharply increased and the efficiency is sharply reduced when the voltage is seriously mismatched in the traditional phase-shifting DAB are fundamentally overcome.

The application discloses a kind of based on single-stage grid-connected micro-reverse soft switching online real-time monitoring and closed-loop maintenance control method and system, mainly solve the problem of existing zero-voltage opening / non-zero voltage opening boundary difficult to judge and light load zero-crossing region loss soft switch leads to hard opening, its scheme includes: sampling the real-time state variable operated in single-stage grid-connected micro-reverse circuit, based on the sampled photovoltaic side voltage, photovoltaic side current, grid side voltage and grid side phase, respectively calculate internal and external moving phasor;Custom dead time and target level, according to the dead time and the sampled bridge arm commutation current, bridge arm commutation voltage and switching node voltage judge the soft switching state when commutation event k time;Based on the soft switching state, calculate the corrected internal and external moving phasor, output the driving signal of switch tube, to realize the soft switching online real-time monitoring and closed-loop maintenance of single-stage grid-connected micro-reverse.The application can improve the robustness of soft switching implementation, reduce the risk of hard opening, and can be used for soft switching control and energy transmission of single-stage grid-connected micro-reverse.

The application discloses a beam-type pumping unit front balance and accident protection device, and relates to the field of pumping units, which comprises a support, a beam, a hydraulic cylinder, a balance energy accumulator and a high-pressure hose, the beam is movably hinged at the top end of the support, one end of the hydraulic cylinder is hingedly connected with the forearm of the beam, the other end of the hydraulic cylinder is hingedly connected with the middle upper part of the support, the end of the hydraulic cylinder close to the support is provided with a self-locking valve, the balance energy accumulator is connected to the support and located on the side away from the hydraulic cylinder, and the balance energy accumulator and the self-locking valve are connected together through the high-pressure hose. The application solves the problem of poor torque balance of the four-link mechanism of the beam-type pumping unit, reduces the current peak value of the motor, saves the energy of crude oil exploitation, realizes the effect of secondary self-locking protection of the beam-type pumping unit during shutdown, avoids the safety risk of manual locking brake failure, and effectively improves the safety performance of the pumping unit.

The application provides a semiconductor device structure and a preparation method thereof. The semiconductor device structure comprises a back layer of a first conductive type which is composed of a buffer layer of the first conductive type and a freewheeling heavy doped region of the first conductive type under the deep trench field plate, a trench gate and a deep trench field plate which penetrate a body region of a second conductive type and extend into a substrate layer of the first conductive type; and the trench gate which also penetrates the heavy doped region of the first conductive type has a depth smaller than that of the deep trench field plate. The deep trench field plate which is short-circuited with the emitter and arranged on both sides of the trench gate can accumulate a large number of holes when the deep trench field plate is turned on, so that the on-state voltage drop is reduced. Meanwhile, the deep trench field plate optimizes the compromise relationship between the FRD breakdown voltage and the on-state voltage in the RC-IGBT with a vertical electric field distribution, so that the working loss of the RC-IGBT in the freewheeling state is reduced. In addition, the deep trench field plate can quickly extract the carriers in the depletion layer in the freewheeling state, so that the current released in the reverse recovery is reduced, and the peak current in the reverse recovery is reduced.