Hefei University of Technology

Changxin Memory Technologies, Inc.

Xing Zhang

Yang Wang

Ming Li

Zixuan Guo

Jilei Wang

Hailong Pan

Qian Gao

Feng Han

Xiangdui Zhan

Xinxin Fu

Enjun Liu

Xing Wang

Yongtao Mao

Yu Xiao

Congjun Wu

Zhen Xie

Shaolong Chen

Xiaofang Zhou

A passivity-based dual-mode integrated control method for a grid-connected inverter (GCI) is provided. In view of the insufficient robustness of the conventional single-mode GCI in a high-impedance and low-inertia weak grid, and the problem of wideband oscillation of the grid voltage and grid current or even system instability in nonlinear application scenarios such as grid structure/parameter variation, and plug-and-play of the inverter, the dual-mode integrated control method performs modeling on the GCI based on a port-controlled Hamiltonian (PCH) model, thereby obtaining integrated control with a weighted passivity-based feedback control law for the GCI based on a grid-following (GFL) mode and a grid-forming (GFM) mode. Based on the dual-mode integrated control method, the stable operation of the GCI in severe grid conditions with large fluctuation of the impedance, and desirable robustness of the GCI in nonlinear working scenarios can be ensured.

Passivity-based dual-mode integrated control method for grid-connected inverter

A method for hybrid control of grid-connected inverter based on time sharing of a voltage source and a current source including at least one control process, each control process including N+M control cycles. N may be a number of control cycles of a grid-connected inverter operating in a voltage source mode, M may be a number of control cycles of the grid-connected inverter operating in a current source mode. The control cycles of the grid-connected inverter operating in a voltage source mode and a current source mode may switch by counting. Aiming at a problem of being difficult to realize stable operation under large fluctuations in SCR, the present disclosure realizes a time-sharing control of the voltage source mode and the current source mode through a control algorithm, hybrids features of both mode, improves the stability of the grid-connected inverter, and realizes a stable operation under large fluctuations in SCR.

Method for hybrid control of grid-connected inverter based on time sharing of a voltage source and a current source

A multi-mode control method for a grid-connected inverter includes: continuously calculating an effective value Vof a voltage harmonic of a filtering capacitor; perturbing a control parameter to excite the voltage harmonic of the filtering capacitor; estimating a grid condition based on the perturbed control parameter and the effective value Vof the voltage harmonic of the filtering capacitor; and switching a control mode of the grid-connected inverter based on the estimated grid condition. The multi-mode control method provides a grid condition detection method, which excites the voltage harmonic by perturbing the control parameter and determines the grid condition by the relationship between the control parameter and the effective value of the voltage harmonic. The multi-mode control method eliminates the need for additional grid impedance measurement equipment, and adapts to complex grid conditions with significant changes in the system short-circuit ratio (SCR) and the system series compensation degree.

Multi-mode control method for grid-connected inverter

A dual-mode combined control method for a multi-inverter system based on a double split transformer is provided. For an extremely-weak grid, the method provides the dual-mode combined control method for a multi-inverter system based on a double split transformer. According to the method, the equivalent grid impedance at a point of common coupling (PCC) of one grid-connected inverter (GCI) in the multi-inverter system based on the double split transformer is obtained with a grid impedance identification algorithm, and the system sequentially operates in a full current source mode, a hybrid mode, and a full voltage source mode according to a gradually increasing equivalent grid impedance, thereby effectively improving the stability of the multi-inverter system based on the double split transformer during variation of the strength of the grid. The method ensures that the system can still operate stably in the extremely-weak grid.

Dual-mode combined control method for multi-inverter system based on double split transformer

A stability control method for a virtual synchronous generator (VSG) in a strong grid based on an inductance-current differential feedback is provided. A grid-connected topological structure of a VSG using the control method includes a direct-current (DC)-side voltage source, a three-phase inverter, a three-phase grid impedance and a three-phase grid. By controlling the VSG and controlling the inductance-current differential feedback, the method suppresses the oscillation of the output power from the VSG in the strong grid and implements the stable operation of an inner-loop-free VSG in the strong grid, without adding the physical inductance, increasing the cost of the filter and additionally providing a grid-side current sensor.

Stability control method for virtual synchronous generator in strong grid based on inductance-current differential feedback

Embodiments of the present disclosure provide a device for adjusting a wafer, a reaction chamber, and a method for adjusting a wafer. The device for adjusting a wafer includes: a lifting module, the lifting module including a first carrier surface configured to carry a wafer, and the first carrier surface ascending to a preset highest position or descending to a preset lowest position relative to a reference surface; a carrier module, the carrier module including a second carrier surface, a position of the second carrier surface being higher than the preset lowest position and being lower than the preset highest position, and the second carrier surface being configured to receive and carry the wafer carried on the first carrier surface; and a suction module, the suction module including a first suction opening facing the wafer and surrounded by the second carrier surface.

Device for adjusting wafer, reaction chamber, and method for adjusting wafer

In a control method for overlay accuracy, whether a similar layer of a present layer exists is determined first, where both the present layer and the similar layer are aligned relative to a same reference layer, and overlay accuracy requirements of both the present layer and the similar layer are relative to the reference layer; if so, an overlay error compensation value of a present batch of wafers at the present layer is determined according to an overlay error value of the present batch of wafers at the similar layer and/or an overlay error value of a previous batch of wafers at the similar layer; and a photoetching process is performed on the present layer of the present batch of wafers by means of the overlay error compensation value of the present batch of wafers at the present layer.

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Hefei, China

Xing Zhang