Phase locked-loop with decaying DC transient removal for three-phase grids

Self Cite

The voltage source converter (VSC) based high-voltage DC (HVDC) transmission system usually adopts damping and inertia control to quickly and independently adjust the active- and reactive- power, to improve the frequency stability and suppress the electromechanical oscillations of the power grid. This paper first analyzes the effect of the proportional-derivative (PD) controller parameter on the HVDC output power. The study shows that when the proportional-derivative controller parameter is increased to the limit value, HVDC will operate in the rapid power compensation (RPC) mode. Namely, according to the positive or negative polarities of the rotor speed deviation and the grid frequency deviation, the active- and reactive- power limits are used as the reference to rapidly control the output power, thereby minimizing the system’s unbalanced power, the rotor oscillation, and the frequency fluctuation. To this end, this paper proposes a coordinated active-/reactive- power control strategy for the VSC-HVDC system based on the RPC mode to suppress the grid electromechanical and frequency oscillations. The RPC mode enables HVDC to quickly release/absorb power, to compensate for system’s required power shortage or suppress excess power. When the speed deviation, the frequency deviation, and their rates of change meet the requirements, the damping control is used to make HVDC exit the RPC mode and further enhance the ability of the VSC-HVDC system. Simulation results prove the effectiveness of the proposed power optimization control strategy.

Section: Vsc-hvdc System Structure and Its Control Strategymentioning

confidence: 99%

Power optimization control of VSC-HVDC system for electromechanical oscillation suppression and grid frequency control

Yang

et al. 2022

Self Cite

“…The generating capacity of hydropower, wind power, and solar power has increased by 20.3%, 7.8%, and 13.5% from the last year, respectively. Largescale wind power and PV on-grid has posed a huge challenge to the safety and reliability of power system (Lei et al, 2022;Liu et al, 2022). From the perspective of system operation, installing energy storage not only mitigates PV power fluctuation but also realizes real-time scheduling of tracking power and enhance the grid's ability to consume new energy (Wang et al, 2019); in addition, the joint operation of PV power generation and energy storage can play the role of peak shaving and valley filling and also participate in auxiliary services (Motalleb et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

An optimal energy storage system sizing determination for improving the utilization and forecasting accuracy of photovoltaic (PV) power stations

Li²,

Yan³

et al. 2023

As a new type of flexible regulation resource, energy storage systems not only smooth out the fluctuation of new energy generation but also track the generation scheduling combined with new energy power to enhance the reliability of new energy system operations. In recent years, installing energy storage for new on-grid energy power stations has become a basic requirement in China, but there is still a lack of relevant assessment strategies and techno-economic evaluation of the size determination of energy storage systems from the perspective of new energy power stations. Therefore, this paper starts from summarizing the role and configuration method of energy storage in new energy power stations and then proposes multidimensional evaluation indicators, including the solar curtailment rate, forecasting accuracy, and economics, which are taken as the optimization targets for configuring energy storage systems in PV power stations. Lastly, taking the operational data of a 4000 MWPV plant in Belgium, for example, we develop six scenarios with different ratios of energy storage capacity and further explore the impact of energy storage size on the solar curtailment rate, PV curtailment power, and economics. The method proposed in this paper is effective for the performance evaluation of large PV power stations with annual operating data, realizes the automatic analysis on the optimal size determination of energy storage system for PV power stations, and verifies the rationality of the principle for configuring energy storage for PV power stations in some regions of China.

“…In addition, ADM control can also be applied to other DC converters, such as double-active half-bridge and three-phase double-active bridge (Kim et al, 2009;Ngo et al, 2012;Chakraborty and Chattopadhyay, 2018;Huang et al, 2019). However, the ADM control contains only two degrees of freedom, which limits the flexibility of the control (Xiong et al, 2021;Zhou et al, 2021;Liu et al, 2022b).…”

Section: Introductionmentioning

confidence: 99%

Research on optimum extended phase-shift control with minimum peak-to-peak current of DAB converter applied to small DC power grid

Shi¹,

Du²,

Xia

et al. 2023

The Dual Active Bridge (DAB) DC-DC converter has the ability of bidirectional power transmission and the modulation scheme that is easy to implement, which can ensure the efficient transmission of energy in the system. Therefore, it is often used in various scenarios of small DC grid, such as energy storage, photovoltaic system, electric vehicle charging and so on. The main methods to improve the efficiency of dual active bridge include reducing the effective value of current and widening the soft switching area. Based on the above idea, an optimized extended phase-shift (EPS) modulation strategy is proposed in this paper. The modulation strategy achieves the goal of reducing the effective value of the current through the constraint optimization of the corresponding variables, and then improves the efficiency of the converter. In this paper, the working principles of several typical modulation strategies are introduced in detail, and then the power characteristics and soft-switching characteristics of the new method and other commonly used modulation schemes are analyzed and compared. Finally, the effectiveness of the optimization method for extended phase-shift modulation strategy is verified by the dual active bridge experimental prototype.