A new approach for load flow calculation in AC/DC distribution networks considering the control strategies of different converters

et al. 2017

Energies

An integral plus resonant sliding mode direct power control (IRSMC DPC) strategy for voltage source converter high voltage direct current (VSC-HVDC) systems under unbalanced grid voltage conditions is proposed in this paper. Through detailed instantaneous power flow analysis, a generalized power compensation method, by which the ratio between the amplitude of active and reactive power ripples can be controlled continuously, is obtained. This enables the system to provide flexible power control, so that the desired performance of the system on both the ac and dc sides can be attained under different operating conditions. When the grid voltage is unbalanced, one or both of the active and reactive power terms contain ripples, oscillating at twice the grid frequency, to obtain non-distorted ac current. A power controller consisting of the proportional, integral and resonant control laws is designed using the sliding mode control approach, to achieve accurate power control objective. Simulation studies on a two-terminal VSC-HVDC system using MATLAB/SIMULINK (R2013b, Mathworks, Natick, MA, USA) are conducted to verify the effectiveness of the IRSMC DPC strategy. The results show that this strategy ensures satisfactory performance of the system over a wide range of operating conditions.

“…Energies 2017, 10, 1528 5 of 17 Substituting Equations (6) and (7) into Equation (3), and through some mathematical manipulations, we have:…”

Section: Mathematical Model Of the Converter Stationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Integral Plus Resonant Sliding Mode Direct Power Control for VSC-HVDC Systems under Unbalanced Grid Voltage Conditions

Yang

et al. 2017

Energies

“…Traditionally, the topology of the AC/DC converter is usually reported to select two-and three-level unidirectional converters to save the cost. 11,12 However, the total harmonic distortion (THD) of the AC current is increased and thus the power quality is decreased. Therefore, the VIENNA-based rectifier topology is emerging and becomes popular due to the advantages of simple structure, low input current THD, low voltage stress, etc.…”

Section: Introductionmentioning

confidence: 99%

Proportional integral resonance based sliding mode control of VIENNA rectifier for charging station of tramcar under unbalanced power supply

Zhou

Int Trans Electr Energ Syst

et al. 2020

In order to eliminate the ripple of the active power and suppress the negative sequence current produced during the charging process of the tramcar under both balanced and unbalanced power supply conditions, a novel proportional integral resonance based sliding mode (PIRSM) control scheme is proposed in this article for the VIENNA rectifier of the charging station. After deriving the power model in the stationary coordinate system, the mathematical model of the VIENNA rectifier under unbalanced power supply is built. Subsequently, a unified control objective is introduced to make the proposed scheme available for different operating condition without changing the algorithm. Moreover, the resonance control and sliding mode control are combined together to construct the sliding mode surface, and the control law are derived based on the stability requirement to make the system approach its desired operating point with expected trajectory. Experimental results show that compared to the conventional PI control, the proposed control can ensure the better power tracking performances and higher power quality under different power supply conditions.

“…The VSC‐MVDC system can provide flexible power control and facilitate power grid interconnection and the integration of distributed generations (DG). It is expected to solve problems such as power supply capability insufficiency, difficulty in the integration of DG, and powering MVDC loads, which is faced by ac distribution network . However, operating conditions of the grid often change drastically.…”

Section: Introductionmentioning

confidence: 99%

Adaptive integral sliding mode direct power control for VSC-MVDC system converter stations

Yang

Int Trans Electr Energ Syst

et al. 2018

An adaptive integral sliding mode direct power control (AISMC DPC) strategy for voltage source converter medium voltage direct current (VSC-MVDC) system converter stations (CS) is proposed in this paper. For high power VSC-based applications, the time delays in the control loops have significant adverse impacts on system performance and robustness. Aiming at these problems, an integral sliding mode control (ISMC) based DPC controller, consisting of the proportional and the integral control laws, is firstly designed for the CS to realize accurate power regulation objective. Then, based on the ISMC DPC controller, an ac line parameter adaptive scheme with error compensation, i.e., the AISMC DPC strategy is proposed, to improve the robustness and the transient performance of the system. Simulation studies on a 2-terminal VSC-MVDC system are conducted to verify the effectiveness of the proposed AISMC DPC strategy. The results show that the strategy provides satisfactory performance of the system over wide range of operating conditions.