Modeling and simulation of multi‐scale transients for PMSG‐based wind power systems

Abstract

In a wind energy conversion system (WECS), multiple-time-scale transients that cover a wide frequency range from low-frequency transient stability up to high-frequency switching events are observed. This paper presents a methodology of modeling diverse transients for a permanent magnet synchronous generator (PMSG)-based WECS within the same study. Multiple physical areas of the PMSG-based WECS are given depending on the appearance of carriers contained in the considered waveforms. In order to eliminate different carrier frequencies, the PMSG and generator-side voltage source converter (VSC) are modeled in the dq0-reference frame. On the other hand, the grid-side VSC and utility grid are dealt with in the multi-scale model of the network in which the shift frequency is available. The switching-function and average-value models of the VSC are selected depending on the carrier shifted. In addition, interface between the control and electrical subsystems is redesigned to offset the computation error caused by one time-step delay. Two test cases are performed to study the wind power fluctuations and faults ride-through. The results show that the proposed multi-scale model is able to simulate slow-changing dynamic responses up to high-frequency transients accurately while decreasing the simulation burden. In comparison with the results obtained from the EMTP (electromagnetic transients program) type simulators, the effectiveness and accuracy of the multi-scale model are verified.

Progress on the Development of a Holistic Coupled Model of Dynamics for Offshore Wind Farms: Phase II — Study on a Data-Driven Based Reduced-Order Model for a Single Wind Turbine

“…The influence of the tower on the wind local to the blades is considered using an analytical potential-flow theory, but wind loading on the tower is calculated quasi-statically [16]. As for the electric dynamics, whose topology has already been introduced in Figure 1, the PMSG has been modelled by the well-known qd model [4,19] and operated, together with its VSC, by vector control means. The network link dynamics have been modelled in the dq frame.…”

“…On the other hand, detailed models of the electrical components, including the generator, converter and AC/DC link, etc. have been widely developed in the past few decades.Analogously, in such models, the non-linear dynamics of the wind turbine are substantially simplified down to an analytical function of blade pitch angle, wind speed and wind turbine angular speed [4,5].…”

Study of double rotor speed-regulating wind power generation system

“…When i d = 0, the torque equation of the double rotor speed-regulating generator is shown in formula (10) according to the formula (7).…”

“…The formula (10) shows that the torque of the double rotor speed-regulating generator is only related to the q axis current. Therefore, controlling the q axis current can control the torque of the double rotor speed-regulating generator and then control the outer rotor to track the maximum power point.…”

“…Specifically, the harmonic frequency of the stator output current is stable and easy to control [10]. Besides, the generator and the power grid are isolated by the full power converter, so there is no current impact and the power grid adaptability is stronger [11].…”