New high power, high performance power converter systems

Abstract

A new, high performance, low cost power converter system architecture is proposed. The system consists of a main converter and a multi-functional load conditioner. The main converter deals with most of the power flow running at a lowswitching frequency. The load conditioner is designed at a much lower power level running at a high-switching frequency. The load conditioner can (1) act like a current source and inject harmonic currents required by the load; (2) act like an active resistor to provide damping to the main converter; and (3) for three-phase inverters, decouple the coupling sources in the main inverter to make the control loop design for the main inverter much easier. The concept has been proved by simulation and experimental results on a 150 kW high performance three-phase utility power supply prototype.The proposed system configuration can be used in high power DCDC converters, inverters, PFC and UPS applications.

Measurement of the Loop Gain Frequency Response of Digitally Controlled Power Converters

“…Due to the fact that the sampling rate is generally low in high power conversion applications, interferences caused by the power semiconductors switching could be aliased into the low-frequency band as a result of sampling, therefore an antialiasing filter H AA (s) must be used [21]. Typical filters includes 4 th order filters based on the cascade connection of two 2 nd order filter as the one shown in (6), where the cut-off frequency, ω c , is designed to be less than half of the sampling frequency and Q is chosen to obtain a butterworth response, hence ω c ≤4π/T s and Q=0.7, where T s is the sampling period.…”

“…t is well known that the analysis of the open loop gain frequency response of a closed loop controller allows the designers to study the dynamic response as well as the stability of the system [1,2]; for that reason, the loop gain is usually measured in the design procedure of the controllers, obtaining Nyquist plots [3,4] or their equivalent Bode plots [5][6][7][8][9]. Both of them allow measuring the phase and gain margins, which in turn gives information about the bandwidth and the stability of the process, among other important parameters.…”

Control strategy and application of power converter system in battery energy storage system

“…Therein, PCS is a bi-directed AC-DC converter, which is the key factor of BESS to meet the variable operation demands [4]- [6].…”