University of South Wales Master of Sciences Thesis
Power Electronics and control Topologies for BES
tải về 6.62 Mb. Chế độ xem pdf
|
| 2.6.3. Power Electronics and control Topologies for BES
The power electronics topologies for the battery energy storage systems can be of different types based on the number of cascaded stages in the conversion systems, types of converters, presence of galvanic isolation, and utility connection. The most fundamental topology for utility connection of the BESS is the single-stage, self- commutated voltage-source inverter as shown in Figure 49. While the DC output of the battery system is connected across a filter capacitor, the capacitor itself is used to limit the harmonic currents in the battery. The output of the capacitor connects to a voltage-source inverter (VSI) (Ponnaluri et al. 2005; Leung and Sutanto 2000). Depending on the utility connection, the inverter can be single-phase or Standalone hybrid generation system for the remote area of Thar, Pakistan three-phase. The output of the inverter is then connected to a low-pass filter to prevent high-frequency harmonics injected into the AC system. A synthesized AC-output voltage is produced by appropriately controlling the switches and consists of a controlled series of positive and negative pulses that correspond to the positive and negative half cycles of a sinusoid. Fig. 2.31 Single-stage power electronics topologies with (a) Single-phase inverter; (b) Three-phase inverter The most common two-stage topology for the BESS consists of a DC-AC micro-grid-connected voltage source PWM inverter with a bidirectional DC-DC converter. The DC-AC full-bridge inverter controls the micro-grid current by means of pulse width modulation (PWM), known as a “bang-bang” operation. A simple design for a two-stage power electronics topology, as shown in Figure 50, incorporates a full-bridge DC-DC converter that can operate with any voltage and current polarity. The voltage polarity and amplitude can be set irrespective of the current direction (Mohan et al. 2003). tải về 6.62 Mb. Chia sẻ với bạn bè của bạn:
|