Page 84 - Hybrid-Renewable Energy Systems in Microgrids

68 Hybrid-Renewable Energy Systems in Microgrids

to multi pulse inverter. It only feels necessary for a simple switching strategy and
occupies less space.
Advantages

• Effortless packaging and simple storage
• Maintain common mode voltage, dv/dt stresses
• Low distortions in the input current waveform
• Operates at both fundamental and high switching frequencies
• Total harmonic distortion is very less in the output waveform without including filter circuit
Disadvantages

• Individual DC sources or capacitor stand in need for each module
• Have a need for a more convoluted controller due to the amount of capacitors

2.4 Comparison of different multilevel inverters

The comparison of different multilevel inverters is carried out on the following
paradigms:
• Number of semiconductor and circuit elements in each phase leg
• Number of DC bus capacitors considered
• Amplitude of harmonic factors
• Number of balancing capacitors in each phase leg
• Value of Total Harmonic Distortion (THD) in the output voltage waveform
• Regulate complexity for power switches and voltage unbalances
• Cost calculation correlated with power circuit (Table 4.2)

Table 4.2 The basic comparison based on the number of
components used

Diode Flying Cascaded
Sl No. Topology clamped capacitor H bridge
1. Power semiconductor 2(m−l) 2(m−l) 2(m−l)
switches
2. Clamping diodes per (m−l)(m−2) 0 0
phase
3. DC bus capacitors (m−1) (m−1) (m−l)/2
4. Balancing capacitors per 0 (m−l) 0
phase (m−2)/2
5. Voltage balancing Average High Very small
6. Applications Motor drive
system
STATCOM Motor drive system
STATCOM Motor drive system,
PV, fuel cells, battery
Systems