Inverters

Researchers from the U.S. National Renewable Energy Laboratory have developed a tool to balance customer curtailment and grid stability. The “Precise” tool for utilities provides unique inverter settings tailored to each customer, with minimal investment and labor for companies that use it.

A 120 MW solar plant located in a fishery near Cixi, in the Chinese province of Zhejiang, was recently completed. The plant, which has secured a tariff of RMB0.95 ($0.12)/kWh, is the second phase of a 320 MW project owned by Chinese developer Hangzhou Fengling.

The U.S. conglomerate plans to deploy and test new controls with its commercial PV LV5 inverter platform. It aims to develop “grid-forming” controls to allow wind and solar inverters to form voltage and frequency levels like traditional generators. The company wants to improve coordination and synchronization among multiple grid-forming resources, and is working on smart PV reserve controls to improve the transient stability of systems with high renewables penetration.

The so-called Optiverter is an all-in-one residential solution developed by startup Ubik Solutions and researchers from Estonia’s TalTech Power Electronics Research Group. The developers claim that the new solution can provide 30% more power than traditional microinverters under partially shaded conditions.

According to a Norwegian group of researchers, the reactive power capability of three-phase voltage source inverters can help to reduce problems caused by the intermittent nature of solar power on distribution networks. The scientists claim they are preferable to expensive grid infrastructure such as under-load tap changing transformers, step voltage regulators, and fixed and switchable capacitors. The group has developed a system model featuring a 7.63 kW PV array module, a three-phase voltage source inverter with 9.5 kVA of capacity, a boost converter, a three-phase dynamic load, and a utility grid.

Researchers in Pakistan have evaluated the impact of shading on inverter set-ups to assess PV system performance. Tests were conducted on a 51 kW system featuring SMA inverter topologies but the researchers say the findings could be applied to products from other manufacturers. The results showed the number of maximum power point trackers is important but levelized cost of energy calculations are also crucial to selecting the right inverter configuration.

Italian inverter maker Fimer has completed its purchase of ABB’s manufacturing and R&D sites in Finland, India and Italy, along with 800 employees in 26 countries. Fimer said the combined business will ship more than 7 GW of inverters this year.

The inverters of the TL-XH series have efficiencies ranging from 98.2% to 98.4%. The 10.8 kg devices are compatible with double-glass modules and higher yields, the manufacturer claims.

Scientists in India have tested a new inverter topology with a single-phase, induction-motor water pump. The seven-level inverter, with five power semiconductor switches, is said to be particularly efficient at reducing switching losses thanks to a pulse width modulation technique.

Japanese researchers have investigated the effectiveness of SiC devices in sub-kilowatt applications. A 790g device was tested in a mini PV generator system which included a battery and maximum power point tracker circuit in the same housing. Compared to traditional mini inverters the SiC device showed 3% higher efficiency.