Onsemi, Sineng Electric Collaborate on Next-Gen Solar Inverter and Energy Storage Solutions

Onsemi has announced that Sineng Electric will be using the company’s EliteSiC MOSFET and IGBT technology in semi-custom power integration modules designed for the needs of Sineng’s emerging utility-scale solar inverter and 200kW energy storage system (ESS).   

Ground-mounted solar panel array. Image used courtesy of Sineng Electric

 

The power modules incorporate onsemi’s latest silicon carbide (SiC) and IGBT technologies and are developed through close collaboration between the two companies. The semi-custom modules are optimized for the high voltage power conversion needs of Sineng’s solar inverter and energy storage platforms.  

The most recent development work follows a long-term supply agreement signed by the two companies in 2022.  

 

Renewable Power Generation and Energy Storage

As the global economy electrifies, reducing its reliance on carbon energy sources, demand for renewable energy from solar, wind, hydro, and geothermal continues to grow. 

For utility-grade production, renewable plants are typically composed of the energy production source (solar, wind, etc.) and a long-duration energy storage capability that ensure a continuous electricity supply.

Efficient, high-voltage power conversion technologies are essential to operate these energy production and storage components.  

 

Solar plant deployment in India. Image used courtesy of Sineng Electric

 

Power Conversion for Solar Generation

Utility-grade solar power plants generate electricity from arrays of photovoltaic (PV) cells that convert light, or solar energy, to electricity. 

For use on the grid to support loads, the DC power from the PV arrays needs to be converted into usable three-phase AC via an inverter circuit that uses power switches and diodes to “chop,” filter, and condition the DC voltage into three-phase AC power.  

 

SP Series solar inverter circuit. Image used courtesy of Sineng

 

Energy Storage is Essential

Unlike on-demand energy sources powered by coal, oil, or even clean nuclear, electricity production from renewable sources like the sun or wind can be intermittent. However, the electricity demand is continuous, and customers expect electricity to be available when needed to power homes, factories, machinery, and buildings. 

To bridge this gap, renewable energy sources must be paired with long-duration energy storage solutions to supply power when renewable sources are unavailable. These storage solutions are often based on battery technologies (lithium-ion, flow, etc.) or mechanical solutions like pumped hydroelectric.

For battery energy storage systems, power conversion circuits (bi-directional inverters) are essential to provide the interface between the AC or DC power from renewables and the battery storage system. For an AC-coupled interface, a bi-directional AC/DC inverter circuit allows power transfer between the grid and storage battery to store surplus energy during high renewable production or to deliver energy during low production periods.   

Since PV cells generate DC voltages for solar plants, DC-coupled power conversion blocks can transfer energy to and from a storage battery without a direct connection to the grid.  

AC-coupled solar energy storage inverter. Image used courtesy of onsemi

 

SP Series Solar Inverter

Based out of Wuxi City, PRC, Sineng’s SP-275K-H1 solar inverter is a 1.2 x 0.73 x 0.35-meter utility-grade module that weighs about 130 kg. The unit accommodates a DC voltage input of up to 1500 VDC from the solar PV array and outputs up to 275 kW of utility grade, 50/60 Hz, 800 VAC power, with a conversion efficiency of about 99%. Each inverter can deliver close to 200 A of AC.

 

Sineng Energy Storage Solutions

Sineng offers a range of ESS solutions, including power generation, grid-side, user-side, and island microgrid solutions. These energy storage solutions serve as the power conversion interface between the grid or renewable power plant and the energy storage batteries.

 

EH Series 200 kW AC-coupled energy storage system. Image used courtesy of Sineng

 

Onsemi power conversion technology will be used in the latest 200 kW ESS offering, where the single-stage power modules with multi-level topology will help improve system efficiency and lower total cost of ownership.   

 

EH Series ESS functional circuit. Image used courtesy of Sineng Electric

 

Multi-Phase Power Modules

Advanced packaging capabilities allow multiple bridge converter phases to be incorporated into a single module, simplifying the system design process and saving space. 

Onsemi’s NXH020F120MNF1 power module incorporates four SiC MOSFET devices in a full bridge configuration. It is rated to up to 1200 V of withstand voltage, has a nominal on resistance of 20 mΩ, and can accommodate up to 50 A of continuous load current.

 

NXH020F120MNF1 full-bridge SIC power module. Image used courtesy of onsemi

 

NXH020F120MNF1 full-bridge schematic. Image used courtesy of onsemi