US clean energy firm AMSC sues China's Sinovel over intellectual property theft

US-based clean energy technology company AMSC has sued its largest customer, Chinese wind turbine maker Sinovel, in Beijing's High Court for $400 million over alleged intellectual property theft.

The latest suit is one of five cases being pursued by AMSC against Sinovel, the world's second-biggest wind turbine manufacturer over theft of wind-turbine electronics software code.

Formerly known as American Superconductor Corp, Boston-based AMSC alleges that Sinovel illegally obtained and used its intellectual property to upgrade its 1.5 megawatt wind turbines in the field to meet proposed Chinese grid codes and to potentially allow for the use of core electrical components from other manufacturers.

AMSC has been supplying core components, software that controls the productivity and quality of wind power in turbines, and licensing of turbine designs to Sinovel since 2006.

AMSC got suspicious in April this year when Sinovel rejected a large shipment of control components and later drastically reduced business with AMSC.

Until May, nearly 80 per cent of AMSC's revenue came from Sinovel.