WASHINGTON — China’s biggest wind turbine company and two of its executives conspired with an employee of a Massachusetts wind company to steal the American firm’s software for controlling the flow of electricity, causing $800 million in damages, according to an indictment on Thursday.

The indictment by a federal grand jury in Madison, Wis., outlined actions that the Chinese firm, Sinovel, took against AMSC, formerly the American Superconductor Corporation, and represents the latest skirmish in a series of trade disputes between the United States and China involving renewable energy.

AMSC said the theft in 2011 led to the loss of 500 jobs and cited the damages as lost sales and trade secrets.

The two Chinese executives are in China, and the former employee, who was working for AMSC in Austria, has returned home to Serbia, according to John W. Vaudreuil, the United States attorney. He said that the United States did not have extradition treaties with either nation, but the accused could be arrested if they traveled to a country with which the United States does have an extradition treaty.