The acquisition of Camarillo solar equipment manufacturer Power-One Inc. by a Swiss company has been approved by its stockholders, the company said Tuesday.

Swiss engineering company ABB agreed to buy Power-One Inc. for $1 billion in April. The Zurich company offered Power-One shareholders $6.35 a share, a 57 cent premium over its stock price at the time.

Power-One said that about 98 percent of the shares voting at Tuesday’s meeting voted in favor of the merger, which represented more than 73 percent of the total common shares outstanding.

ABB designs and manufactures robotics used in solar and automation technology, and already makes its own version of Power-One’s primary product, an inverter that converts solar power from direct current to alternating current that is usable by customers.

Power-One reported a net profit of $120 million last year, despite a $17.1 million loss in the fourth quarter, which it blamed on weak European sales. It is the second-largest inverter manufacturer in the world; German firm SMA Solar Technology is the largest.

The transaction has already received the required antitrust approvals and should be completed by the end of the week.

Shares of Power-One on Tuesday closed up a cent, or less than 1 percent, to $6.34 on the Nasdaq.