Patent ID: 8559193
Filing Date: 2013-10-15
Classification: H02M,Y02B

Abstract:
1. For a high-frequency-link converter having a high-frequency-link transformer coupled to a primary side converter and a secondary side converter, the secondary side converter comprising an ac/ac converter circuit for converting an ac input voltage to an ac output voltage, the ac input voltage varying between zero and a dc voltage, the ac/ac converter circuit including a leg comprising first and second arms, and each arm comprising first and second switches, a method for operating the ac/ac converter circuit, the method comprising, in sequence: a) during a time when the ac input voltage is zero, causing the first and second switches for both the first and second arms to be on; b) after a) and during a time when the ac input voltage is zero, causing a selected switch of the s second arm to be turned off; c) after b), causing the ac/ac converter circuit to receive the ac input voltage during a time when the ac input voltage transitions from zero to a dc level until a time during which the selected switch of the second arm blocks the ac input voltage, whereby a current direction through the second arm is reversed; d) after c), causing the ac/ac converter circuit to receive the ac input voltage until a time during which the primary-side converter attains a zero state and the ac input voltage approaches zero voltage, whereby current to the second arm is blocked; e) after d), causing the ac/ac converter circuit to receive the ac input voltage from a time during which the ac input voltage approaches zero until a time during which the ac input voltage is zero, whereby current flows through the second arm in the original direction; and f) after e), and while the ac input voltage is zero, causing the selected switch of the second arm to be turned on.