Abstract: A power conversion apparatus accurately estimates a main current of a power device using observation of a sense current. The power conversion apparatus includes: an inverter circuit including a device having a main element and a sense element; a temporary-main-current estimator estimates a current flowing through the main element, from a sense current flowing through the sense element, as a temporary main current; a temperature-difference estimator configured to estimate a temperature difference between the main element and the sense element based on a gate drive signal for the main element and the temporary main current; a main-current corrector corrects the temporary main current using the estimated temperature difference and a temperature characteristic of on-resistance of the main element and output the corrected temporary main current as a corrected main current; and an inverter control circuit configured to output the gate drive signal based on the corrected main current.

Abstract: Provided is a novel power conversion device that enables estimation of a temperature of a power device without using a temperature sensing diode and can accurately estimate a temperature and a current of a current sensing element that observes a main current. A measurement voltage (Vref) is applied between source terminals (31s and 49s) of a main control element 31 and a current sensing element 49 in a state in which the main control element 31 and the current sensing element 49 are turned off, and a temperature of a power device 30 is estimated from a current (Ib) flowing between the source terminals (31s and 49s) of the main control element 31 and the current sensing element 49 at the time of the application by using the fact that a resistance value of a semiconductor substrate between the source terminals of the main control element 31 and the current sensing element 49 has temperature dependency.

Abstract: A semiconductor laser apparatus having an optical waveguide made of a semiconductor crystal, an optical cavity made of a mirror facet for reflecting light into the optical waveguide, and an optical gain region occupying at least part of the optical waveguide for generating an optical gain when powered. The optical gain region exists over a linear portion of the optical waveguide. The remaining portion of the optical waveguide is at least partially bent in structure.