**Compact Single-Stage Micro-Inverter with Advanced Control Schemes for Photovoltaic Systems**

#### **Yoon-Geol Choi 1, Hyeon-Seok Lee 1, Bongkoo Kang 1, Su-Chang Lee 2 and Sang-Jin Yoon 3,\***

1 Department of Electrical Engineering, Pohang University of Science and Technology, Pohang 37673, Korea; ygchoi@postech.ac.kr(Y.-G.C.);hsasdf@postech.ac.kr(H.-S.L.);bkkang@postech.ac.kr(B.K.)


Received: 18 March 2019; Accepted: 27 March 2019; Published: 31 March 2019

**Abstract:** This paper proposes a grid-connected single-stage micro-inverter with low cost, small size, and high efficiency to drive a 320 W class photovoltaic panel. This micro-inverter has a new and advanced topology that consists of an interleaved boost converter, a full-bridge converter, and a voltage doubler. Variable switching frequency and advanced burst control schemes were devised and implemented. A 320 W prototype micro-inverter was very compact and slim with 60-mm width, 310-mm length, and 30-mm height. In evaluations, the proposed micro-inverter achieved CEC weighted efficiency of 95.55%, MPPT efficiency >95% over the entire load range, and THD 2.65% at the rated power. The proposed micro-inverter is well suited for photovoltaic micro-inverter applications that require low cost, small size, high efficiency, and low noise.

**Keywords:** single stage micro-inverter; burst control; variable frequency control; maximum power-point tracking
