Non‐electrolytic‐capacitor boost converter with non‐pulsating ripple‐free output current

Abstract

Summary A novel boost converter is proposed in this study, which is based on a newly designed impedance network, instead of using the traditional Z‐network structure and large electrolytic capacitors (ECs) to suppress current ripples. Besides, the proposed topology has ripple‐free output current, which is designed to improve the output current quality of the traditional boost converter and to enhance the voltage conversion ratio compared to the traditional Z‐network boost converter. The newly proposed impedance network consists of two inductor and capacitor (LC) pairs—one LC pair function as the intermediate energy transferring branch and the other pair as the output branch to obtain non‐pulsating output current. The operating principle and performance of the proposed converter are analyzed in detail for demonstrating its advanced features. Furthermore, the feasibility of the proposed converter topology is validated by its simulations and experimental studies. Compared to ECs, non‐electrolytic capacitors (NECs) have the benefit of low cost, small size, and long operating life, which brings high economical advantages to the proposed converter with enhanced voltage conversion performances.

Photovoltaic System for Microinverter Applications Based on a Non-Electrolytic-Capacitor Boost Converter and a Sliding-Mode Controller

“…The solution proposed in this paper improves the first stage of PV microinverters by enabling the implementation of a non-electrolytic DC-link using a new approach: developing the first stage using a non-electrolytic-capacitor (NEC) boost converter, which provides continuous output current, thus decreasing the DC-link capacitor needed to reduce the high-frequency current harmonics introduced to the second stage. This approach uses the NEC boost converter with non-pulsating and ripple-free output current proposed in [19], which introduces an improved impedance network (over the Z-network of the classical boost converter) but without changing the voltage conversion ratio and keeping the continuous input current condition. In addition, the PV system based on the NEC boost topology is analyzed in detail to provide a mathematical model and a comprehensive design procedure.…”

“…Continuous current Differential voltage sensor The input capacitor C pv is added to the NEC boost converter proposed in [19], which is used to set the operation voltage to the PV source. Moreover, the converter has two inductors, L 1 and L 2 , which are used to impose continuous current to both the input capacitor and output port, i.e., to the grid-connected inverter.…”

“…On the other hand, the voltage of the internal capacitor C cb affects the derivative of both i 1 and i 2 , as reported in ( 9) and ( 10); hence, C cb must be designed to have a small voltage ripple δv cb . Therefore, δv cb is selected as 10% of the steady-state value of v cb , which, according to expression (19), is equal to 48 V. In addition, the switching frequency of the NEC boost converter is selected to be below 100 kHz, which ensures the correct operation of commercial MOSFETs as observed in the implementation of the boost converter reported in [25]. Finally, Table 2 summarizes the design characteristics for the NEC boost converter for this example.…”

Modular DC‐DC converter with reduced current ripple and low voltage stress suitable for high voltage applications

“…Nevertheless, it requires a high duty cycle to attain high voltage gain. Also, the reverse recovery current issue in the output diodes and the high voltage stress upon semiconductors are other drawbacks of such structures 10 . Hence, various techniques have been developed to improve the boost topologies.…”

“…Also, the reverse recovery current issue in the output diodes and the high voltage stress upon semiconductors are other drawbacks of such structures. 10 Hence, various techniques have been developed to improve the boost topologies. One of these techniques used to boost the voltage gain is cascading method, which requires to be repeated for reaching the desired voltage gain.…”