Input parallel–output parallel connected modular nonisolated DC‐DC converters with current self‐sharing capability operating in discontinuous conduction mode

Abstract

This paper covers the self-sharing analysis of dc-dc nonisolated converters with input parallel-output parallel (IPOP) configuration and operating in discontinuous conduction mode (DCM). The main contribution of the proposed system is its capability of providing self-sharing of the currents on both sides of each individual converter, without average current sharing control, even in the face of parametric variations. This self-balance only occurs for DCM. When the addressed converters operate in continuous conduction mode (CCM), the self-sharing does not occur naturally under parametric differences among them, requiring the use of additional control loops. The use of self-sharing converters in nonisolated converters simplifies the control system, it makes the modular solution being attractive for many applications, and it increases the power range that the DCM converters may be applied. This paper brings the theoretical study of self-sharing of the current mechanism to six basic nonisolated converters operating in DCM. The self-sharing is verified by experimental results, which are obtained from three modules of dc-dc SEPIC converters. Both converters were designed to operate with 200-V input voltage, 125-V output voltage, 1500-W rated power (500 W each module), and switching frequency at 30 kHz.

Design of a Takagi–Sugeno Fuzzy Exact Modeling of a Buck–Boost Converter

“…Consider non-idealities results in more accurate models, including an accurate stationary value analysis [2]. With the ideal components set, the schematic considering the non-idealities of the components is depicted in Figure 3.…”

“…The state space representation was carried out according to de Kremes et al [2]; analyzing the circuit outlined in Figure 3, it has two operating stages: stage 1, with the Mosfet in conduction (Figure 4) and stage 2, with the diode in conduction (Figure 5).…”

“…Static power converters require control of their electrical variables, such as voltages, currents, and powers. To design suitable controllers, one needs to know the plant models of the power stage of the converter, which are usually in the form of transfer functions [1,2]. In this case, these transfer functions are obtained from linear differential equations, resulting from the linearization of nonlinear components bounded around the specific operating point of the converter power stage [2,3].…”

“…This work aims to develop the fuzzy TS model of a buck-boost converter, considering the non-idealities of the components [2], to be a test framework of nonlinear scenarios for a discrete PID controller designed by the pole cancelling method obtained through the linear model [25,26]. The premise is that the controller output voltage obtained linearly and designed to control the voltage only at the typical operating point can be tested at different operating points.…”

“…DC-DC converters can be conceptualized from a simple system consisting of a DC voltage source at the input, a DC-DC converter block, and a DC voltage source at the output. A DC-DC converter is an electronic circuit that processes a direct voltage at the input and transforms it into a direct voltage at the output, with active elements acting as switches, and passive components, usually inductors and capacitors, acting as controllers of the power flow between the sources [2].…”