Power Electronics Building Blocks Research Articles

New solutions for a low-cost power electronic building block for matrix converters

This paper analyzes some aspects of integrating the matrix converter (MC) bidirectional switches into a power module. The analysis produces two optimal topologies for a power module: one for low-power and another for medium/high-power MCs. A new power module topology for a low-power three-phase-to-three- phase MC is proposed. By using bootstrap circuits to feed the gate-drivers, the proposed configuration requires only three insulated power supplies for a complete MC. This proposal constitutes a solution recommended in the low-power range, where low cost and low volume are the main objectives. Furthermore, a configuration of a power electronic building block for MCs is proposed. This includes the commutation control logic and the overcurrent protection, provides safe operation, and eliminates the specific problem of operating the bidirectional switches.

PEBB System Stability Margin Monitoring

PEBB (power electronics building block) systems are typical nonlinear systems. Under the conventional but still popular linear control design, the system stability margin varies from one operating point to another. This paper introduces a novel approach to monitoring the DC bus stability margin of a PEBB system online. At the steady state of the system, a small-signal perturbation current î p is injected into the DC bus, and the load-side response current î L is measured. By checking the validation |î L (jw)| < |î p (jw)|, the system stability margin can be examined. Experiments on a 48 V DC DPS demonstrate the proposed measurement approach. An implementation approach is also proposed for an 800 V DC PEBB-based testbed system.

Dynamics Analysis of Parallel Three-Phase Converters

In a distributed power system based on power electronics building blocks (PEBBs), it is desirable to use a parallel structure with standardized PEBB modules in order to increase power level, provide redundancy and improve system performance. Nonlinear couplings and interactions, however, may occur among the parallel modules. Compared with their counterpart DC/DC converters, three-phase AC/DC or DC/AC converters exhibit stronger dynamics when they operate in parallel. The objective of this paper is to comprehensively analyze the nonlinear dynamics among two parallel three-phase converters. The paper firstly develops a nonlinear average model in rotating coordinates. Based on the model, the nonlinear dynamics, such as small-signal interaction, zero-sequence circulating current and high frequency noise, are analyzed. To improve the system performance and minimize the interactions, some feedback control strategies are proposed. To deal with high-frequency noise, a feedforward control scheme is proposed. The scheme can significantly reduce both common-mode and differential-mode noise. Simulations and preliminary experimental results are presented.

An innovative technique for packaging power electronic building blocks using metal posts interconnected parallel plate structures

Power electronics building blocks (PEBBs) are envisioned as integrated power modules consisting of power semiconductor devices, power integrated circuits, sensors, and protection circuits for a wide range of power electronics applications, such as inverters for motor drives and converters for power processing equipment. At the Center for Power Electronics Systems, we developed a topology for a basic building block-a two-switch two-diode half-bridge converter in totem-pole configuration with built-in gate-driver and protection circuitry, fiber-optic receiver/transmitter interface, and soft-switching capability. Based on the topology, a series of prototype modules, with 600 V, 3.3 kW rating, were fabricated using an innovative packaging technique developed for the program-metal posts interconnected parallel plate structure (MPIPPS). This new packaging technique uses direct attachment of bulk copper, not wire-bonding of fine aluminum wires, for interconnecting power devices. Electrical performance data of the packaged devices show that an air-cooled 15 kW inverter, operating from 400 V dc bus with 20 kHz switching frequency can be constructed by integrating three prototype modules, which is almost double what could be achieved with commercially packaged devices of the same rating.

Modeling, control and stability analysis of a PEBB based DC DPS

The Power Electronic Building Block (PEBB) concept is to provide generic building blocks for power conversion, regulation and distribution with control intelligence and autonomy. A comprehensive modeling and analysis of a PEBB based DC distribution power system (DPS), comprising of a front end power factor correction (PFC) boost rectifier, a DC-DC converter and a three phase four leg inverter, is performed. All the subsystems of the DC DPS are modeled and analyzed for stability and good transient performance. The effect of impedance overlap on the system and individual subsystems is examined. Ability of a PEBB based converter to stabilize the integrated system by actively changing the system bandwidth is presented.

Performance characteristics and average-value modeling of auxiliary resonant commutated pole converter based induction motor drives

The auxiliary resonant commutated pole (ARCP) power converter is currently of intense interest for use in a variety of power electronic converters, and is one of the cornerstones of the US Navy's power electronic building block (PEBB) effort. In this paper, a detailed discussion of the required switching times needed to achieve completely soft switching operation with only one current sensor per phase is set forth. Based on this analysis, an average-value model of the ARCP converter is derived and used to explore its output characteristics. It is shown that large loads at high power factors can cause the ARCP output voltage to drop substantially. Computer simulations and laboratory data are used to validate this analysis.