Partial resonance high frequency AC link converters are recognized to provide soft-switching, single-stage power conversion. They are highly reliable due to elimination of DC capacitors. Previous work has focused on proof of concept topologies and design requirements. In this work, a current regulated AC-DC converter from this family of converters is presented. The control design and grid integration requirements are discussed. An active damping method using grid current feedback is implemented to mitigate the filter resonance oscillations. The current control is implemented in the synchronous frame using voltage oriented control which enable power factor and power flow control. The result of converter operation and its control loops performances are presented
This paper investigates a new method to model and control variable-frequency power converters in a switching-synchronized sampled-state space for cycle-by-cycle digital control. There are a number of significant benefits in comparison to other methods including fast dynamic performance together with ease of design and implementation. Theoretical results are presented and verified through hardware, and simulations of a current-mode buck converter with constant on-time and a current-mode boost converter with constant off-time. Dynamic voltage scaling for microprocessors and LiDAR are among the a…
This paper presents a Direct Mapped Method (DMM) for real-time simulation of high switching frequency resonant converters. The DMM links state variables to diode statuses and provides an exact and noniterative solution to network equations. The proposed method is implemented on FPGA to simulate an LLC converter with switching frequencies ranging up to 500 kHz. The best reported implementations of DMM achieve a 25 ns simulation time-step for a wide range of clock frequencies, ranging from 40 MHz to 320 MHz.
This paper proposes a novel switching algorithm for modular multilevel converters (MMCs) that significantly reduces the switching frequency while fulfilling all control objectives required for their proper operation. Unlike in the conventional capacitor voltage-balancing strategies, in addition to submodule (SM) capacitor voltages, the proposed algorithm considers previous switching statuses during sorting. The algorithm is applied to a seven-level back-to-back MMC-HVDC system and tested under various operating conditions. Significant reduction in the switching frequency with trivial impacts o…
Unlike conventional converters, modular multilevel converter (MMC) has a higher switching frequency -- which has direct implication on important parameters like converter loss and reliability -- mainly due to increased number of switching components. However, conventional switching techniques, where submodule sorting is just based on capacitor voltage balancing, are not able to achieve switching frequency reduction objective. A novel modulation algorithm for modular multilevel converters (MMCs) is proposed in this paper to reduce the switching frequency of MMC operation by defining a constrain…
The power flow control of multi-active bridge converters requires a comprehensive steady-state analysis of the converter and the determination of conditions for zero voltage switching of all switching in the converter which result in minimum switching loss. This paper aims to model and carry out the power flow and Zero Voltage Switching (ZVS) analyses of Quad-active-bridge (QAB) dc-dc converter. The dynamic as well as the steady state analyses of the converter were carried out, thereby determining the phase shifts required to meet commanded load powers. The full equivalent circuit model of the…
Skipped Adjacency Pulse Width Modulation: Zero Voltage Switching over Full Duty Cycle Range for Hybrid Flying Capacitor Multi-Level Converters without Dynamic Level Changing
In automotive power electronics, distortion and electromagnetic interference (EMI) generated by the switching action of power semiconductors can be a significant challenge for the design of a compact, lightweight vehicle. As semiconductor switching frequencies increase, e.g., through the introduction of new materials, such as gallium nitride and silicon carbide, this problem becomes more severe. We present a control scheme for an automotive dc-to-dc converter that reduces the EMI generated by shaping switching distortion predictively at the run time. The multistep model-predictive control sche…
In this work, the problem of switching control design for DC-DC boost converter is considered, in the case of operation under uncertain equilibrium condition arising due to perturbations in the input and load parameters. Assuming that these uncertain parameters are generated via a known linear exo-system, a parameter estimator is designed to update the equilibrium point for the switching controller in real-time. In order to mitigate the noise amplification problem associated with the designed parameter estimator, the estimation error injection term is filtered via a set of first-order filters …
The design of gate drivers is an important topic in power converter topologies that can help reduce switching losses and increase power density. Gate driving techniques that offer zero-voltage switching and/or zero current switching have recently been successfully proposed for different modular multilevel converters such as the cascaded H bridge. Previous papers on other multilevel converters such as the multi-active bridge, however, do not sufficiently assess the topics of gate driver design for this topology. This work presents a novel isolated gate driver architecture tailored to the multi-…
Switched-capacitor (SC) DC-DC voltage converters are widely used in power delivery and management of modern integrated circuits. Connected to a common supply voltage, SC converters exhibit cross-regulation/coupling effects among loads connected to different SC converter stages due to the shared components such as switches, capacitors, and parasitic elements. The coupling effects between SC converter stages can potentially be used in covert communication, where two or more entities (e.g., loads) illegitimately establish a communication channel to exchange malicious information stealthily. To qu…
Controlling the Ćuk Converter using Piecewise Linear Lyapunov Functions
School of Electrical Engineering, University of Belgrade（贝尔格莱德大学电气工程学院）；Coordinated Science Laboratory, University of Illinois at Urbana-Champaign（伊利诺伊大学厄巴纳-香槟分校协同科学实验室）
Current-fed half bridge converter with bidirectional switches on ac side and a full bridge converter on dc side of a high frequency transformer is an optimal topology for single stage galvanically isolated ac-dc converter for onboard vehicle charging application. AC side switches are actively commutated to achieve zero current switching (ZCS) using single phase shift modulation (SPSM) and discontinuous current phase shift modulation (DCPSM). Furthermore, zero voltage turn-on (ZVS) is achieved for dc side switches. Compared to SPSM, DCPSM maintains a constant peak current in the converter throu…
This paper proposes a method of transferring physical continuous and switching/converter circuits working in continuous conduction mode (CCM) and discontinuous conduction mode (DCM) to graph representation, independent of the connection or the number of circuit components, so that machine learning (ML) algorithms and applications can be easily applied. Such methodology is generalized and is applicable to circuits with any number of switches, components, sources and loads, and can be useful in applications such as artificial intelligence (AI) based circuit design automation, layout optimization…
This paper proposes a new single input multiple output power supply by integrating a flyback converter and several buck converters. The flyback converter works as the main regulator, and the buck converters provide series voltage compensation with the aim of tight regulation. A time multiplexing switching scheme is proposed to deliver multiple output voltage levels via a two winding transformer and to eliminate the cross regulation between output channels. This configuration reduces the size of flyback transformer and filter capacitors, and consequently improves the overall form factor. A deta…
Electric Vehicle (EV) chargers are the need of the hour as EVs have invaded the commercial automobile market. The Three-Phase Three-Switch (TPTS) converter has features which make it ideal to act as the charging station because of its high efficiency at peak power rating. Traditionally, control of the TPTS converter has been achieved by the Space Vector (SV) based modulation scheme whose implementation is burdensome due to the trigonometric calculations involved. This paper introduces two simplified carrier based modulation schemes, which greatly reduce the implementation difficulty, as they r…
This paper analyses the capabilities of the OpenModelica environment to perform electromagnetic transient (EMT) type simulations of power transmission systems with grid-connected converters. A power transmission system has been modelled and simulated in OpenModelica and Simulink to compare both tools in terms of accuracy, robustness, flexibility and computational performance. Power system transient studies such as faults and switching of capacitor banks have been performed. The results confirmed an excellent overall agreement between both software and demonstrated a remarkable potential for us…
The use of charge controllers in photovoltaic generation systems increases the energy harvested significantly. The most efficient type of charge controller is the Maximum Power Point Tracking (MPPT) controller. The commercially available MPPT controller is limited to the input voltage of the solar panel and to the charging voltage of the battery making it inefficient to very low irradiance weather condition. In this paper, it is proposed to increase the efficiency of commercially available MPPT controllers by adding Power Management System that has boost converter and switching circuit that wi…
The increasing adoption of power electronic devices may lead to large disturbance and destabilization of future power systems. However, stability criteria are still an unsolved puzzle, since traditional small-signal stability analysis is not applicable to power electronics-enabled power systems when a large disturbance occurs, such as a fault, a pulse power load, or load switching. To address this issue, this paper presents for the first time the rigorous derivation of the sufficient criteria for large-signal stability in DC microgrids with distributed-controlled DC-DC power converters. A nove…
