Active Rectifier Research Articles

Design and Implementation of Active PFC Rectifier Topology for Avionic and Fleet Electrification

Design and Implementation of Active PFC Rectifier Topology for Avionic and Fleet Electrification

Active and passive rectification methods for US-powered IMDs

In this paper the design of power management integrated circuits for the energy harvesting of ultrasound waves in implanted biomedical devices is addressed. In particular, the paper focuses on the main building block of the power conversion stage which is represented by the AC/DC converter. After an in-depth analytical description of cross-coupled passive and active rectifiers, a detailed design procedure for the common-gate comparator is introduced. Then a comparison between the different discussed topologies is carried through simulation results using a 28-nm standard CMOS technology. The results provide useful design guidelines in choosing the best topology according to the design specifications.

Real-time Simulation Framework for Validating Controllers of Virtual Synchronous Generators

The utilization of active rectifiers as converters in the interface between AC and DC microgrids has become a prevalent practice owing to their capacity to facilitate bidirectional power flow. The contemporary methodology for the development of power converters includes the integration of real-time simulation steps for the validation of control schemes and the assurance of safe implementation with hardware. The present study proposes a methodology for developing a real-time Hardware-in-theLoop (HIL) simulation framework, which aims to facilitate the rapid prototyping of advanced control algorithms for an ActiveFront-End (AFE) rectifier, especially a Virtual Synchronous Generator (VSG) control strategy. This approach aims to enhance the dynamic performance and stability of low-inertia power systems by mimicking the behavior of a synchronous generator, thereby providing virtual inertia to the power system. The control schemes and the primary circuit models are designed and implemented utilizing Matlab/Simulink and are optimized for code generation.

Multi-input SECE circuit with isolated active rectifier for piezoelectric energy harvesting

For multi-input piezoelectric energy harvesting, the issue of energy backflow between multiple Piezoelectric Transducer (PTZ) cause energy loss. Hence, an Isolated Active Rectifier (IAR) is proposed in this paper to address the problem. Based on the characteristic of energy isolation, the Multi-Input Synchronous Electric Charge Extraction Circuit (MI-SECE) with IAR can harvest energy from multiple PZTs with the arbitrary phase difference. The peak overall power conversion efficiency can reach up to 85.5%.

Single-Stage Active Rectifier With Wide Impedance Conversion Ratio Range for Inductive Power Transfer System Delivering Constant Power

Compared with the constant current (CC) charging mode, the constant power (CP) charging mode can speed up the battery charging rate and free the charger from excessive thermal design problems. However, the range of the battery's equivalent resistance in CP mode is wider than that in CC mode, which makes it difficult to track the optimal resistance of the inductive power transfer (IPT) system for efficiency enhancement. To solve this problem, this paper proposes a single-stage active rectifier (SSAR) integrating an interleaved buck converter with a full-bridge active rectifier (FBAR). Compared with the traditional FBAR, the resistance conversion ratio range of the SSAR is extended from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$[0, 8/\pi ^{2}]$</tex-math></inline-formula> to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$[0, 8]$</tex-math></inline-formula> , and the output current ripple is reduced due to the interleaved operation. A novel optimal phase angle control strategy is correspondingly proposed for the IPT system with the SSAR, which features advantages of wide impedance conversion ratio range, zero voltage switching (ZVS) turn-on of all MOSFETs, and no communication between the primary and the secondary sides. A 150 W experimental prototype is provided to verify the effectiveness of the proposed rectifier.

Regenerated Energy Absorption Methods for More Electric Aircraft Starter/Generator System

In more electric aircrafts, more motor loads are applied onboard. When the motor is braking, the regenerated energy need to be absorb to avoid dc-link voltage variations. Two regenerated energy absorption methods are proposed for the generator based on diode rectifiers and the starter/generator (SG) based on active rectifiers respectively. When the regenerated power is lower than other loaded power, both SG and generator systems can absorb it by reducing the output power. When the regenerated power is higher than other loaded power, if the SG is directly connected to the engine shaft, the regenerated energy can be absorbed by changing the SG operation from generating to motoring. The regenerated energy can be returned directly to the dc-link without extra devices and the dc-link voltage is under control during the regenerated energy absorption. The efficiency is improved and the heat is reduced by the proposed regenerated energy absorption methods. The generator and SG systems are implemented and the regenerated energy absorption methods are verified by experiments. The efficiency of the onboard electrical power system is improved.

A Weather-Independent and Renewable Power Supply With Wireless Power Transfer Feature for Powering Online Monitoring Systems in Smart Grid

The merge of the power and information infrastructures in smart grid requires increasing number of sensors and online monitoring systems on the high-voltage (HV) transmission towers. These systems are traditionally powered by small solar panels or wind turbines that are weather-dependent. This new contribution involves a full analysis of a complete weather-independent power supply to replace existing approaches. For the first time, the complete system comprising the energy harvesting, wireless power transfer (WPT) and output power stages is practically evaluated using printed circuit board (PCB) resonators embedded in a 35-kV composite insulator. We leverage the nearly constant current, transresistance, and voltage gains characteristics of the PCB domino-resonator structure under different self-oscillating frequencies and propose a coordinated control scheme of transmitter-side and receiver-side converters to regulate the constant current (CC) or constant voltage (CV) through entire charging process. Any current surge caused by the burst operation of the active rectifier on the receiver side triggers a transition between different self-oscillating operations on the transmitter side, leading to operating region extension of the active rectifier. Thus, the proposed system can easily adjust the output to follow different battery charging profiles without wireless communication between the transmitter and receiver.

An improved AAPI controller for enhanced DC-link transient performance of six-phase active rectifier application

The permanent magnet synchronous generators (PMSGs), especially those with multi-phase structure, are increasingly adopted to power large-scale vehicular system with DC distribution (e.g. more electric aircraft and electric-propulsion ship). The controller design is critical in these vehicular application as they are required to maintain desired transient performance under large system disturbances. In this paper, an improved adding a power integrator (AAPI) controller is designed and adopted to regulate the six-phase active rectifier, thus enhancing the transient performance of the system. The regulation of the multi-phase active rectifier feeding large amount of dynamic instantaneous constant power load (CPL) is firstly formulated as a second-order system by utilizing a bi-linear coordinate transformation. Then, an improved AAPI finite-time controller is designed considering both asymptotic stability and the transient stability of the system. Last but not least, the effectiveness of the proposal is validated by simulation.

Output Power Capacity Improvement Based on Three-Phase Current Balance Control for the Doubly Salient Electromagnetic Generator System

The doubly salient electromagnetic generator (DSEG) has the advantages of flexible control, high robustness, and low cost. Since multiple stator poles share a common set of field windings, the magnetic circuit of each phase is asymmetrical, which limits the output performance of the DSEG. The three-phase current balance control for the DSEG system was proposed. By investigating the current waveform under the angular position control (APC), a three-phase current prediction method was proposed. The conduction angle of the power switches in the active rectifier was predicted to make the three-phase current balanced. Based on the analysis and experiment, the current waveform was further analyzed, and the effectiveness of the three-phase current balance control was verified. Compared with the APC method, the output power capacity was improved using the three-phase current balance control under a limited winding current density. The maximum potential of the DSEG was explored, and the electromagnetic load capacity of the DSEG was fully released.

An Autonomous Electric Power System with a Permanent Magnet Synchronous Generator

The article deals with an autonomous electric power system (AEPS) with a permanent magnet synchronous generator (PMSG), storage battery (SB), and a static reversible converter (RC). The autonomous system has a transformer galvanic isolation between the AC and DC voltage networks. The converter operates in two modes: as a rectifier (the generator is in operation) and as an inverter (the generator is out of service). In the rectifier mode, the converter operates as an active voltage rectifier (AVR), which charges (recharges) the storage battery and stabilizes the generator voltage to form the main network. In the inverter mode, the converter operates as an autonomous voltage inverter to form a backup network. The autonomous electric power system structures were analyzed, and its two rational versions with the lowest current load of the converter have been selected based on the analysis results. One version of the structure, which contains, apart from the converter, an additional magnetizing device that stabilizes the generator voltage, operates with a DC network voltage of 250 ± 75 V. The other option does not contain an additional magnetizing device (MD) and operates with a DC network voltage of 600–640 V. For both versions, the automatic control system operating modes with stabilizing the generator voltage and charging the storage battery have been studied by simulating them on a computer.

Control over Grid Reactive Power by Using a Powerful Regenerative Controlled-Speed Synchronous Motor Drive

The authors propose a technique for reactive power compensation using a powerful regenerative controlled-speed synchronous motor drive (SMD) based on a three-level (3L) neutral point clamped (NPC) active front-end rectifier (AFE) and a voltage source inverter (VSI). The review of technical solutions for reactive power compensation showed that the limitations on the transmitted reactive power in the system under consideration still have not been studied. The paper provides a mathematical description and proposes synthesis-friendly block diagrams of the mathematical 3L-NPC-AFE-VSI and SMD models. The developed models allow defining the instantaneous values of the total 3L-NPC-AFE power consumed from the grid depending on the SMD load diagram. It is noted that the 3L-NPC-AFE-VSI-SMD system is designed without considering the opportunities for reactive power generation. It was determined that the limit value of reactive power generated by a 3L-NPC-AFE depends on the DC link voltage, the grid current consumption and the modulation index. The possibility of reactive power compensation by the SMD system through a 3L-NPC-AFE was experimentally tested on the main drive of a metal plate hot rolling mill. The analysis of the results obtained showed that during the breakdown, an SMD can generate reactive power equal to 16% of the total rated power using a 3L-NPC-AFE at a rated DC link voltage and without overcurrent. It was shown that generating reactive power is expedient in low-load SMD operation modes or at idle. Research in this area is promising due to the widespread use of high-power SMD based on a 3L-NPC-AFE-VSI and the tightening of requirements for energy saving and efficiency and supply voltage quality. The proposed reactive power control technique can be used as part of an industrial smart grid.

A Minimum ZVS Current Control Strategy of Semi Bridgeless Active Rectifier for Wide Operation Range Based on LCC-S Compensated WPT System

To meet the requirement of the battery charging characteristics and electric vehicle interoperability, wide power range and wide voltage range are important for the wireless electric vehicle (EV) charging system. Hence, ensuring zero voltage switching (ZVS) and high efficiency over the wide operating range is a hot issue but not well resolved. To address the current state of research, an efficiency-oriented control strategy is proposed for LCC-S compensated Wireless Power Transfer (WPT) system to achieve minimum ZVS current over a wide voltage and power regulation range. Based on the accurate harmonic-considered time-domain model, a universal design method for system parameters under the worst ZVS current conditions within wide operation range is proposed. Then, the universal explicit expression at the unit voltage gain point is given. Moreover, based on the simplified fitting method of piecewise bi-quadratic interpolation (PBQI), minimum ZVS current and minimum non-active current can be ensured over the full output voltage and output power range. A 3.3 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> W prototype has been built to verify that the converter can realize ZVS within the whole voltage range, the measured peak efficiency is about 95.2%.

A Wireless Hysteretic Controlled Wireless Power Transfer System With Enhanced Efficiency and Dynamic Response for Bioimplants

This article presents a 6.78-MHz wireless power transfer (WPT) system with system-level wireless hysteretic control technique and circuit-level designs for both the receiver (RX) and transmitter (TX) chips. The proposed system achieves RX local voltage regulation and TX global power regulation without using any off-chip components (e.g., MCU, DAC, or various controllers and decoders) nor TX current sensing coils, which were required in previous works. A higher light-load efficiency and instant load-transient response are also achieved with the proposed wireless hysteretic control because of its operation principle. To further improve the efficiency, dynamic switch timing calibrations in the active rectifier in the RX are also designed, with resolved dual steady-state operation issues during the transitions between on-/off-delay compensations. Both the RX and TX chips have been fabricated in 180-nm standard CMOS. Measurement results show a 68.9% peak end-to-end (E2E) efficiency, with an up-to-20% enhancement at light-load conditions over a previous non-linearly controlled WPT system design. When compared to the other state-of-the-art designs, this work achieves an overall higher E2E efficiency, unnoticeable under-/over-shoots with instant recovery in load transients, and a lower system complexity with a higher level of integration without using any extra components other than the LCs to close the wireless loop.

Stability Analysis of Active Front End and Permanent Magnet Synchronous Generator With Back EMF-Based Sensorless Control for DC Marine Vessels

This article studies the influence of sensorless control on the permanent magnet synchronous generator (PMSG) and pulsewidth modulation (PWM) converter (active front end rectifier, AFE) system for dc marine vessels. Back EMF-based sensorless control is adopted in this article because the minimum speed of PMSG in a dc marine vessel is enough for obtaining a sufficient back EMF signal. First, the output impedance of “PMSG+AFE” system with a typical topology and controller is deduced by small-signal analysis. The stability analysis with constant power load (CPL) is analyzed, including the influence of sensorless control bandwidth on PMSG with a significant per-unit impedance value. Since the inductance parameter affects both the current control and sensorless control, the influence of error in the estimated inductance parameter on the stability of “PMSG+AFE” system is analyzed. To verify the proposed impedance model, output impedance is measured in the simulation and experiment. The stability analysis with the proposed impedance model and load impedance of CPL is provided in MATLAB, and simulation results and experimental measurements are given to verify the analysis.

A Power Management System for Hybrid Energy Harvesting From Multiple Multitype Sources and Ultrawide Range Source Tracking

This article presents a power management system (PMS) for hybrid energy harvesting from multiple multitype sources. Three key features of the proposed approach are 1) a simple architecture for hybrid energy harvesting from multiple multitype sources by sharing a single inductor, 2) a backup power controller (BPC) for recycling surplus energy, and 3) an efficient boost–buck conversion (B2C) mode for tracking multiple sources within a single cycle. The power stages of the PMS consist of an active bias-flip rectifier (ABFR) for ac sources, three input low-voltage boost converters (3LVBC), and a high-voltage buck converter for dc sources. The B2C mode efficiently combines the operation of the 3LVBC and HVBC. By sharing an inductor in B2C mode, the ABFR increases the overall input power ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">IN</sub> ) by aggregating the power from the hybrid sources. The proposed PMS operates under four modes depending on the load conditions detected by the BPC. This approach improves the average harvesting efficiency using the auxiliary output paths and two storage nodes. For per-source maximum power point tracking, adaptive impedance matching and perturb and observe techniques are used. The integrated circuit (IC) part of the PMS is fabricated in a 180 nm process. The measured tracking efficiency is higher than 92% for a wide source resistance range from 2 Ω to 2 kΩ (1000× range). An end-to-end efficiency of up to 92.5% is achieved. The energy harvesting from multiple multitype sources significantly extends the output power range from 0.053 μW to 132600 μW. All the functions of the IC are realized with only 900 nW.

Performance Optimization of SSHC Rectifiers for Piezoelectric Energy Harvesting

In the past decades, inductor-based synchronized switch harvesting on inductor (SSHI) rectifiers have been widely employed in many active rectification systems for piezoelectric energy harvesting. Although SSHI rectifiers achieve high energy extraction performance compared to passive full-bridge rectifier (FBR), the performance greatly depends on the inductor employed. While a larger inductor can achieve higher performance, the system form factor is also increased, which is counter to system miniaturization in many applications. To solve this issue, an efficient synchronized switch harvesting on capacitors (SSHC) rectifier was proposed recently. Instead of using large inductors, the SSHC rectifier employs on-chip or off-chip flying capacitors to achieve comparable or higher performance. In previous studies, the flying capacitors are chosen equal to the inherent capacitance of the piezoelectric transducer (PT) to achieve 1/3 voltage flipping efficiency <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$(\eta _{F})$ </tex-math></inline-formula> for a 1-stage SSHC rectifier and 4/5 flipping efficiency for a 8-stage SSHC rectifier. This brief presents that the flipping efficiency can be further increased to 1/2 for a 1-stage SSHC rectifier if the flying capacitor is chosen to be much larger than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$C_{P}$ </tex-math></inline-formula> and the 4/5 flipping efficiency can be achieved by employing only 4 flying capacitors.

Mitigating Electrical Disturbances with Hybrid Distribution Transformer

Hybrid transformers (HT) have the advantages of the conventional transformer, the regulatory abilities of power electronic converters, and reduce the impact of the grid. The impacts of the existing grid are voltage sag, voltage swell, harmonic distortion, and voltage unbalanced. The power electronic converter has a controllable advantage such as regulating the voltage and can transfer only a fraction of the power. The aim of the paper is to augment the conventional power distribution transformer with a partially rated power electronic module to enhance flexibility and introduce new features to the distribution transformer. In this paper, the proposed back-to-back converter included an active front rectifier and a modular multilevel converter (MMC) was simulated by MATLAB/Simulink software. The proposed back-to-back converter was used at the primary side of the distribution transformer to compensate for the voltage sag and swell issues. The simulation results were obtained under different conditions such as various supply voltages and various loads. Hence, the proposed system has the ability to regulate the output voltage under various conditions with ±10%.

Direct Power Control of a Bipolar Output Active Rectifier for More Electric Aircraft Based on an Optimized Sector Division

This paper presents a novel direct power control (DPC) strategy based on an optimized sector division for a three-phase coupled inductor-based bipolar output active rectifier (TCIBAR) applied in more electric aircraft (MEA). First, based on the instantaneous power theory, the power model of the TCIBAR is built in the synchronous rotating coordinate system. Second, to implement the hysteresis power control of TCIBAR without causing the runaway of the zero-sequence current in the three-phase coupled inductor (TCI), a set of new voltage vectors that have the same zero-sequence voltage (ZSV) component are synthesized and adopted in the proposed DPC strategy. Third, by quantitatively analyzing the effect of the new synthesized voltage vectors on the power variation of TCIBAR, an optimized sector division method is proposed to improve the accuracy of power control and reduce the phase current harmonics in TCIBAR. Finally, to maintain the voltage balance of the bipolar dc ports in TCIBAR, voltage balance control is studied in the proposed DPC strategy. The proposed DPC strategy is researched on an experimental platform of TCIBAR, and the results show that the proposed DPC strategy is feasible and has good static and dynamic performance.

Virtual Vector-Based Direct Power Control of a Three-Phase Coupled Inductor-Based Bipolar-Output Active Rectifier for More Electric Aircraft

Direct power control (DPC) has gained increasing attention in recent years as a simple and efficient control strategy for pulse width modulation (PWM) rectifiers. In this paper, the idea of DPC is introduced into the three-phase coupled inductor-based bipolar-output active rectifier (TCIBAR) for the first time, and a virtual vector-based direct power control (VVB-DPC) strategy is proposed for TCIBAR to realize the bipolar DC power supply for more electric aircraft (MEA). First, the mathematical model of the TCIBAR is deduced, and the basic principle of the classic DPC strategy is reviewed. On this basis, the limitations of the classic DPC strategy in TCIBAR control are analyzed. Second, a set of virtual vectors are derived to establish a novel virtual-vector switching table. Based on the virtual-vector switching table, the hysteresis power control of TCIBAR can be realized without affecting the DC-side neutral-point potential of TCIBAR. Finally, a neutral-point potential control method based on DPC architecture is studied and integrated into the VVB-DPC strategy to maintain the bipolar DC voltage balance of TCIBAR under unbalanced load conditions. The VVB-DPC strategy is experimentally studied on a TCIBAR prototype, and the experimental results verify the feasibility and effectiveness of the proposed strategy.

Efficient Dual Output Regulating Rectifier and Adiabatic Charge Pump for Biomedical Applications Employing Wireless Power Transfer

A power management unit (PMU) is an essential block for diversified multi-functional low-power Internet of Things (IoT) and biomedical electronics. This paper includes a theoretical analysis of a high current, single-stage ac-dc, reconfigurable, dual output, regulating rectifier consisting of pulse width modulation (PWM) and pulse frequency modulation (PFM). The regulating rectifier provides two independently regulated supply voltages of 1.8 V and 3.3 V from an input ac voltage. The PFM control feedback consists of feedback-driven regulation to adjust the driving frequency of the power transistors through adaptive buffers in the active rectifier. The PWM/PFM mode control provides a feedback loop to adjust the conduction duration accurately and minimize power losses. The design also includes an adiabatic charge pump (CP) to provide a higher voltage level. The adiabatic CP consists of latch-up and power-saving topologies to enhance its power efficiency. Simulation results show that the dual regulating rectifier has 94.3% voltage conversion efficiency with an ac input magnitude of 3.5 Vp. The power conversion efficiency of the regulated 3.3 V output voltage is 82.3%. The adiabatic CP has an overall voltage conversion efficiency (VCE) of 92.9% with a total on-chip capacitance of 60 pF. The circuit was designed using 180 nm CMOS technology.