Constant DC-capacitor Research Articles

Constant DC-Capacitor Voltage-Control-Based Reactive Power Control Method of Bidirectional Battery Charger for EVs in Commercial Single-Phase Three-Wire Low-Voltage Feeders

Constant DC-Capacitor Voltage-Control-Based Reactive Power Control Method of Bidirectional Battery Charger for EVs in Commercial Single-Phase Three-Wire Low-Voltage Feeders

Simple Power Quality Compensation with Bidirectional Battery Charger for Electric Vehicles in Single-Phase Three-Wire Distribution Feeders

This paper deals with power quality compensation in single-phase three-wire distribution feeders using a constant DC-capacitor voltage-control (CDCVC)-based strategy of the previously proposed bidirectional battery charger (BBC) for electric vehicles under the distorted source-voltage and load-current conditions. Instantaneous active power flowing into the three-leg pulse-width-modulated (PWM) rectifier in the BBC is discussed. The instantaneous power flowing into the three-leg PWM rectifier demonstrates that the CDCVC-based strategy obtains balanced and sinusoidal source currents at a unity power factor, where the source-side active power is balanced with the load-side active power. Simulation and experimental results demonstrate that balanced and sinusoidal source currents at a unity power factor are attained in single-phase three-wire distribution feeders with both battery-charging and -discharging operations for electric vehicles even though both source voltage and load currents are distorted.

Harmonic Current Compensation Using Constant DC-Capacitor Voltage-Control-Based Strategy of Three-Level Neutral-Point-Clamped Inverter-Based STATCOM with Reactive Power Control

Harmonic Current Compensation Using Constant DC-Capacitor Voltage-Control-Based Strategy of Three-Level Neutral-Point-Clamped Inverter-Based STATCOM with Reactive Power Control

Constant DC-Capacitor Voltage-Control-Based Strategy for Harmonics Compensation in Smart Charger for Electric Vehicles in Single-Phase Three-Wire Distribution Feeders with Reactive Power Control

Constant DC-Capacitor Voltage-Control-Based Strategy for Harmonics Compensation in Smart Charger for Electric Vehicles in Single-Phase Three-Wire Distribution Feeders with Reactive Power Control

Improvement in Harmonic Compensation of a Smart Charger with a Constant DC-Capacitor Voltage-Control-Based Strategy for Electric Vehicles in Single-Phase Three-Wire Distribution Feeders

This paper presents an improvement in harmonic compensation performance of a previously proposed smart charger (SC) with a constant dc-capacitor voltage-control (CDCVC) strategy for electric vehicles (EVs) in single-phase three-wire distribution feeders (SPTWDFs). A controller for 3rd harmonic currents in d-q coordinates is added to the previously proposed SC. This addition improves harmonic compensation performance of the source currents. We briefly introduce harmonic current compensation using the previously proposed CDCVC-based algorithm for the SC. Then, the basic principles of the proposed controller for the 3rd harmonic currents in d-q coordinates are discussed in detail. It is shown that synchronization of the current controllers for both the fundamental and 3rd harmonic components is required. The switching frequency of a three-leg pulse-width modulated rectifier with a bidirectional dc–dc converter, which performs the SC, is determined considering the synchronization of the current controllers. Simulation and experimental results demonstrate that balanced and sinusoidal source currents with a unity power factor are achieved during both battery charging and discharging operations in EVs, improving the harmonic compensation performance of the previously proposed SC. Experimental results also demonstrate that the total harmonic distortion values of source currents are improved by 8.4% and 3.6% with the proposed controller for 3rd harmonic currents, when the SC is discharging, for example.

Constant DC-Capacitor Voltage-Control-Based Harmonics Compensation Strategy of Smart Charger for Electric Vehicles in Single-Phase Three-Wire Distribution Feeders

This paper discusses harmonic current compensation of the constant DC-capacitor voltage-control (CDCVC)-based strategy of smart chargers for electric vehicles (EVs) in single-phase three-wire distribution feeders (SPTWDFs) under nonlinear load conditions. The basic principle of the CDCVC-based harmonics compensation strategy under nonlinear load conditions is discussed in detail. The instantaneous power flowing into the three-leg pulse-width modulated (PWM) rectifier, which performs as a smart charger, shows that the CDCVC-based strategy achieves balanced and sinusoidal source currents with a unity power factor. The CDCVC-based harmonics compensation strategy does not require any calculation blocks of fundamental reactive, unbalanced active, and harmonic currents. Thus, the authors propose a simplified algorithm to compensate for reactive, unbalanced active, and harmonic currents. A digital computer simulation is implemented to confirm the validity and high practicability of the CDCVC-based harmonics compensation strategy using PSIM software. Simulation results demonstrate that balanced and sinusoidal source currents with a unity power factor in SPTWDFs are obtained on the secondary side of the pole-mounted distribution transformer (PMDT) during both the battery-charging and discharging operations in EVs, compensating for the reactive, unbalanced active, and harmonic currents.

Harmonic Mitigation Using DC Self Supported Shunt Active Power Filter

The advent of semiconductor technology has resulted in increased application of power electronic devices in industrial as well as domestic loads, a combination of which acts as a non-linear load. These non-linear loads are responsible for increased harmonics by drawing a distorted current from the supply system, leading to deterioration of source currents and voltages. This work proposes a method to improve the power quality with the aid of a three-phase shunt active power filter (SAPF) implementing a controlled voltage source inverter and synchronous d-q reference current generation technique for reference current generation of hysteresis controller. A discrete PI controller has been implemented to maintain a constant DC capacitor link voltage. The proportional and integral gains of the PI controller have been computed with the help of bacterial foraging optimization technique. The proposed SAPF for a three phase three wire system employing a balanced non-linear load has been simulated on MATLAB software to validate its performance. The simulation results demonstrate satisfactory performance of the proposed SAPF by effectively compensating harmonics of the supply system and lowering THD such that they fall within IEEE 519 standards for harmonic levels.

Novel Reactive Power Control Strategy Based on Constant DC-Capacitor Voltage Control for Reducing the Capacity of Smart Charger for Electric Vehicles on Single-Phase Three-Wire Distribution Feeders

This paper proposes a novel reactive power control strategy to reduce the capacity of the previously proposed smart charger for electric vehicles (EVs) on single-phase three-wire distribution feeders. The proposed reactive power control strategy is based on the constant dc-capacitor voltage control of the grid-connected pulsewidth-modulated rectifier. Any calculation blocks of the load-side active current are not needed. Thus, we offer the simplest reactive power control strategy. The basic principle of the proposed reactive power control strategy is discussed in detail, and then confirmed by a digital computer simulation using the PSIM software. A prototype experimental model is constructed and tested. Experimental result demonstrates that balanced source currents with a power factor of 0.9, which is an acceptable value in Japanese home appliances, are obtained on the secondary side of the pole-mounted distribution transformer during the battery charging operation in the EVs, reducing the capacity of the smart charger by 36% as compared with that of the smart charger with the previously proposed control strategy.

Reactive Power Control Strategy Based on DC Capacitor Voltage Control for Active Load Balancer in Three-Phase Four-Wire Distribution Systems

This paper proposes a reactive power control strategy for the active load balancer (ALB) in three-phase four-wire distribution systems. The proposed reactive power control strategy is based on constant DC capacitor voltage control, which is always used in active power line conditioners. Therefore, the proposed reactive power control strategy does not require active, reactive calculation blocks of load currents for the reference source current calculation. Balanced source currents with a predefined power factor can be achieved without unbalanced active and reactive components detection of the load currents. The basic principle of the reactive power control strategy for the ALB is discussed in detail, and then confirmed by digital computer simulation using PSIM software. A prototype experimental model is constructed and tested to validate the feasibility of the proposed control algorithm. Simulation and experimental results demonstrate that balanced source currents with a predefined power factor are achieved in three-phase four-wire distribution systems.

Constant DC Capacitor Voltage Control based Strategy for Active Load Balancer in Three-phase Four-wire Distribution Systems

Constant DC Capacitor Voltage Control based Strategy for Active Load Balancer in Three-phase Four-wire Distribution Systems

A novel active power quality compensator topology with DC voltage balancer for electrified railways

AbstractThis paper proposes a novel active power quality compensator (APQC) topology with a DC voltage balancer for electrified railways. The APQC is composed of a three‐leg structure with two common DC capacitors. Two legs perform as two half‐bridge inverters, which compensate the unbalanced active, reactive, and harmonic currents on the source side in the traction substation. The third leg controls two common DC capacitor voltages with a small amount of the output currents. Therefore, the current rating of the third leg can be reduced as compared to that of the already proposed three‐leg structured APQC. In the control algorithm of the two half‐bridge inverters, a strategy based on constant DC capacitor voltage control is used, which does not need any calculation blocks of the unbalanced active, reactive, and harmonic components of the load current to perform the APQC operation. Thus we offer the simplest algorithm for the proposed APQC. The basic principle of the proposed APQC topology with the DC voltage balancer is discussed in detail, and then confirmed by digital computer simulation using the PSIM software. A prototype experimental model is constructed and tested. Experimental results demonstrate that the proposed APQC can achieve balanced and sinusoidal source currents on the primary side of the Scott transformer in traction substations for electrified railways. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

A constant DC voltage control‐based strategy for an active power quality compensator in electrified railways with improved response

AbstractThis paper proposes a constant DC voltage control‐based strategy for an active power quality compensator (APQC) used in electrified railways. The proposed strategy consists of only an I‐PD‐based constant DC capacitor voltage control with an added moving‐average type low‐pass filter (LPF). The added LPF improves the response of the constant DC capacitor voltage control for the APQC. Thus we offer the simplest control method for the APQC used in electrified railways with improved response. The basic principle of the proposed control strategy is discussed in detail, and then confirmed by digital computer simulation using the PSIM software. A prototype experimental model is constructed and tested. Experimental results demonstrate that balanced source currents with unity power factor are obtained on the primary side of the Scott transformer in the traction substation systems, improving the response by one‐fourth as compared to that of the previously proposed control method. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

A constant DC voltage control based compensation method of an active power quality compensator for electrified railways

AbstractThis paper proposes a novel and simple control method for the active power quality compensators (APQCs) used in electrified railways. The proposed method uses only the constant dc capacitor voltage control block, which is commonly used in the APQCs. No detection blocks of the harmonic, reactive, and negative‐sequence components are necessary. Thus we offer the simplest way to compensate the harmonic, reactive, and negative‐sequence currents on the primary side of the Scott transformer in the traction substation. The basic principle of the proposed control method is discussed in detail, and then confirmed by digital computer simulation usingPSIM software. A prototype experimental model is constructed and tested. Experimental results demonstrate that the balanced source currents with the unity power factor are obtained on the primary side with the proposed control method, which uses only the constant dc capacitor voltage control. Copyright © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

相関関数を用いた平衡化機能付き障害電流補償装置の直流コンデンサ電圧一定制御法の検討

This paper discusses the constant DC capacitor voltage control method of the non-active current compensator using the correlation function. The linearized model of the constant do capacitor voltage control block is derived, and then the relationship between the capacitance of the do capacitor and power flows into the non-active current compensator. It is shown that the capacitance can be decided considering only the power flow caused by the unbalanced situation. Digital computer simulation is implemented to verify the validity of the linearized model. The prototype experimental model is constructed and tested. Experimental results demonstrate that the linearized model is useful to design the do capacitor and PI controller.