Showing papers on "Voltage regulator published in 2011"

An Improved Maximum Power Point Tracking for Photovoltaic Grid-Connected Inverter Based on Voltage-Oriented Control

Abstract: In this paper, an improved maximum power point (MPP) tracking (MPPT) with better performance based on voltage-oriented control (VOC) is proposed to solve a fast-changing irradiation problem. In VOC, a cascaded control structure with an outer dc link voltage control loop and an inner current control loop is used. The currents are controlled in a synchronous orthogonal d,q frame using a decoupled feedback control. The reference current of proportional-integral (PI) d-axis controller is extracted from the dc-side voltage regulator by applying the energy-balancing control. Furthermore, in order to achieve a unity power factor, the q-axis reference is set to zero. The MPPT controller is applied to the reference of the outer loop control dc voltage photovoltaic (PV). Without PV array power measurement, the proposed MPPT identifies the correct direction of the MPP by processing the d-axis current reflecting the power grid side and the signal error of the PI outer loop designed to only represent the change in power due to the changing atmospheric conditions. The robust tracking capability under rapidly increasing and decreasing irradiance is verified experimentally with a PV array emulator. Simulations and experimental results demonstrate that the proposed method provides effective, fast, and perfect tracking.

A 48-Core IA-32 Processor in 45 nm CMOS Using On-Die Message-Passing and DVFS for Performance and Power Scaling

Abstract: This paper describes a multi-core processor that integrates 48 cores, 4 DDR3 memory channels, and a voltage regulator controller in a 64 2D-mesh network-on-chip architecture. Located at each mesh node is a five-port virtual cut-through packet-switched router shared between two IA-32 cores. Core-to-core communication uses message passing while exploiting 384 KB of on-die shared memory. Fine grain power management takes advantage of 8 voltage and 28 frequency islands to allow independent DVFS of cores and mesh. At the nominal 1.1 V supply, the cores operate at 1 GHz while the 2D-mesh operates at 2 GHz. As performance and voltage scales, the processor dissipates between 25 W and 125 W. The processor is implemented in 45 nm Hi-K CMOS and has 1.3 billion transistors.

Control of Electric Machine Drive Systems

Abstract: Preface. 1 Introduction. 1.1 Introduction. 1.2 Basics of Mechanics. 1.3 Torque Speed Curve of Typical Mechanical Loads. 2 Basic Structure and Modeling of Electric Machines and Power Converters. 2.1 Structure and Modeling of DC Machine. 2.2 Analysis of Steady-State Operation. 2.3 Analysis of Transient State of DC Machine. 2.4 Power Electronic Circuit to Drive DC Machine. 2.5 Rotating Magnetic Motive Force. 2.6 Steady-State Analysis of a Synchronous Machine. 2.7 Linear Electric Machine. 2.8 Capability Curve of Synchronous Machine. 2.9 Parameter Variation of Synchronous Machine. 2.10 Steady-State Analysis of Induction Machine. 2.11 Generator Operation of an Induction Machine. 2.12 Variation of Parameters of an Induction Machine. 2.13 Classification of Induction Machines According to Speed Torque Characteristics. 2.14 Quasi-Transient State Analysis. 2.15 Capability Curve of an Induction Machine. 2.16 Comparison of AC Machine and DC Machine. 2.17 Variable-Speed Control of Induction Machine Based on Steady-State Characteristics. 2.18 Modeling of Power Converters. 2.19 Parameter Conversion Using Per Unit Method. 3 Reference Frame Transformation and Transient State Analysis of Three-Phase AC Machines. 3.1 Complex Vector. 3.2 d q n Modeling of an Induction Machine Based on Complex Space Vector. 3.3 d q n Modeling of a Synchronous Machine Based on Complex Space Vector. 4 Design of Regulators for Electric Machines and Power Converters. 4.1 Active Damping. 4.2 Current Regulator. 4.3 Speed Regulator. 4.4 Position Regulator. 4.5 Detection of Phase Angle of AC Voltage. 4.6 Voltage Regulator. 5 Vector Control. 5.1 Instantaneous Torque Control. 5.2 Vector Control of Induction Machine. 5.3 Rotor Flux Linkage Estimator. 5.4 Flux Weakening Control. 6 Position/Speed Sensorless Control of AC Machines. 6.1 Sensorless Control of Induction Machine. 6.2 Sensorless Control of Surface-Mounted Permanent Magnet Synchronous Machine (SMPMSM). 6.3 Sensorless Control of Interior Permanent Magnet Synchronous Machine (IPMSM). 6.4 Sensorless Control Employing High-Frequency Signal Injection. 7 Practical Issues. 7.1 Output Voltage Distortion Due to Dead Time and Its Compensation. 7.2 Measurement of Phase Current. 7.3 Problems Due to Digital Signal Processing of Current Regulation Loop. Appendix A Measurement and Estimation of Parameters of Electric Machinery. A.1 Parameter Estimation. A.2 Parameter Estimation of Electric Machines Using Regulators of Drive System. A.3 Estimation of Mechanical Parameters. Appendix B d q Modeling Using Matrix Equations. B.1 Reference Frame and Transformation Matrix. B.2 d q Modeling of Induction Machine Using Transformation Matrix. B.3 d q Modeling of Synchronous Machine Using Transformation Matrix. Index.

Fault Ride-Through of a DFIG Wind Turbine Using a Dynamic Voltage Restorer During Symmetrical and Asymmetrical Grid Faults

Abstract: The application of a dynamic voltage restorer (DVR) connected to a wind-turbine-driven doubly fed induction generator (DFIG) is investigated. The setup allows the wind turbine system an uninterruptible fault ride-through of voltage dips. The DVR can compensate the faulty line voltage, while the DFIG wind turbine can continue its nominal operation as demanded in actual grid codes. Simulation results for a 2 MW wind turbine and measurement results on a 22 kW laboratory setup are presented, especially for asymmetrical grid faults. They show the effectiveness of the DVR in comparison to the low-voltage ride-through of the DFIG using a crowbar that does not allow continuous reactive power production.

A Fault Ride-Through Technique of DFIG Wind Turbine Systems Using Dynamic Voltage Restorers

Abstract: This paper proposes a low-voltage ride-through technique of a doubly fed induction generator (DFIG) wind turbine system using a dynamic voltage restorer (DVR). For effective control of the DVR, digital all-pass filters are used for extracting the positive-sequence component from the unbalanced grid voltage since they have the advantages of giving a desired phase shift and no magnitude reduction over conventional low- or high-pass filters. Using the positive-sequence component, the phase angles for the positive- and negative-sequence components of the grid voltage are derived. A control algorithm for the DVR that is dual voltage controllers only is implemented for the two sequence components in the dq synchronous reference frame. In order to achieve the power rating reduction of the DVR, the stator power reference for the DFIG is reduced during faults. In addition, a control scheme of pitch angle system is applied to stabilize the operation of the wind turbine system in the event of grid faults. PSCAD/EMTDC simulations show the effectiveness of the proposed technique and a feasibility of reducing the power rating of DVR for the fault ride-through capability of DFIG. The validity of the proposed control scheme for the DVR has also been verified by experimental results.

Novel Coordinated Voltage Control for Smart Distribution Networks With DG

Abstract: In this paper a novel coordinated voltage control scheme is proposed to enable voltage regulator to efficiently regulate the voltage of multiple feeders in the presence of DGs. The proposed technique is based on placing a remote terminal unit (RTUs) at each DG and each line capacitor. These RTUs coordinate together, through communication, and form a multiagent system. Detailed analysis is given for the estimation of the voltage profile based on the RTUs readings. The conditions under which the usage of one voltage regulator for the regulation of multiple-feeders fails are presented along with proposed solutions for such situation. Simulation results show that this technique enable a considerable increase in the allowed DG injected power to the system.

Method and system for harvesting rf signals and wirelessly charging a device

Abstract: System and method for harvesting radio frequency power from a wireless transmitter includes; an antenna having an output voltage, a matching network coupled to the antenna, a booster circuit coupled to the matching network and having an output voltage, and adapted to amplify the output voltage of the antenna. Matching network is adapted to match a power transfer. A voltage stabilizer circuit is adapted to stabilize the booster circuit output voltage. Method includes, determining at least one operating mode and charging a slave device from a master wireless transmitter located within a predetermined distance from the system. A rechargeable battery in the system is charged from a wireless transmitter, and a slave device is connected to the system. The slave device is charged from the rechargeable battery in the system.

Providing per core voltage and frequency control

Abstract: In one embodiment, the present invention includes a processor having a plurality of cores and a control logic to control provision of a voltage/frequency to a first core of the plurality of cores independently of provision of a voltage/frequency to at least a second core of the plurality of cores In some embodiments, the voltages may be provided from one or more internal voltage regulators of the processor Other embodiments are described and claimed

Common-Mode Circulating Current Control of Paralleled Interleaved Three-Phase Two-Level Voltage-Source Converters With Discontinuous Space-Vector Modulation

Abstract: This paper presents a control method to limit the common-mode (CM) circulating current between paralleled three-phase two-level voltage-source converters (VSCs) with discontinuous space-vector pulsewidth modulation (DPWM) and interleaved switching cycles. This CM circulating current can be separated into two separate components based on their frequency; the high-frequency component, close to the switching frequency, can be effectively limited by means of passive components; the low-frequency component, close to the fundamental frequency, embodies the jumping CM circulating current observed in parallel VSCs. This is the main reason why it is usually recommended not to implement discontinuous and interleaving PWM together. The origin of this low-frequency circulating current is analyzed in detail, and based on this, a method to eliminate its presence is proposed by impeding the simultaneous use of different zero vectors between the converters. This control method only requires six additional switching actions per line cycle, presenting a minimum impact on the converter thermal design. The analysis and the feasibility of the control method are verified by simulation and experimental results.

Voltage Stability Monitoring Based on the Concept of Coupled Single-Port Circuit

Abstract: This paper reveals that the impedance match (or the Thevenin circuit) based voltage stability monitoring techniques have problems to predict voltage stability limits when applied to multi-load power systems. Power system loads are nonlinear and dynamic. They cannot be simply represented as Thevenin circuit parameters for impedance match analysis. To overcome these difficulties, a new concept called “coupled single-port circuit” is proposed in this paper. The concept decouples a meshed network into individual single generator versus single bus network and, as a result, a modified version of the impedance match theorem can be used. This leads to a real-time voltage stability monitoring scheme without the need to estimate Thevenin parameters. The scheme can estimate voltage stability margin and identify weak areas in a system based on the SCADA and PMU data. Case studies conducted on several test systems have verified the validity of the proposed method.

VSC MTDC systems with a distributed DC voltage control - A power flow approach

Abstract: In this paper, a power flow model is presented to include a DC voltage droop control or distributed DC slack bus in a Multi-terminal Voltage Source Converter High Voltage Direct Current (VSC MTDC) grid. The available VSC MTDC models are often based on the extension of existing point-to-point connections and use a single DC slack bus that adapts its active power injection to control the DC voltage. A distributed DC voltage control has significant advantages over its concentrated slack bus counterpart, since a numbers of converters can jointly control the DC system voltage. After a fault, a voltage droop controlled DC grid converges to a new working point, which impacts the power flows in both the DC grid and the underlying AC grids. Whereas current day research is focussing on the dynamic behaviour of such a system, this paper introduces a power flow model to study the steady-state change of the combined AC/DC system as a result of faults and transients in the DC grid. The model allows to incorporate DC grids in a N-1 contingency analysis, thereby including the effects of a distributed voltage control on the power flows in both the AC and DC systems.

Improved Instantaneous Average Current-Sharing Control Scheme for Parallel-Connected Inverter Considering Line Impedance Impact in Microgrid Networks

Abstract: A new control scheme for parallel-connected inverters taking into account the effect of line impedance is presented. The system presented here consists of two single-phase inverters connected in parallel. The control technique is based on instantaneous average current-sharing control that requires interconnections among inverters for information sharing. A generalized model of a single-phase parallel-connected inverter system is derived. The model incorporates the detail of the control loops that use a proportional-resonant controller, but not the switching action. The voltage- and current-controller design and parameters selection process are discussed. Adaptive gain scheduling is introduced to the controller to improve the current and power sharing for a condition, where the line impedance is different among the inverters. The simulation results show that the adaptive gain-scheduling approaches introduced improve the performance of conventional controller in terms of current and power sharing between inverters under difference line impedance condition. The experiments validate the proposed system performance.

A Noninverting Buck–Boost DC–DC Switching Converter With High Efficiency and Wide Bandwidth

Abstract: A novel dc-dc switching converter consisting of a boost stage cascaded with a buck converter with their coils magnetically coupled is presented. The disclosed converter has the same step-up or step-down voltage conversion properties than the single inductor noninverting buck-boost converter but exhibits nonpulsating I/O currents. The converter control-to-output transfer function is continuous between operation modes if a particular magnetic coupling is selected. The addition of a damping network improves the dynamics and results in a control-to-output transfer function that has, even in boost mode, two dominant complex poles without right-half-plane zeros. An example shows that an output voltage controller can be designed with the same well-known techniques usually applied to the second-order buck regulator. Details of a prototype and experimental results including efficiency, frequency, and time domain responses are presented. The experimental results validate the theoretical expected advantages of the converter, namely, good efficiency, wide bandwidth, and simplicity of control design.

Parallel Three-Phase Inverters: Optimal PWM Method for Flux Reduction in Intercell Transformers

Abstract: Parallel multilevel converters are now widely used in the industry, particularly in high-current applications such as voltage regulator modules. The reduction of the output current ripple and the increase of its frequency are possible due to the use of interleaving techniques and, as a consequence, the filters associated with the converter may be reduced. The current ripple reduction in each commutation cell of a parallel converter is possible by the use of intercell transformers (ICT). The design of such a special magnetic component depends very strongly on the magnetic flux flowing through their cores. In three-phase systems coupled by ICTs, the injection of zero-sequence signals in the output voltage reference changes this flux. The aim of this paper is to explain the influence of the most popular pulse width modulation (PWM) methods regarding the ICT flux for applications to three-phase loads. An optimal PWM method that minimizes the size of the ICT design is developed. Experimental results verify the analysis presented in this paper and validate the flux reduction provided by the developed optimal zero-sequence signals.

Impact of high PV penetration on voltage regulation in electrical distribution systems

Abstract: Cloud-induced transients induced in photovoltaic (PV) power are considered as a potential barrier to further expansion when the penetration of this renewable generation resource reaches a high level in distribution systems. Such transients can cause voltage flicker or excessive operation of the voltage regulating equipment. This article studies these effects on part of a local distribution substation. Actual transformer load and solar irradiance data based on 1-minute interval are used to simulate the impact of 20% PV penetration on the feeder voltage during a time period that covers both clear and cloudy skies. Based on some specified conditions, the simulations indicate that voltage flicker is not a concern, but the tap changer operates excessively even when using a 5-minute time delay.

Performance Comparison of VSC-Based Shunt and Series Compensators Used for Load Voltage Control in Distribution Systems

Abstract: In this paper, the performance of voltage-source converter-based shunt and series compensators used for load voltage control in electrical power distribution systems has been analyzed and compared, when a nonlinear load is connected across the load bus. The comparison has been made based on the closed-loop frequency response characteristics of the compensated distribution system. A distribution static compensator (DSTATCOM) as a shunt device and a dynamic voltage restorer (DVR) as a series device are considered in the voltage-control mode for the comparison. The power-quality problems which these compensator address include voltage sags/swells, load voltage harmonic distortions, and unbalancing. The effect of various system parameters on the control performance of the compensator can be studied using the proposed analysis. In particular, the performance of the two compensators are compared with the strong ac supply (stiff source) and weak ac-supply (non-stiff source) distribution system. The experimental verification of the analytical results derived has been obtained using a laboratory model of the single-phase DSTATCOM and DVR. A generalized converter topology using a cascaded multilevel inverter has been proposed for the medium-voltage distribution system. Simulation studies have been performed in the PSCAD/EMTDC software to verify the results in the three-phase system.

Design and Fabrication of On-Chip Coupled Inductors Integrated With Magnetic Material for Voltage Regulators

Abstract: On-chip strip-line coupled inductors integrated with magnetic material are a promising technology option to enable on-chip voltage regulators for improving power management in microelectronics. We report on design methodologies where several examples of parameter tradeoffs are presented. When considered with practical integration constraints, these result in an optimized structure. Strip-line inductors integrated with Ni80Fe20 were then fabricated, electrically characterized, and compared to models. Electrical characterization included frequency dependent measurements of effective self and mutual inductance, effective resistance, coupling coefficient, and saturation effects.

Design Principles of a Symmetrically Coupled Inductor Structure for Multiphase Synchronous Buck Converters

Abstract: The multiphase interleaved synchronous buck converters with coupled phase inductors are being preferred for voltage regulator modules requiring low output voltage, high output current, and fast transient response since they simultaneously offer better steady-state efficiency and faster dynamic response. In this paper, a novel magnetic core structure for symmetrical coupling of multiphase buck converter phase inductors is proposed, which overcomes several limitations of asymmetrical inductor coupling proposed so far. A new analytical technique to arrive at simple dynamic equivalent circuits of the converter, as well as design guidelines for the proposed inductor structure, is presented. Experimental results from a prototype four-phase synchronous buck converter with the proposed inductor demonstrate 2% to 6% improvement in the converter efficiency compared to a similarly rated converter with uncoupled inductors while retaining the same transient performance.

Digitally Controlled Current-Mode DC–DC Converter IC

Abstract: The main focus of this paper is the implementation of mixed-signal peak current mode control in low-power dc-dc converters for portable applications. A DAC is used to link the digital voltage loop compensator to the analog peak current mode loop. Conventional DAC architectures, such as flash or ΔΣ are not suitable due to excessive power consumption and limited bandwidth of the reconstruction filter, respectively. The charge-pump based DAC (CP-DAC) used in this work has relatively poor linearity compared to more expensive DAC topologies; however, this can be tolerated since the linearity has a minor effect on the converter dynamics as long as the limit-cycle conditions are met. The CP-DAC has a guaranteed monotonic behavior from the digital current command to the peak inductor current, which is essential for maintaining stability. A buck converter IC, which was fabricated in a 0.18 μm CMOS process with 5 V compatible transistors, achieves a response time of 4 μs at fs=3nMHz and Vout=1 V, for a 200 mA load-step. The active area of the controller is only 0.077 mm2, and the total controller current-draw, which is heavily dominated by the on-chip senseFET current-sensor, is below 250 μA for a load current of Iout=50 mA.

An Active Voltage Doubling AC/DC Converter for Low-Voltage Energy Harvesting Applications

Abstract: This paper theoretically and experimentally investigates an ac/dc converter for low-voltage vibrational energy harvesting systems. The circuit employs an active-diode-based voltage doubler, where the output is a dc voltage that is twice the amplitude of the input ac voltage. Analytical solutions for the steady-state open-circuit voltage are derived, capturing the effects of the active-diode comparator hysteresis. It is shown that the hysteresis plays an important role in the rectification characteristics, circuit stability, and overall efficiency. Experimentally, the circuit is able to rectify input voltage amplitude as low as 5 mV and operates over a frequency range of 1 to 500 Hz, which spans most common mechanical vibrations. For input voltage amplitudes 250 mV or higher, the circuit exhibits >;80% efficiency for a range of load resistances, delivering 0.1-10 mW of power. Additionally, the circuit successfully rectifies the voltage from a vibrational energy harvester having a highly irregular and time-varying voltage waveform.

Investigation on Capacitor Voltage Regulation in Cascaded H-Bridge Multilevel Converters With Fundamental Frequency Switching

Abstract: Multilevel power electronic converters have gained popularity in high-power applications due to their lower switch voltage stress and modularity. Cascaded H-bridge converters are a promising breed of multilevel converters which generally require several separate dc voltage sources. By utilizing the redundant switching states, it is possible to replace the separate dc voltage sources with capacitors and keep only the one with the highest voltage level. Redundancy in the charge and discharge modes of the capacitors is assumed to be adequate for their voltage regulation. However, the effects of the output current of the converter as well as the time duration of the redundant switching states have been neglected. In this paper, the impacts of the connected load to the cascaded H-bridge converter as well as the switching angles on the voltage regulation of the capacitors are studied. This paper proves that voltage regulation is only attainable in a much limited operating conditions that it was originally reported. In addition, based on the analysis of the converter, a simplified formula is found which can be used to find those modulation indices that regulate the voltage of the capacitor. This formula can be used in harmonic minimization problems while capacitor voltage regulation is ensured. Simulation and laboratory results are provided to confirm the analysis.

A Dual-Loop Control Strategy of Railway Static Power Regulator Under V/V Electric Traction System

Abstract: For power quality in V/V traction system of the 350-km/h high-speed railway, a kind of railway static power conditioner (RPC) is discussed, which is used to carry out the comprehensive compensation of negative sequence and harmonic currents in the traction substation. In order to improve the control effect and performance of RPC, a dual-loop control strategy is constructed for RPC. Taking into account the disturbance and variation of electrified railway environment, a recursive proportional-integral control based on fuzzy algorithm is adopted to realize a fast and smooth tracking to the reference current. An energy-balance control is proposed to suppress the fluctuation of dc-link voltage and maintain the stability of RPC, which is an accurate and adaptive feedback control based on corresponding parameters. Finally, the correctness of the analysis proposed in this paper has been confirmed by the simulation and experiment results.

Data storage device employing cascaded voltage regulators during power failure

Abstract: A data storage device is disclosed comprising a non-volatile memory and control circuitry comprising an interface operable to receive a supply voltage, and a capacitor. An operating voltage regulator converts the supply voltage into an operating voltage used to operate the non-volatile memory. The supply voltage is used to charge the capacitor to a capacitor voltage higher than the supply voltage, and during a power failure, a backup voltage regulator converts the capacitor voltage into a backup voltage substantially equal to the supply voltage. The operating voltage regulator converts the backup voltage into the operating voltage used to operate the non-volatile memory.

Voltage and Frequency Controllers for an Asynchronous Generator-Based Isolated Wind Energy Conversion System

Abstract: This paper presents a state of art on voltage and frequency controllers (VFCs) for isolated asynchronous generators (IAGs) for standalone wind energy conversion systems. In wind turbine-driven IAG, magnitude and frequency of the generated voltage vary because of varying consumer loads and wide fluctuation in wind speeds. Therefore, new types of VF controllers based on a voltage source converter along with a battery energy storage system are proposed to maintain the voltage and frequency of IAG constant at varying wind speeds and varying consumer loads. A set of new VF controllers is designed and their performance is simulated in the MATLAB environment using Simulink and Sim-Power System toolboxes to study their behavior for standalone wind power generation.

Power supply circuit with adaptive input selection and method for power supply

Abstract: The present invention discloses a power supply circuit with adaptive input selection and a method for power supply. The power supply circuit includes: a charge pump for receiving at least one voltage and generating a boosted voltage; a first buck switching regulator coupled to a battery, for operating at least one first power transistor to convert a battery voltage to an output voltage according to a first control signal; a second buck switching regulator coupled to the charge pump, for operating at least one second power transistor to convert the boosted voltage to the output voltage according to a second control signal; and a controller generating the first control signal or the second control signal according to a level of the voltage of the battery, to select the first buck switching regulator or the second switching regulator for generating the output voltage.

Dynamic Bias-Current Boosting Technique for Ultralow-Power Low-Dropout Regulator in Biomedical Applications

Abstract: A dynamic bias-current boosting technique that concurrently enables ultralow-power operation and fast-transient behavior is presented in this brief. It is applied to an ultralow-power output-capacitor-free low-dropout regulator (LDO) to demonstrate the bandwidth extension provided during the transient periods. The proposed LDO is capable of providing 50 mA of output current with a minimum dropout voltage of 0.1 V. The ultralow-power LDO is implemented in a commercial 0.13-μm CMOS process, with power consumption of 1.20 μW only. Experimental results verify that both the load- and line-transient responses of the proposed LDO are significantly improved, and the settling times during load and line transients are shortened by as much as 33 and 3 times, respectively.

Switched Capacitor DC-DC Converter: Superior where the Buck Converter has Dominated

Abstract: The traditional inductor-based buck converter has been the default design for switched-mode voltage regulators for decades. Switched capacitor (SC) dc-dc converters, on the other hand, have traditionally been used in low power ( 80% over a load range of 5 mA to 1 A) than surveyed competitive buck converters, while requiring less board area and less costly passive components. The topology and controller enable a wide input range of 7.5 V to 13.5 V. Controls based on feedback and feedforward provide tight regulation under worst case line and load step conditions. This work shows that the SC converter can outperform the buck converter, and thus the scope of SC converter application can and should be expanded.

Bi-directional AC-DC/DC-AC converter for power sharing of hybrid AC/DC systems

Abstract: In this paper, some of the aspects related to the connectivity of DC microgrids to the main grid are investigated. A prototype system has been designed and implemented to address these aspects. The described system is dependent mainly on sustainable energy sources. Hence, a special care has been given to dealing with this kind of sources while designing different components of the system. Certain features had to be maintained in the system in order to assure efficient integration of different sources such as, efficient and reliable load-feeding capability and full controllability of voltage and power flow among various buses in the system. Two different converters have been investigated; firstly, a fully controlled rectifier has been designed to tie the DC grid with the AC one. A vector decoupling controlled sinusoidal pulse width modulation (SPWM) technique has been used to allow the designed rectifier to maintain a constant output voltage while being able to control the active and reactive power drawn from the grid independently. Hence, this controlled rectifier acts as a voltage regulator for the DC microgrid and has a uni-directional power flow capability from the AC grid to the DC microgrid. Moreover, in order to allow bi-directional power flow, a bi-directional AC-DC/DC-AC converter has also been designed. The Bi-directional AC-DC/DC-AC converter controls the active power transferred from the DC grid to the AC grid while operating at unity power factor. In addition, it controls the active power transferred from the AC grid to the DC grid while operating at unity power factor. Both simulation and experimental results verify the validity of the proposed system.