Separate Voltage Sources Research Articles

Direct and Cross-Coupling Audio-Susceptibilities of the Peak Current-Mode Controlled Independent-Input Series-Output Boost Converter

This work studies the small-signal direct and cross-coupling audio-susceptibilities of the independent-input series-output boost converter with peak current-mode control. The converter functions in the continuous-conduction mode and comprises n-connected identical boost modules whose inputs are fed from separate voltage sources and outputs connected in series. Expressions for the module direct (self) and cross-coupling audio-susceptibilities are derived in symbolic form. The expressions explicitly show (n) as a variable and take into account the sampling action of the current loops. In addition, audio-susceptibilty frequency responses following the closure of the voltage feedback loops are generated and the influence of increasing n is discussed. Detailed simulations using PSIM are performed to support the analysis.

Phase-Variable Modeling and Comparative Study between a PMa-CPA and a CPA Alternator by Simulation Analysis

This paper presents the phase-variable modeling of a permanent magnet-assisted claw-pole alternator in PSIM simulation software tool with the performance compared with a claw-pole alternator model, which is a special case of the permanent magnet-assisted claw-pole alternator model with the rotor permanent-magnet flux constant setting equal to zero. The constructed model can be simulated as a real alternator directly connected to a diode-bridge rectifier or switch-mode rectifier circuit for the integrated power application system simulation analysis. The proposed model contains two features, one of which is that the stator and rotor windings are circuit-based. The other one feature is that the mechanical torque input is based on a mathematical function. In this model, the rotor position-dependent variable inductor is replaced by a separate voltage source according to the voltage source absorption theorem. The simulation shows that the proposed model has faster torque step response and higher power efficiency than the claw-pole alternator model. The proposed model can be employed to the application of the control design and simulation study of voltage regulation in automobiles. The simulation results with 15-V command and the load sudden change verify the correction of the proposed model.

Dual-model predictive control of two independent induction motors driven by a SiC nine-switch inverter

ABSTRACT This paper presents a finite control set model predictive control (FCS-MPC) approach for two induction machines driven by a nine-switch inverter (NSI). In the traditional approach, two separate voltage source inverters are necessary to drive the independent induction motors. In the proposed method, the nine-switch inverter is used to control the separate motors with a reduced number of switching devices compared to traditional method. A robust control strategy that eliminates the interactions between separate mechanical loads is required to achieve a proper independent speed and torque control for two induction machines through the NSI. To ensure the reliability of the machine operation, the indirect-field oriented control-based model predictive control strategy is proposed. The proposed control strategy is experimentally validated across the 3.2 kW SiC-based NSI prototype. The control algorithm is performed on an Altera Cyclone IV Field-programmable gate array. The experimental results demonstrate that the proposed dual-model predictive control method provides a good and robust motor control operation under different loading conditions. Two induction motors are successfully controlled, and the independent speed and torque control are achieved.

Variable Speed DC Generator Voltage Control using a Multistage Comparator

DC generator with variable rotation will produce uncontrolled voltage, causing problems in its utilization. In this study, it is proposed to develop a voltage control on the generator, in order to produce a fairly controllable and reliable voltage, with an analog circuit using a multistage comparator. Control of the generator output voltage is carried out by adjusting the field current from a separate voltage source which is forwarded to the resistance which is regulated based on the generator output voltage level with a multilevel comparison system. The results obtained are the output voltage ranges from 26 to 30 Volts and the output current ranges from 3 to 20 Amperes. This provides operational safety for the generator and battery. This technology can be used in dc generator systems in automotive engines, windmills, and other power plants.

Design and analysis of a Three Phase Transformerless Hybrid Series Active Power Filter based on sliding mode control using PQ-theory and stationary reference frames

In this work, a Three phase Transformerless Hybrid Series Active Power Filter (THSeAF) based on Sliding Mode Control (SMC) is proposed to mitigate the voltage and current distortions present in an electrical distribution systems (EDS). A Sliding Mode Controller is designed by controlling the parameters present on the load side as well as source side of the system. Three separate voltage source converters (VSC) are used. The mod1elling of the system is derived by considering a single-phase system by using state space analysis. The frequency response characteristics have been derived for the single-phase system and the stability of the system is studied. It is observed that the system has good stability margins when the SMC is applied at the source side compared to load side. Simulation results obtained in PSCAD/EMTDC v4.6 have been observed for power quality issues like voltage sags, voltage swells, voltage distortions, voltage unbalances and their concurrent occurrence. The approach of stationary reference frame was used for source side control and PQ theory is used for load side control. It is observed that the proposed controller works well in obtaining a stable and constant load voltage during these power quality issues. The difference in settling time observed is around 4 ms for the load side and source side control. The THD present in the load voltage is near about 1%. The SMC is found to be robust in obtaining a constant load voltage with low THD and an improved power factor.

Dual-Input Single-Output Isolated Resonant Converter with Zero Voltage Switching

A new modified LCLC series resonant circuit based dual-input single out-put isolated converter is proposed for hybrid energy systems. With this novel converter topology, two different voltage sources can be decoupled completely and transfer the power from two separate dc sources to dc load simultaneously. The proposed converter consists only two controllable switches for integrating two separate voltage sources; it can provide good voltage regulation and soft switching over wide load range. During unequal input voltages, the converter continues to maintain soft-switching and voltage regulation. The proposed converter operation and design considerations are outlined. A laboratory prototype rated for 250 Watt power at an output voltage of 380 V was built-up and tested. Experimental results confirm the functionality of the converter in terms of voltage regulation and soft switching over a wide load range.

Design, Control, and Experimental Test of an Open-Winding IPM Synchronous Motor

A concentrated winding interior permanent-magnet synchronous motor (IPMSM) capable of being used in wide speed range applications is designed and introduced. The IPMSM in the study is capable of being operated either from a single supply or from two converters in an open winding configuration. In this study, the phase windings are open connected to two separate voltage source converters: a dc-supplied main bridge, capable or supply real and reactive power, and a floating bridge (FB), connected to a capacitor and only capable of supplying reactive power to the motor. Vector diagram analysis and two-dimensional finite-element analysis (FEA) are presented to illustrate the extension of the capabilities of the IPMSM compared to the usual Y connection. The open winding IPMSM is built and performance experimentally investigated over a wide range of speeds. The results demonstrate 10–15% higher power capability using an open winding and FB, compared to the single inverter drive by experiments.

Secondary Side Output Voltage Stabilization of an IPT System by Tuning/Detuning through a Serial Tuned DC Voltage-controlled Variable Capacitor

This paper proposes a method to stabilize the output voltage of the secondary side of an Inductive Power Transfer (IPT) system through tuning/detuning via a serial tuned DC Voltage-controlled Variable Capacitor (DVVC). The equivalent capacitance of the DVVC changes with the conduction period of a diode in the DVVC controlled by DC voltage. The output voltage of an IPT system can be made constant when this DVVC is used as a variable resonant capacitor combined with a PI controller generating DC control voltage according to the fluctuations of the output voltage. Since a passive diode instead of an active switch is used in the DVVC, there are no active switch driving problems such as a separate voltage source or gate drivers, which makes the DVVC especially advantageous when used at the secondary side of an IPT system. Moreover, since the equivalent capacitance of the DVVC can be controlled smoothly with a DC voltage and the passive diode generates less EMI than active switches, the DVVC has the potential to be used at much higher frequencies than traditional switch mode capacitors.

Six-phase motor drive supplied by four voltage source inverters with synchronized space-vector PWM

Six-phase motor drive supplied by four voltage source inverters with synchronized space-vector PWMNovel method of space-vector-based pulsewidth modulation (PWM) has been disseminated for synchronous control of four inverters feeding six-phase drive based on asymmetrical induction motor which has two sets of windings spatially shifted by 30 electrical degrees. Basic schemes of synchronized PWM, applied for control of four separate voltage source inverters, allow both continuous phase voltages synchronization in the system and required power sharing between DC-sources. Simulations show a behavior of six-phase system with continuous and discontinuous versions of synchronized PWM.

A bridge-based temperature controller with a resistor as temperature sensor and heater

A resistance with a significant temperature coefficient (a pure metal, a semiconductor) incorporated in one arm of a new kind of bridge is used in a dual role: (i) as a temperature sensor or thermometer and (ii) as a power dissipator or load resistor. In this arrangement the bridge and the load resistor are fed from two separate voltage sources alternately. Power is supplied to the load resistor through a power regulator, (transistor, thyristor). The bridge signal is smoothed by a capacitor, amplified and used in a negative feedback loop for the temperature stabilization of the load resistor, or used in a positive feedback loop for various protection circuits. Applications of this new approach to gas chromatography DTA analysis, mass spectrometry and vacuum technology have been suggested.

Liquid Crystal Inversion Walls Caused by Field Fringing

Abstract A programmable nematic liquid crystal phase plate is formed by sandwiching a layer of liquid crystal material between two glass substrates, each coated with a transparent electrode. Regions of the liquid crystal layer are independently controlled by patterning the electrode into an array of pixels and addressing each pixel with a separate voltage source. The voltage-controlled reorientation (deformation) of the liquid crystal layer far from the pixel edges is well understood; however, very few investigations of the deformation near a pixel edge have been published. We show that near the pixel edges the deformation decreases monotonically, but a transition region located in the center of the pixel results. The transition region, called a liquid crystal inversion wall, is undesirable for most applications but can be forced to form near the edge of the pixel by adding a pretilt to the surface alignment. We present computer simulation results of the voltage-dependent pixel edge deformations and relate the deformations to the phase profile experienced by a wavefront propagating through the programmable phase plate.

Differential amplifier input impedance

The analysis of a simple differential amplifier excited by two separate voltage sources reveals that the input impedance which loads the voltage source at the inverting input is not a constant but rather is a function of the characteristics of each voltage source. An expression is derived for the input impedance and the result is illustrated in a simple example.