Duty Ratio Control Research Articles

Primary side control strategies for battery charging regulation in wireless power transfer systems for EV applications

AbstractResonant inductive‐based wireless power transfer (WPT) for battery charging has potential applications in electric vehicles (EVs). The EV battery charging process requires the regulation of both charging voltage and current. Duty ratio or frequency control is generally preferred to manage the power flow between the transmitter and receiver coils in the WPT system. In the case of WPT charging, misalignment between the coils and parameter variations are unavoidable issues that result in changes to the output power. Therefore, it is essential to control the power flow to maintain constant current (CC) and constant voltage (CV) modes during battery charging. To address these challenges, various primary‐side control techniques, such as asymmetric clamped mode (ACM), asymmetric duty cycle (ADC), and phase‐shift (PS) fixed frequency control strategies, have been proposed for WPT systems. This paper conducts a comparative analysis of these control methods, considering their output voltage ranges and their ability to maintain zero‐voltage switching (ZVS) for the entire control range. Furthermore, the paper presents a generalized design for reduced‐order small signal modelling, utilizing an extended describing function. The designed controller, based on small signal modelling, will undergo real‐time testing to evaluate its dynamic performance in the series‐series resonant converter.

A statistical analysis of a fuel injection rate waveform by the bosch method according to a piezoelectric injector driving pattern

To drive a diesel piezo injector, the charge and discharge of the current supplied to the piezo stack in the injector are controlled as a pair. The charge and discharge currents expand and contract the piezo stack, respectively. The expansion of the piezo stack causes an increase in the hydraulic pressure that presses the top of the injector needle, which results in the fuel injection. In contrast, the contraction of the piezo stack stops the fuel injection. The charge and discharge currents are controlled by a peak and hold method. The hold current is controlled by PWM (pulse width modulation) control of the driving power supplied to the injector. The duty ratios of the PWM signal used for the hold current control are 10%, 30%, and 100%. The injector driving voltage was 140V. A variety of charge and discharge current waveforms were generated by combining the duty ratio control of the PWM waveform with the driving power source. To measure the time-resolved injected mass under various current waveform conditions, the Bosch method was used in this study. An uncertainty analysis was performed on the Bosch injection rate waveform when it was measured 40 times for each fuel injection condition.

15‐4: Improvement of Gradation and Color Shift in Dark Luminance Area with Signal Correction for OLED displays

In recent years, OLED displays have been widely used in smartphones, in‐vehicle displays, and so on. Such applications require a dimming function that responds to external ambient light. It is also necessary to achieve precise gradation and color reproducibility in low luminance levels in dark environments. In this paper, we address two problems of gradation collapse in low luminance levels during low luminance dimming using PWM‐ driven duty ratio control, and color shift due to current leakage between sub‐pixels. In addition, we propose a correction method for improving gradation reproducibility and color reproducibility, using luminance correction.

신재생 에너지용 비대칭 구조의 배전압 회로를 지닌 넓은 입력 전압 범위에서 동작하는 공진형 DC-DC 컨버터

Recently, the demand for renewable energy generation has increased due to environmental pollution and energy depletion. In particular, solar power generation is widely used because of its low maintenance costs and lack of noise. However, given that photovoltaic power generation changes its power voltage depending on weather conditions and panel conditions, a DC–DC converter operating in a wide input voltage range is required to convert to a constant and high DC voltage. Therefore, in this study, the existing secondary symmetric double voltage circuit is asymmetrically configured to reduce switching loss while maintaining a small number of active devices. A constant voltage can also be output through duty ratio control of the secondary switch. Finally, we present a resonant DC–DC converter circuit and modulation technique with high efficiency and high power density in a wide input voltage range. The validity of the proposed circuit and modulation technique is verified through PSIM simulation and 300 [W] test-bed experiment.

Characteristic Analysis of Cascading-Combination DC/DC Controlled-Source Circuit for Marine Electromagnetic Transmitter

Nowadays marine electromagnetic method is a geophysical method which can effectively explore natural gas hydrate (NGH) resources. This method acquires seafloor structure and distribution laws of mineral resources by transmitting high-power electromagnetic waves to the seafloor, and its detection depth relies on intensity of transmitted electromagnetic waves. At present, marine electromagnetic transmitter is inappropriate for transmission of high-power electromagnetic waves, and therefore, a novel DC/DC controlled-source circuit formed by input-series and output-parallel ZVZCS DC/DC controlled-source circuit units was proposed in this paper, and thus transformation of high-voltage and high-power electric energy was realized by using switching devices with low rated voltage and rated current. Common duty ratio control is adopted to construct small-signal mathematical model of cascading-combination ZVZCS DC/DC controlled-source circuit, influences of parameters on voltage balance at input side and current balance at output side are analyzed. Simulation and experimental results verify that the proposed circuit has favorable voltage and current sharing effect and could satisfy deep exploration requirements of marine electromagnetic transmitter with high transmission voltage.

A Closed-Loop High-Frequency Current Shaping Method to Achieve Trapezoidal Transformer Current in a Current-Fed Dual Active Half-Bridge Converter for Minimum RMS Current and Wide-Range ZVS

This article proposes the use of primary and secondary side duty ratio control along with the phase shift control in a current-fed dual active half-bridge (DAHB) converter to achieve trapezoidal transformer current, which results in zero voltage switching (ZVS) of all the switches and minimum rms current even at light loads, for a wide range of input voltage. The high-frequency transformer current is directly sensed at specific transition instants by a delay-adjusted sampling strategy to be used as control variables in a current control structure. This is better because the voltage control of capacitor voltages would have required more expensive sensors. A simple and accurate small-signal model of the converter is developed, and the relevant transfer functions are derived. The controller design details are provided. Finally, experimental results on a 1-kW laboratory prototype demonstrate the effectiveness of the closed-loop duty ratio control in achieving trapezoidal transformer current resulting in improved efficiency and ZVS of the switches, compared to a simple phase shift control.

Solar PV fed FSVSI based Variable Speed IM Drive using ASVM Technique

This research article discloses a solar photovoltaic (SPV) fed 3-φ induction motor (IM) drive aimed at water pumping applications using a three-phase four-switch voltage source inverter (FSVSI). The inverter used has a lower number of switches, reduced gate driver circuits, less switching losses, and is less costly than the orthodox six-switch voltage source inverters (SVSI). Here, the overall system consists of two power conditioning units for duty ratio control of the DC-DC boost converter and a 3-φ FSVSI for controlling and power conversion of DC/AC at a desired level. Moreover, using a boost converter and the P&O maximum power point tracking (MPPT) algorithm, the maximum power is extracted from the SPV system. The indirect vector control (IDVC) is utilized for the IM to provide effective speed control. The SPV system output power depends upon solar irradiation. Hence, the DC voltage and currents vary according to the irradiation. Here, the constant DC-link voltage is achieved using voltage control of the inverter. The anticipated SPV-fed FSVSI IM operation is executed at different insolation stages in the MATLAB as well as validated experimentally using DSPACE DS-1104.

Short-Circuit Protection for Resonant Switched-Capacitor Converter

Short-circuit protection is critical and indispensable for resonant switched-capacitor converter (RSCC) to improve the reliability. Based on comparison of frequency control, duty ratio control and traditional variable frequency variable duty ration control (VFVDC-I), a novel variable frequency variable duty ratio control (VFVDC-II) is proposed for RSCC to suppress the short-circuit current. By analyzing the operation principle and short-circuit mechanism, the RSCC steady-state characteristics as well as the soft switching conditions under four methods are discussed. Then, the resonant characteristics of four methods are compared through state trajectory analysis. At last, the experiments are carried out to verify the correctness of theoretical analysis and feasibility of proposal method. The experimental results demonstrate that the proposed VFVDC-II avoids the voltage oscillation caused by narrow pulse and achieves the shortest transient response and the lowest peak resonant current at short circuit. Moreover, zero voltage switching is realized during turning on, which helps reduce the switching loss.

Duty ratio control technique with torque ripple minimization for induction motor-based electric vehicle applications

Duty ratio control technique with torque ripple minimization for induction motor-based electric vehicle applications

Adaptive shoot-through duty ratio control methodology of stand-alone quasi Z-source inverter

This paper presents an adaptive shoot-through duty ratio control methodology for a stand-alone three-phase quasi-Z-source inverter (qZSI). In practice, variable active and reactive load powers must be met by a qZSI-based stand-alone system. In this context, existing shoot-through control schemes for qZSI adjust the capacitor voltage or DC-link voltage at a fixed reference value. This causes extra voltage stresses on switches, high distortions, and an operating range reduction of the power inverter under variable load demands. On the contrary, the proposed shoot-through control scheme adjusts the shoot-through duty ratio adaptively based on load voltage feedback to improve performances. In this logic, the controllable shoot-through duty ratio facilitates various improved features in comparison to conventional schemes under load power variations. These features include reduced voltage stress across the switches, reduced distortions, and an extended operating range. The suggested proportional-integral (PI)-based scheme has a single control loop with a single measured quantity, i.e., sensing of load voltage only. The proposed concept has been verified via both simulation and experimental studies.

A Simplified DTC-SVPWM Scheme for Induction Motor Drives Using a Single PI Controller

Apart from variable switching frequency, a major issue in direct torque controlled (DTC) induction motor drives is the high torque ripple, which can be minimized by incorporating suitable pulsewidth modulation schemes such as space vector pulsewidth modulation (DTC-SVPWM) and duty ratio control DTC. However, the simplicity and robustness of the DTC scheme are compromised due to the high computational complexity and requirement of a number of motor parameters for the control. In this article, a simple and elegant control algorithm for the realisation of the DTC-SVPWM that is less dependent on motor parameters is proposed. The stator flux-linkage space vector angle needed to generate the reference torque for the DTC operation is computed based on the basic torque equation and the reference stator phase voltage needed for the SVPWM is determined in turn in every sampling period. For the modulation, a carrier-based space vector pulsewidth modulation (CSVPWM) scheme is adopted to get low torque ripple at constant switching frequency. The proposed speed control scheme avoids the use of rotor parameters and rotating reference frame transformations. It requires no sector identification and only one PI controller is needed for the speed control. Though the scheme has comparable torque ripple as that of the conventional DTC-SVPWM scheme, it significantly reduces the computational burden. Hardware results on a three-phase, 2 HP, 415 V induction motor are presented to validate the performance of the proposed control scheme.

A Combinational Sequence Duty Ratio Control of SPV Fed Variable Speed Induction Motor Drive Using Field Oriented Control

This paper emphasizes the performance of solar photovoltaic (SPV) fed field-oriented control (FOC) based induction motor drive (IMD) using combinational sequence (CBS) based duty ratio control (DRC). The low-efficiency problem of SPV panels is resolved with the help of the maximum power point tracking (MPPT) algorithm. Here, the incremental conductance (INC) algorithm and the boost converter extract maximum power from the SPV system. Moreover, the control of IMD is performed using FOC and a 2-level 3-Φ inverter. Furthermore, the reduction voltage/current total harmonic distortion (THD) in IMD is achieved using PWM techniques. Here, the proposed CBS-DRC is a combination of switching sequences in every sector region. However, CBS's operation selects the less area of root mean square (RMS) of stator flux ripples (SFRs) to improve the voltage/current profile of the 3-Φ IMD. Consequently, the reduced torque ripple and speed variations are achieved with the proposed CBS-DRC compared to 0127 sequences. However, the switching sequences are implemented in real-time using the DSPACE DS-1104 controller. Also, a comparison of the overall performance of IMD using 0127 sequence DRC and the proposed CBS-DRC at various loading conditions is disclosed.

Bode diagram based control system design of three phase grid tied photovoltaic systems with Quasi-Z source inverter

In single-stage power conversion, quasi-Z Source inverter (ZSI) provides buck-boost capability and permits shoot through state to enhance the input dc-link voltage. This article discusses the control system design for quasi-ZSI basedthree-phase grid-tied photovoltaic (PV) systems. The inclusion of a low pass filter in the shoot-through duty ratio control loop eliminates ripples in the calculated duty ratio. For tuning the controller gains, an analysis of bode diagrams for the system under consideration is presented. This theoretical analysis is validatedby simulation studies using MATLAB/SIMULINK. The simulation studies reveal that the proposed control system design results in grid code compliant operation of grid-tied PV systems with sinusoidal currents injected at unity power factor. Moreover, PV operation at maximum power point is achieved with good steady-state and dynamic performance.

An improved performance ofPV‐fedIVCinduction motor drive using clamping sequence duty ratio control

An improved performance of<scp>PV</scp>‐fed<scp>IVC</scp>induction motor drive using clamping sequence duty ratio control

An Enhanced Half-Quasi-Z-Source Inverter for Wind Energy Conversion System with D-PMSG

To solve the problem of the traditional quasi-Z-source inverters with low voltage gain, an enhanced half-quasi-Z-source inverter (E-HQZSI) is proposed and applied to direct-drive permanent-magnet wind power generation systems in this paper. The expression of the boosting factor is deduced, which shows that E-HQZSI has higher voltage gain compared with the QZSI and HQZSI. However, the higher voltage gain of the E-HQZSI will lead to the large distortion of the generator stator current necessarily. In this paper, a periodic shoot-through duty ratio control scheme is proposed to reduce the stator current harmonics for E-HQZSI. According to the change rule of the single-phase stator current, the shoot-through duty ratio is compromised to make that the three-phase stator currents are as close as possible to the sine wave. Finally, the correctness of the theoretical analysis is verified by simulation and experiment.

간단한 듀티비 제어 기법에 의한 quasi Z-소스 동적전압보상기

The quasi Z-source dynamic voltage restorer using the conventional switching scheme was able to obtain only the compensation voltage in the out of phase buck-boost mode for voltage swell compensation of the power source and the in-phase boost mode compensation voltage for more than 50% voltage sag compensation. Since this method cannot compensate for the voltage sag of 1-50%, which mainly occurs in industrial fields, a method of connecting additional quasi Z source converter in series and parallel was studied. In this study, a simple duty ratio scheme was proposed which is can be operated as an out of phase buck boost mode to compensate for swell, an in-phase boost mode to compensate for sag of 50% or more and an in-phase buck mode to compensate for sag of 1-50%. In order to prove the validity of this study, PSIM simulation and DSP based experiment were performed. As a result, by the proposed duty ratio control scheme, it was possible to compensate both the in-phase buck boost mode and the out of phase buck boost mode for sag and swell with a single quasi Z-source dynamic voltage compensator. Finally, for each load of 50Ω and 100Ω even if the voltage sag and swell were generated step by step by 10%, the voltage compensation rate remained almost 1, and the THD of the voltage was all good at 5% or less.

Duty ratio control ofthree port isolated bidirectional asymmetrical triple active bridge DC-DC converter

Multiport converters are used in interfacing of distributed energy sources with grid/load. Isolated converters are needed in applications where converter gain is high and there is a requirement of isolation. Dual transformer asymmetric triple active bridge offers the advantage of reduced circulating current. However, the operating range is low for variation in load and source voltage. In this paper duty ratio modulation technique is proposed to regulate the load voltage and control the power flow in both the directions. As a result of the new gating scheme, the converter switches operate with ZVS, irrespective of variations in load power and source voltage. The converter is designed to ensure high switch utilization. The control technique is validatedthrough simulation of a 1kW three port DC-DC converter. It was observerd that the load voltage was regulated for wide range of variation in load power and source port voltages. The single input dual output mode was also verified.

간단한 듀티비 제어에 의한 quasi Z-소스 교류 컨버터의 4상한 전압제어 기법

When controlling the output voltage of a quasi-Z-source AC converter, the conventional switching method can only obtain the output voltage of in-phase boost mode and out-of-phase buck boost mode. Therefore, a cascade connection method of an additional quasi-Z-source AC converter was studied to obtain the in-phase buck voltage required in the industrial field. Since this method uses two converters, the hardware is bulky and there are problems such as resonance. In this study, we propose a simple duty ratio control method that can operate in the in-phase buck mode in addition to the in-phase boost mode and the out of phase buck-boost mode without additional quasi Z source AC converter. To verify the validity of this study, PSIM simulations and experiments were performed. As a result, the proposed method can operate not only in the in-phase boost and out of phase buck-boost modes, but also in the in-phase buck mode, and the output voltage is kept constant in the transient state of a sudden load change. Finally, the input power factor and efficiency are more than 90% in most areas when operating in the in-phase mode, but relatively low in the out of phase mode.

Dynamic control of the pressure-swing distillation process for THF/ethanol/water separation with and without thermal integration

When evaluating the distillation process, it is necessary to consider its economic performance and its controllability. In this study, a strategy was developed to realize the stable control of pressure swing distillation without thermal integration in the face of 20% flow and composition disturbances. Through an exploration of the heat integration between different distillation columns, three partial and one full thermal integration processes were developed. The robust control of these processes was realized by adding reboiler heat duty and feed ratio (Q/F) control structures. Finally, the three processes were compared in terms of control and economy, and it was found that the controllability of the full thermal integration process was slightly inferior to that of the pressure swing distillation without thermal integration. However, the full thermal integration process consumed 29.48% less energy compared to process without thermal integration and resisted ±20% flow and composition disturbances. This research has a certain reference and guiding significance for the process design and control strategy design of triple column swing pressure distillation in industry.

Optimal Sliding Mode Control of Permanent Magnet Direct Drive Linear Generator for Grid-Connected Wave Energy Conversion

the key goal of this article is on the design and optimum sliding mode control for Grid-Connected direct drive extraction method of ocean wave energy by Multi-Objective Particle Swarm Optimization (MOPSO). A Linear Permanent Magnet Generator simulates the ocean wave energy extraction system, driven by an Archimedes Wave Swing. Uncontrolled three-phase rectifiers, a three-level buck-boost converter and 3 level neutral point clamped inverter are planned grid integration of Wave Energy Conversion device. The technique monitors the three-level buck-boost converter service cycle linked to the PMLG output terminals and decides the optimum switching sequence of 3 level neutral point clamped inverter to enable the grid relation. Simulations using Matlab/Simulink were carried out to test working of the wave energy converter after the suggested optimal control method was applied under various operating settings. Various simulation test results indicate that the proposed optimum control system is tested in both normal and irregular ocean waves. And it has been shown that the control method of the MOPSO sliding mode is ideal for maximizing energy transfer efficiency. Better voltage management at the DC-link and for achieving greater controllability spectrum was accomplished by the proposed Duty-ratio optimal control system.