- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
PWM as a Low Cost Method for the Analog Control of MEMS Devices
摘要： In this paper, we discuss the use of pulse width modulation (PWM) to control analog MEMS devices. We achieve a precise linear analog control of MEMS by applying PWM signal with a frequency well above the system’s mechanical natural frequency. We first demonstrate this using a parallel plate actuator and comb-drive, and then extend the technique to control a commercial deformable mirror. Such an approach allows the system designer to replace expensive drive electronics such as the high precision DACs and high voltage, linear amplifiers with a simple on-off switch. The advancements in the electronics industry tend to make precise timing cheaper and faster; our approach exploits these long-term trends to create low-cost control circuits. We also show how PWM control can linearize the positional response of the devices, where typically the position would depend quadratically on the applied analog voltage.
关键词： linearize,pulse width modulation,Microelectromechanical systems,electrostatic actuator
更新于2025-09-23 15:22:29
-
[IEEE 2018 IEEE 6th Workshop on Advances in Information, Electronic and Electrical Engineering (AIEEE) - Vilnius, Lithuania (2018.11.8-2018.11.10)] 2018 IEEE 6th Workshop on Advances in Information, Electronic and Electrical Engineering (AIEEE) - 18-pulse Rectifier with Electronic Phase Shifting with Autotransformer in Inverter and Rectifier Mode
摘要： To reduce harmonic distortion of the input current, multipulse rectifiers are used. They require the presence of phase-shifting transformers or autotransformers. Elimination of electromagnetic phase-shifting devices while maintaining small harmonic distortion of the input current and obtaining a power factor close to unity is possible with the use of electronic phase shift. The electronic phase shift is realized by means of the rectifier itself: the introduction of positive and negative control angles in the pairs of rectifiers’ modules. At present, 12-pulse rectifiers with electronic phase shift are known. Unlike classic rectifiers, they do not use phase-shifting transformers and have a unit power factor. Increasing of the rectifier’s pulse makes it possible to improve the harmonic composition of the input current. The use of the principle of electronic phase shift in 18-pulse rectifier leads to different levels of constant voltage at the output of the rectifiers. In this case, to equalize the currents of rectifiers’ modules, one can use both an increase the voltage at the input of rectifiers operating with large control angles and a decrease the input voltage of the rectifiers operating with smaller control angles. The principles of constructing of matching autotransformers for the 18-pulse rectifier with an electronic phase shift are considered in the article. Comparison of 18-pulse rectifiers with use of step-up and step-down autotransformers is made. Data on the installed capacity of autotransformers, power losses are obtained. The results of thermophysical modeling are presented. When comparing the parameters of the matching magnetic elements, it can be concluded that it is more appropriate to use a step-down autotransformer.
关键词： pulse-width modulation,magnetic elements,electronic phase shifting,rectifiers,power factor
更新于2025-09-23 15:22:29
-
A hybrid output multiport converter for standalone loads and photovoltaic array integration
摘要： Multiport converters (MPCs) are relatively recent power converter structures, which bestow the merits such as the omission of redundant power stages, centralized control, compact packaging, enhanced efficiency, improved reliability, and so on and have larger potential in domestic applications. They have the ability to amalgamate energy sources such as photovoltaic (PV) sources and battery storages, and can accommodate hybrid (ac and dc) domestic loads (bulbs, fans, induction stoves, and electric bike chargers). Hence, they can replace the conventional off-line uninterruptible power supplies, which are habitually used in domestic applications. The unique feature of MPCs is the ability to transfer the power between multiple sources and loads concurrently/independently. This article proposes cascaded sources switched tapping multi-level DC-link inverter (CSSTMLDCLI) involved hybrid loads MPC, which can integrate PV sources and feed above mentioned hybrid domestic loads. The involved novel seven level multilevel inverter structure, the CSSTMLDCLI has reduced component count to offer a high quality ac output, while the dc output is synthesized by a forward converter structure. The working principle of the CSSTMLDCLI along with the systematic design procedure is presented. The validity and effectiveness of the proposed converter are ratified through both MATLAB? Simulink R2016a simulation and the experimentation for a typical solar, battery, and grid supported domestic power backup. The system is managed for a lesser energy purchase using a developed minimal grid usage energy management system, which is implemented using ALTERA QUARTUS II 12.0SP2, field-programmable gate array processor.
关键词： hybrid load MPC (HLMPC),photovoltaic (PV),cascaded sources switched tapping multilevel DC-link inverter (CSSTMLDCLI),multilevel inverters (MLI),pulse width modulation (PWM),multiport converters (MPC)
更新于2025-09-23 15:21:01
-
A High-Power-Factor Dimmable LED Driver with Integrated Boost Converter and Half-Bridge-Topology Converter
摘要： This paper proposes a dimmable light-emitting diode (LED) driver featuring a high power factor and zero-voltage switching on (ZVS). The circuit is obtained by integrating a boost converter and a dc-dc converter with half-bridge topology. The high power factor is achieved by operating the boost converter in discontinuous current mode (DCM). The LEDs are dimmed by the control scheme of asymmetrical pulse-width modulation (ASPWM). The developed circuit eliminates the inherited dc-o?set current of the transformer in a conventional asymmetrical half-bridge converter by introducing a balance capacitor. Both active switches can operate at ZVS by freewheeling the boost inductor current and the transformer magnetizing current to discharge the energy stored in their parasitic capacitance. The circuit operation is analyzed in detailed, and mathematical equations are derived. Finally, a 115-W prototype circuit for driving high brightness LEDs was built and tested. The experimental results verify the feasibility of the proposed LED driver with satisfactory performance. It can achieve a high power factor and ZVS operation.
关键词： power-factor correction,half-bridge converter,zero-voltage switching on (ZVS),asymmetrical pulse-width modulation (ASPWM),light-emitting diode (LED)
更新于2025-09-23 15:21:01
-
[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - New designed electrode patterns on rear side of bifacial PERC solar cells
摘要： Present-day smartphones and tablets demand high audio fidelity (e.g., total harmonic distortion + noise, THD + N < 0.01%), and high noise immunity (e.g., power supply rejection ratio, PSRR > 80 dB) to allow high integration in an SoC. The design of conventional closed-loop pulse width modulation (PWM) Class-D amplifiers (CDAs) typically involves undesirable trade-offs between fidelity (qualified by THD + N), PSRR and switching frequency. In this paper, we propose a fully integrated CMOS CDA that embodies a novel input-modulated carrier generator and a novel phase-error-free PWM modulator, collectively allowing the employment of high loop-gain to achieve high PSRR, yet without compromising linearity/dynamic-range or resorting to high switching frequency. The prototype CDA, realized in 65 nm CMOS, achieves a THD + N of 0.0027% and a power efficiency of 94% when delivering 500 mW to an 8 ? load from VDD = 3.6 V. The PSRR of the prototype CDA is very high, –101 dB @217 Hz and 90 dB @1 kHz, arguably the highest to-date. Furthermore, the switching frequency of the prototype CDA varies from 320 to 420 kHz, potentially reducing the EMI due to spread-spectrum. In addition, the prototype CDA is versatile with a large operating-voltage range, with VDD ranging from rechargeable 1.2 V single battery to standard 3.6 V smart-device supply voltages.
关键词： Audio power amplifiers,power supply rejection ratio (PSRR),total harmonic distortion (THD),pulse width modulation (PWM),class D amplifiers
更新于2025-09-23 15:19:57
-
Communication Compact CRLH Leaky-wave Antenna using TE20 Mode Substrate Integrated Waveguide for Broad Space Radiation Coverage
摘要： This paper introduces a combinational modulation method to be used in classic full-bridge single phase inverters. The proposed method eliminates even-order harmonics at the pulse width modulation (PWM) stage in the control section, unlike the conventional method of even order harmonic cancelation in the power stage, and offers a cost-effective design by switching one leg at high frequency. Using a low-cost digital signal controller platform, a regular sampling technique based on real-time calculation was employed to verify the feasibility of the proposed method on a 500-W single phase voltage source inverter. Performance characteristics, such as switching losses and harmonic distortions, are presented for the new approach and compared with a classic inverter modulation method.
关键词： switching frequency,Combinational logic circuits,inverters,pulse width modulation (PWM),silicon carbide,harmonic distortion
更新于2025-09-23 15:19:57
-
Grid-connected photovoltaic system employing a single-phase T-type cascaded H-bridge inverter
摘要： This paper presents the control and application of a single-phase T-type nine-level cascaded H-Bridge (TCHB) multilevel inverter (MLI) topology. This paper focuses on the effectiveness of the TCHB and its control by presenting the inverter operation based on a PI current controller along with a Maximum Power Point Tracking (MPPT) scheme to realize a grid-tied photovoltaic (PV) system and a novel PWM method offering self-balancing at the DC-link capacitors. In order to attain gating signals for power transistors (IGBTs), the TCHB employs a PWM with one triangular carrier signal and eight reference signals. In addition, a mathematical modelling of the PWM method, along with a theoretical explanation of the self-balancing process has also been provided. To prove the effectiveness of the proposed TCHB topological design, it has been comparatively analysed against other fundamental MLI and symmetric CHB topologies. In addition, to corroborate the working of the control and the PV system application, levels ( ± 2Vdc, ± 2?Vdc, ± Vdc, ± ?Vdc, 0), simulation and hardware results have been presented.
关键词： Nine-level inverter,Pulse Width-Modulation (PWM),Grid-connected,Photovoltaic (PV) system,T-type cascaded H-bridge
更新于2025-09-23 15:19:57
-
Performance Analysis of Mixed Carrier-pulse Width Modulation Scheme
摘要： This study deals with the performance analysis of Pulse Width Modulation (PWM) scheme for three phase voltage source inverter though intermingling of multiple carriers. The proposed PWM scheme using two groups of carriers (inverted Sine wave and Triangle wave), each group having carrier and its 90° shifted. The arbitrary selection of these carriers is based on the linear feedback shift registers value (‘0’ or ‘1’). This random carrier selection is serving to improve the spectral quality of the output of the inverter. This improved waveform has been derived from third harmonic injected sine PWM technique. Simulation results confirm the effectiveness of the proposed scheme in providing very less harmonic noises with minimum distortion and satisfactory fundamental component. This study also shows the implementation compatibility of the work with Field Programmable Gate Array environment.
关键词： Harmonic spread factor,voltage source inverter,linear feedback shift register,random pulse width modulation,pseudo random binary sequence
更新于2025-09-23 15:19:57
-
Spectral-Efficient Reconstructed LACO-OFDM Transmission for Dimming Compatible Visible Light Communications
摘要： Dimming control is critical in practical visible light communication (VLC) systems to satisfy illumination demand. Upon exploiting multiple layers of asymmetrically clipped optical orthogonal frequency division multiplexing (ACO-OFDM) signals for simultaneous transmission, layered ACO-OFDM (LACO-OFDM) constitutes a promising spectral-efficient modulation technique for VLC. However, dimming by integrating the industry-preferred pulse width modulation (PWM) to the LACO-OFDM scheme induces severe clipping noise due to the nonlinearity of LEDs. In this paper, we conceive a reconstructed LACO-OFDM (RLACO-OFDM) scheme incorporating the PWM technique for VLC to accommodate the dimming demands for indoor illumination, while maintaining a spectral-efficient communication link. Moreover, superior to its counterparts, the transmitted symbols in the RLACO-OFDM based VLC system can be readily recovered by a standard LACO-OFDM receiver while no additional detection of the PWM signal is required, which reduces the receiver complexity. Numerical results demonstrate that the proposed RLACO-OFDM is capable of realizing high spectral efficiency over a broad dimming range.
关键词： asymmetrically clipped optical orthogonal frequency division multiplexing (ACO-OFDM),layered ACO-OFDM,pulse width modulation (PWM),Visible light communication (VLC),dimming control
更新于2025-09-19 17:15:36
-
Modern control scheme for Z-Source inverter based PV power generation systems
摘要： Z-source inverter (ZSI) based photovoltaic power conversion system (PV-PCS) provides both the DC link voltage boost and DC-AC inversion in single stage with added features. Traditional maximum power point tracking (MPPT) control algorithm generates the required shoot-through interval to output maximum power to the Z-network. At this instant, the voltage across Z-source capacitor is equal to the MPP voltage of PV array. The capacitor voltage cannot be further increased if it is demanded by the load. This paper presents an improved MPPT control algorithm along with modified MPPT algorithm to achieve both the MPPT as well as capacitor voltage control at the same time. Development and implementation of the proposed algorithm has been carried out by Matlab/Simulink software and the results are provided.
关键词： maximum power point tracking (MPPT),Z-source inverter (ZSI),capacitor voltage control (CVC),pulse width modulation (PWM),photovoltaic array (PVA)
更新于2025-09-19 17:15:36