Pulse Width Modulation Voltage Research Articles

Estimator of the Rotor Temperature of Induction Machine Based on Terminal Voltages and Currents

Monitoring of the rotor temperature is very important for both control and protection of induction machines. Temperature sensors are usually avoided due to additional wiring. Although the best precision is achieved by test-signal-based methods, they are rarely used due to a high-torque ripple. The ripple is negligible in cases where inherent pulse width modulation (PWM) voltage component is used as the test signal. In this paper, a novel temperature estimation method is devised, robust against the PWM delays, signal acquisition delays, and phase errors in high-frequency voltage and current components. Opposed to previous solutions where temperature is calculated based on the real part of the impedance, the presented method is based on the absolute value of the impedance at the PWM frequencies. The temperature is calculated from the change of the input impedance. Proposed method for temperature estimation was tested on an experimental setup which uses an inverter with sine modulated output voltages and an induction servo motor.

永久磁石モータのインピーダンスを用いたキャリア高調波による回転子渦電流損の計算手法

In this paper, an analytical method using the impedance for calculating rotor eddy-current losses caused by inverter carrier harmonics in a permanent magnet motor is investigated. With respect to different types of motors, the accuracy of the proposed method is compared with direct calculation by finite element analysis (FEA) using pulse width modulation (PWM) voltage waveforms. First, the two-phase and three-phase current circuits are investigated for calculation of the impedance. Next, impedance and eddy-current losses of six types of motor are calculated in order to investigate the influences of the motor structure and stator magnetomotive force (MMF) on the rotor eddy-current losses. Because the magnetic saturation of the motor core decreases the accuracy of the calculation, an estimation method is proposed that takes the magnetic saturation into account in order to improve the accuracy. The validity of the proposed method is verified by a comparison with the results of direct calculation by FEA using PWM voltage waveforms. Moreover, the effect of the calculation time reduction obtained by the proposed method is also compared with the case where it is calculated directly by FEA.

Calculation of PM Eddy Current Loss in IPM Machine Under PWM VSI Supply With Combined 2-D FE and Analytical Method

A hybrid method combining 2-D finite-element (FE) method and analytical model is proposed for permanent magnet (PM) eddy current loss calculation in interior PM machines under pulsewidth modulation (PWM) voltage source inverter (VSI) supply, in which the PM eddy current reaction effect and PM axial segmentation are taken into consideration. First, the 2-D time-stepping (TS) FE analysis results considering and neglecting PM eddy current under PWM VSI supply are compared so that the cause of PM eddy current loss, the increase of high-order armature current components due to PM eddy current effect, and the decrease of the high-order components in average flux density due to leakage flux are revealed. Second, an analytical model for PM eddy current loss calculation using voltage input is deduced with the average flux density as input and a leakage flux factor is introduced in the model to meet the real case in PM machine. Moreover, the 3-D frequency FE analysis is used to verify the derived model. Third, the ratio between the average flux density and the imposed flux density is defined as a key parameter to reflect the PM eddy current reaction effect quantitatively, for both 2-D and 3-D cases. A functional relationship is established to describe the variation of the average flux density with and without considering the PM eddy current, where the parameter is obtained with nonlinear fitting of the 2-D FEA results. At last, the calculation procedure of the hybrid method is presented and a flux-concentrating field-modulated PM machine is taken as an example for calculation. The results are verified by an FE analysis. The proposed method is more efficient compared with the 3-D TS FE method while maintaining rather good accuracy.

PWM Harmonic Signature-Based Islanding Detection for a Single-Phase Inverter With PWM Frequency Hopping

Distributed generation (DG) has gained popularity in recent years due to the increasing requirement for renewable power sources. A problem that exists with DG systems is the islanding of DG units that creates safety issues for personnel as well as the potential for damage to utility infrastructure. Therefore, islanding detection methods are utilized to mitigate the risk of islanded operation of DG units. A new passive method of islanding detection based on the signature of the pulse width modulation voltage harmonics is proposed. The viability of the algorithm is investigated with the use of an analytical and time-domain model of the inverter and further validated with experimental results. Furthermore, an extension of the detection scheme is proposed for use in multi-inverter scenarios composed of adaptive frequency hopping to eliminate unwanted tripping.

Multiple criteria for high performance real-time diagnostic of single and multiple open-switch faults in ac-motor drives: Application to IGBT-based voltage source inverter

In this paper, the diagnosis of the open-switch damage in pulse-width modulated voltage source inverter (PWM-VSI) is addressed. The proposed strategy uses multiple normalized diagnostic variables and requires only the measurement of two output inverter currents that were used for a closed-loop control of the electric drive. It consists in analyzing and combining the information provided from the line currents shapes in α-β frame and their normalized mean values, under both healthy and faulty operating conditions. In a first step, twenty-seven patterns built with output inverter currents in α-β axis are used to detect the faulty legs. Six of them are dedicated to the IGBTs single-fault modes and the others to the multiple open-switch modes. A second step is achieved by normalizing the average line currents which allows not only the identification of the single-fault but also makes it possible to distinguish several multiple-fault cases having the same signatures in α-β frame. The proposed technique has the features of simple algorithm, independence of the transient states, single and multiple faults diagnosis, fast fault diagnosis, and being easily included to the existing software without any additional sensors. Experimental results, using a dSpace system with DS1104 controller board based on the digital signal processor (DSP) TMS320F240 and a 3-kW squirrel-cage induction motor drive, are displayed to validate the effectiveness of the proposal.

Measurement and Analysis of Power in Hybrid System

Application with renewable energy sources such as solar cell array, wind turbines, or fuel cells have increased significantly during the past decade. To obtain the clean energy, we are using the hybrid solar-wind power generation. Consumers prefer quality power from suppliers. The quality of power can be measured by using parameters such as voltage sag, harmonic and power factor. To obtain quality power we have different topologies. In our paper we present a new possible topology which improves power quality. This paper presents modeling analysis and design of a pulse width modulation voltage source inverter (PWM-VSI) to be connected between sources, which supplies energy from a hybrid solar wind energy system to the ac grid. The objective of this paper is to show that, with an adequate control, the converter not only can transfer the dc from hybrid solar wind energy system, but also can improve the power factor and quality power of electrical system. Whenever a disturbance occurs on load side, this disturbance can be minimized using open loop and closed loop control systems.

Soft‐switching single‐stage three‐level power amplifier for high‐voltage audio distribution systems

An isolated fully soft-switching single-stage three-level power amplifier (SS3L) based on dual auxiliary networks (DAN) is proposed in this Letter. Compared with the conventional class-D power amplifier, the proposed DAN-SS3L achieves high level of integration without bulky dc link capacitor, and high-efficiency by single-stage conversion and zero voltage switching for all the switches under different operating conditions from light load to full load, which is suitable for high-voltage audio distribution systems. By adopting active auxiliary network, the energy stored in the leakage inductor can be recycled, which eliminates the pulse width modulation voltage spikes. The passive auxiliary network provides enough reactive current for primary-side switches, extending soft-switching range. In addition, commutation overlap strategy is employed to enable natural commutation of bidirectional switches. Experimental results of a 200 W prototype are presented to verify the analysis results.

An Improved Control Strategy for a Four-Leg Grid-Forming Power Converter under Unbalanced Load Conditions

This paper proposes an improved multiloop control strategy for a three-phase four-leg voltage source inverter (VSI) operating with highly unbalanced loads in an autonomous distribution network. The main objective is to balance the output voltages of the four-leg inverter under unbalanced load conditions. The proposed control strategy consists of a proportional-integral (PI) voltage controller and a proportional current loop in each phase. The voltage controller and the current control loop are, respectively, used to regulate the instantaneous output voltage and generate the pulse width modulation (PWM) voltage command with zero steady-state tracking error and fast transient response. A voltage decoupling feedforward path is also used to enhance the system robustness. Since the outer voltage loop operates in the synchronous reference frame, tuning and stability analysis of the PI controller is far from being straightforward. In order to cope with this challenge, the stationary reference frame equivalent of the voltage controller in the rotating frame is derived. Subsequently, a systematic design based on a frequency response approach is provided. Simulation results are also carried out using the DIgSILENT PowerFactory software to verify the effectiveness of the suggested control strategy.

High‐power‐factor dimmable LED driver with low‐frequency pulse‐width modulation

A novel dimmable light-emitting diode (LED) driver is proposed in this study. The circuit topology uses two active switches. One active switch shared by a buck–boost converter and a buck converter is operated at high-switching frequency while the other one is low-frequency pulse-width modulated to dim high-power LEDs. The buck–boost converter plays the role of a power-factor corrector. It operates at discontinuous-conduction mode to waveshape the line current to be sinusoidal and in phase with the input-line voltage. The buck converter regulates the dc-link voltage to output a low-frequency pulse-width modulation (PWM) voltage to drive high-brightness LEDs. Since only one power-conversion process is required, and the buck converter works only when the low-frequency PWM voltage is at a high level, the proposed LED driver has the advantage of high efficiency. Besides, it achieves unity power factor and low total current harmonic distortion.

Eliminated common-mode voltage pulsewidth modulation to reduce output current ripple for multilevel inverters

The paper presents an analysis on the output current ripple in zero common-mode voltage (ZCMV) PWM control of multilevel inverters. The modulation strategy for common-mode voltage (CMV) elimination in multilevel inverters is based on the “three zero common-mode vectors” principle. The space vector diagram, which consists of vectors of ZCMV, is fully explored by properly depicting the base voltage vectors and their corresponding active switching vectors. The switching patterns are limited to those of three switching states each of which is symmetrically distributed. Based on the PWM process simplified to that of a two-level inverter with three allowable switching states and the degree of freedom existing in the switching states arrangement, a novel carrier-based pulsewidth-modulated (PWM) method with optimized output current ripple is proposed. Compared to the existing PWM methods which utilize the same kind of switching patterns, the proposed PWM method has reduced considerably the rms current ripple and total harmonic distortion (THD) of the output current in a wide region of the modulation index. The effectiveness of the proposed method is validated by both simulation and experimental results.

0.18 um CMOS 공정을 이용한 승압형 DC-DC 컨버터 설계

본 논문에서는, 휴대기기를 위한 PWM(Pulse Width Modulation), 전압모드 DC-DC 승압형 컨버터를 제안한다. 제안하는 컨버터는 현재 소형화 되어가고 있는 휴대기기 시장에 적합하도록 1 MHz의 스위칭 주파수를 사용하여 칩 면적을 줄였다. 제안하는 DC-DC 컨버터는 전력단과 제어단으로 이루어지며 전력단은 인덕터, 출력 커패시터, MOS 트랜지스터 등으로 구성되며 제어단은 연산증폭기, 밴드갭 회로, 소프트 스타트 블록, 히스테리시스 비교기와 비겹침 드라이버로 구성된다. 설계된 회로는 히스테리시스 비교기와 논오버랩 드라이버를 사용하여 낮은 전압에서 구동되는 휴대기기의 잡음의 영향을 줄이고 출력전압 리플을 감소시켰다. 제안하는 회로는 1-poly 6-metal CMOS 매그나칩/하이닉스 <TEX>$0.18{\mu}m$</TEX> 공정을 사용하여 레이아웃을 진행하였다. 설계된 컨버터는 입력 전압 3.3 V, 출력전압 5 V, 출력전류 100 mA 출력전압 대비 1%의 출력 전압 리플과 1 MHz의 스위칭 주파수의 특성을 갖는다. 본 논문에서 제안하는 승압형 DC-DC 컨버터는 PDA, 휴대폰, 노트북 등 휴대용 전자기기 시장에 맞는 고효율, 소형화 컨버터로서 유용하게 사용 될 것으로 사료된다. This paper proposes a PWM (Pulse Width Modulation) voltage mode DC-DC step-up converter for portable devices. The converter, which is operated with a 1 MHz switching frequency, is capable of reducing the mounting area of passive devices, such as inductor and capacitor, and is suitable for compact mobile products. This step-up converter consists of a power stage and a control block. The circuit elements of the power stage are an inductor, output capacitor, MOS transistors Meanwhile, control block consist of OPAMP (operational amplifier), BGR (band gap reference), soft-start, hysteresis comparator, and non-overlap driver and some protection circuits (OVP, TSD, UVLO). The hysteresis comparator and non-overlapping drivers reduce the output ripple and the effects of noise to improve safety. The proposed step-up converter was designed and verified in Magnachip/Hynix 0.18um 1-poly, 6-metal CMOS process technology. The output voltage was 5 V with a 3.3 V input voltage, output current of 100 mA, output ripple less than 1% of the output voltage, and a switching frequency of 1 MHz. These designed DC-DC step-up converters could be applied to the Personal Digital Assistants(PDA), cellular Phones, Laptop Computer, etc.

Three-Level PWM Floating H-Bridge Sinewave Power Inverter for High-Voltage and High-Efficiency Applications

This paper presents a topology of a single-phase floating full-bridge three-level pulse width modulation (PWM) power inverter suitable for high-voltage/high-power dc–ac conversion. High power efficiency is obtained thanks to the slow (50/60 Hz) biasing of the H-bridge power supply terminals, allowed by a particular arrangement and control of two complementary active neutral point clamped voltage-source converters. As result, the main PWM switching voltage as well as the maximum drain–source voltage $V_{{\rm DSS}}$ of related transistors are reduced to one-half of the input $V_{DD}$ voltage. This is allowed by the internally generated and accurately balanced middle-node voltage $V_{DD}/2$ . Consequently, advantageous $r_{{\rm DS}({\rm on})}$ of the low-voltage transistors, along with reduced switching PWM voltage result in considerable decreasing of power losses in whole output power range. This paper introduces the main concept of the floating H-bridge topology, and presents in detail the circuit realization. The performances are demonstrated on $450 V_{{\rm DC}}/230 V_{{\rm AC}}$ 2 kW power inverter exhibiting 98.6% peak efficiency and realized in very small $100\times 60\times 30$ mm3 volume.

Hybrid Pulse Width Modulation Strategy for Wide Speed Range in IPMSM with Low Cost Drives

The control performance of hybrid PWM inverter using a phase current measurement is presented in this paper. The hybrid PWM technique consists of space vector pulse width modulation (SVPWM) and six-step voltage control operation. The SVPWM is performed to reduce the harmonic components in the low speed region, and the six-step modulation is applied to increase the maximum speed of the IPMSM in the high speed region. Therefore, it is possible to obtain a great performance in both the low speed range and high speed range. However, the six-step modulation cannot be completely implemented, since the inverter that includes the lag-shunt sensing method has an immeasurable current region. In this paper, a quasi-six-step modulation using a modified voltage vector is proposed. The validity and usefulness of the proposed PWM technique is verified by MATLAB/Simulink and experimental results.

Photovoltaics System for Maximum Output Control

In this thesis, a boost chopper using PV (Photovoltaics) system and PWM (Pulse Width Modulation) voltage type power converter were constructed to provide a pleasant environment to the patients in the hospital wards by controlling temperature, humidity and air-conditioning & heating. For the stable modulation of solar cell, synchronizing signal and control signal were processed using one chip microprocessor. Power converter system was constructed with booster chopper and voltage source inverter and test was carried out for both devices. Constant voltage control method was used to track a maximum power point at boost converter control. For the inverter control, synchronizing signal and control signal were processed by microprocessor for the stable modulation according to the switching theory of SPWM (Sinusoidal Pulse Width Modulation) and directions to each sector. Test was carried out for inverter control using SPWM control method. In addition, grid voltage was detected and this grid voltage and inverter output were operated at the same phase for the phase locking with PWM voltage source inverter so that surplus power could be linked to grid. This characteristic was applied on the temperature and humidity sensors in the general buildings and buildings having specific purposes such as hospitals. The good dynamic characteristic of inverter could be obtained by these applications. Also, PWM voltage inverter maintains a high power factor and low-frequency harmonic output so that power can be supplied in the load as well as system.

Auto Target Tracking Robot Design Based on Smartphone

This paper describes a robot tracking control design based on a smartphone using a commercial microprocessor. The system hardware consists of four major parts: an Android smartphone with an embedded camera, a Microchip microprocessor, a motor driver circuit and an Attacknid robot. First, an image of the surrounding environment is captured by the high definition camera embedded in the smartphone. The target is then recognized from the image using an algorithm developed in Android OS and OpenCV library. Third, motion control and laser activation strategies are achieved using the proposed algorithm implemented in Java. Fourth, the motion commands are delivered to the microchip processor through a USB interface. Finally, the processor produces a pulse width modulation (PWM) voltage to control the robot’s motion and activate the laser diode according commands sent from the smart phone. Experimental results demonstrate the feasibility of this proposed architecture.

Dual mode modulation method for the full‐bridge converter operating in a wide input voltage range

To improve the efficiency of full-bridge converter operating under wide input voltage conditions, this Letter proposes a dual mode modulation method. The full-bridge converter is controlled by phase-shifted mode at low input voltage and asymmetric pulse width modulation mode at high input voltage. The proposed method can reduce power loss, voltage stress of rectifier and output filter requirement. A 500-W full bridge converter with a 160 to 400 V input voltage range is built to confirm the validity of the proposed dual mode method.

Application of synchronous grid-connected controller in the wind-solar-storage micro grid

Original scientifica paper Recently, there has been an increasing interest in using distributed generators (DG) not only to inject power into the grid, but also to enhance the power quality. In this study, a space voltage pulse width modulation (SVPWM) control method is proposed for a synchronous grid-connected controller in a wind-solar-storage micro grid. This method is based on the appropriate topology of the synchronous controller. The wind-solar-storage micro grid is controlled to reconnect to the grid synchronously while maintance or repair is being completed to the power source equation DG at some point, the voltage difference that exists between DG and both sides of the node, a large and sudden electrical surge when DG is reconnected to the grid. It also affects the normal work of the other DG and power quality of a necessary load, and could even seriously paralyze the whole system. So, the topological structure and control method of the synchronous grid-connected controller are discussed in detail and simulation results are presented. The results demonstrate the effectiveness of the proposed method in the synchronous grid-connected controller for the wind-solar-storage micro grid.

An Efficient High Voltage Level Shifter using Coupling Capacitor for a High Side Buck Converter

We propose an efficient high voltage level shifter for a high side Buck converter driving a light-emitting diode (LED) lamp. The proposed circuit is comprised of a low voltage pulse width modulation (PWM) signal driver, a coupling capacitor, a resistor, and a diode. The proposed method uses a property of a PWM signal. The property is that the signal repeatedly transits between a low and high level at a certain frequency. A low voltage PWM signal is boosted to a high voltage PWM signal through a coupling capacitor using the property of the PWM signal, and the boosted high voltage PWM signal drives a p-channel metal oxide semiconductor (PMOS) transistor on the high side Buck converter. Experimental results show that the proposed level shifter boosts a low voltage (0 to 20 V) PWM signal at 125 kHz to a high voltage (370 to 380 V) PWM signal with a duty ratio of up to 0.9941.

SPACE VECTOR PULSE WIDTH MODULATION OF FOUR-SWITCH VOLTAGE SOURCE INVERTER FEEDING THREE PHASE INDUCTION MOTOR

An analytical model with a new space vector pulse width modulation Voltage source inverter technique method of four-switch three-phase inverter (FSVPWM) feeding induction motor is presented. This paper presents a low cost inverter employing only four switches, four diodes and a split capacitor bank in the dc-link. This work is motivated by the need of an efficient and flexible modulation method, which is optimized with respect to minimum electrical motor torque. The proposed modulation strategy for the four-switch operation has the same symmetry as in a classical six-switches space vector pulse width modulation inverter (SSVPWM). The common mode voltage generated by the four-switch space vector pulse width modulation three-phase converter is evaluated and compared to that provided by the standard six-switch space vector pulse width modulation three-phase inverter. Simulation result are presented to demonstrate the feasibility of the proposed approach.

Improved Protein Transfer Efficiency and Signal Intensity in BlotMan Using Pulse Width Modulation

BlotMan is a protein blotting device that allows generating multiple membranes from a single polyacrylamide gel. To transfer all proteins uniformly with the same efficiency regardless of protein size, BlotMan employs pulse-width-modulated (PWM) voltage that applies a higher average voltage to a larger protein species. BlotMan can be controlled not only by its custom-made interface but also by a smart phone via Bluetooth technology. In this study, we examined effects of PWM signals (50%, 60%, and 80% duty cycle) on transfer efficiency and signal intensity in comparison to a constant voltage signal (100% duty cycle). The result revealed that in response to the same average voltage of 150 V, a lower duty cycle with a higher maximum voltage increased transfer efficiency as well as sharpness of transferred proteins. We validated BlotMan’s capability using a chondrosarcoma cell line (SW1353 cells) and a breast cancer cell line (MDA-MB231 cells) in response to antitumor chemical agents. BlotMan successfully generated 5 membranes from a single gel and detected 5 protein species such as c-Src, eukaryotic translation initiation factor 2 alpha (eIF2), phosphorylated eIF2, lamin B, and actin. Collectively, we demonstrated herein that BlotMan reduces an amount of protein samples by generating multiple membranes from a single gel and improving signal intensity with PWM voltage signals.