PWM Power Research Articles

수배전반용 배터리 충전기의 최적 설계 방안에 관한 연구

This paper proposes a method for the optimal design of a battery charger for a distribution system using a high-frequency PWM power converter to solve the problems of the conventional rectifier-based battery charger for supplying power to the distribution system during a power outage. The proposed battery charger for the distribution system is designed by reviewing the charging time and current according to the battery capacity, thereby reducing the cost of the battery charger system during manufacture and improving charging efficiency owing to the conduction loss of the battery charger during operation. In addition, the proposed battery charger system for the distribution system utilizes a high-frequency power conversion device to minimize the size and volume of the charger system compared with the conventional rectifier-based battery chargers.
 Therefore, in this paper, we propose an optimal design method for the proposed battery charger for the distribution system and verify its feasibility through simulation results.

Nonlinear control of permanent magnet synchronous generators (PMSG) using feedback linearization

This paper presents nonlinear control of permanent magnet synchronous generators using feedback linearization. Permanent-magnet synchronous generators (PMSGs) are commonly used for small variable-speed wind turbines to produce highefficiency, high-reliability, and low-cost wind power generation. To eliminate the effects of nonlinearity caused by magnetic saturation, an input–output feedback linearization technique is applied to design the high-performance nonlinear current controllers. With this nonlinear control scheme, output voltage responses become faster than those in cascade control structures. Thus, the size of the output filter capacitor can be much reduced since fast voltage control is feasible. As with usual PWM power converters, in addition, the input current is regulated in a sinusoidal waveform. The proposed control scheme provides the wind generation system with the maximum efficiency and high dynamic performance.

Models for Stationary Noise Propagation in Multi-sampled PWM Power Electronic Control Systems With Decimation

Models for Stationary Noise Propagation in Multi-sampled PWM Power Electronic Control Systems With Decimation

Difference Between the PWM and Standard DC Power Cycling Tests Based on the Finite-Element Simulation

PWM power cycling, which has complex control strategies and high testing costs, received a lot of attention in recent years due to the test conditions are closer to the application of power modules than standard DC power cycling. Therefore, the root difference of the failure modes and lifetime of IGBT power modules between DC and PWM power cycling is the concern in this paper, based on the finite element simulation. For stimulating the PWM power cycling with high accuracy and fast speed, an IPWM power cycling is proposed and verified by a simple model. Then an electro-thermo-mechanical coupled model of a single chip is established for comparison. Mainly focus on the current distribution, temperature distribution and stress distribution. The current distribution comparison results show no difference while a higher temperature gradient is shown in PWM power cycling due to the additional switching losses. However, the stress distribution results show chip solder layer is still the main failure mechanism both in DC and IPWM power cycling. Therefore, a conclusion can be obtained that there is no difference in failure mechanism and lifetime between DC and PWM power cycling. And the same bond wire failure and similar lifetime of DC and PWM power cycling tests further verify this conclusion.

Neutral-point-clamped inverter based synchronous reluctance motor drive for solar pump application

PurposeIndustrial drives require appropriate control systems for reliable and efficient performance. With synchronous reluctance machines (SynRMs) slowly replacing the most commonly used induction, switched reluctance and permanent magnet machines, it is essential that the drive and its control be properly selected for enhanced performance. But the major drawback of synchronous reluctance motor is the presence of high torque ripple as its design is characterized by large number of variables. The solutions to reduce torque ripple include design modifications, choice of proper power electronic inverter and PWM strategy. But little has been explored about the power electronic inverters suited for synchronous reluctance motor drive to minimize torque ripple inherently by obtaining a more sinusoidal voltage. The purpose of this paper is to elaborate on the potential multilevel inverter topologies applicable to SynRM drives used in solar pumping applications.Design/methodology/approachThe most significant field-oriented control using maximum torque per ampere algorithm for maximizing the torque production is used for the control of SynRM. Simulation results carried out using Matlab/Simulink are presented to justify the choice of inverter and its control technique for SynRM.FindingsThe five-level inverter drive gives lesser core or iron losses in the SynRMin comparison to the three- and two-level inverters due to lower Id current ripple. The five-level inverter reduces the torque ripple of the SynRM significantly in comparison to the three- and two-level inverter fed SynRM drives. The phase disposition-PWM control method used for the inverter shows the least total harmonic distortion (THD) levels in output voltage compared with the other level shifted PWM techniques.Originality/valueAmong the available topologies, a fitting topology is proposed for use for the SynRM drive to have minimal THD, minimal current and torque ripple. Additionally, this paper presents various modulation techniques available for the selected drive system and reports on a suitable technique based on minimal THD of output voltage and hence minimal torque ripple.

A LCCR filter based harmonic suppression method for power quality improvement

As power converters have been widely used in renewable energy generation and motor drive system for the industrial production, the harmonics of output voltage of power converter will seriously affect the system power quality. To improve power quality of the converter, passive filters such as L-type filters, LC-type filters and LCL filters can are used, which have large volume and poor performance under certain conditions. Aiming at reducing the output harmonic characteristics of PWM power converter, this paper analyzes the frequency characteristics of LCCR filter and proposes a new parameterized model of LCCR filter. Based on the parameterized model of LCCR filter, a high-precision parametric design method of LCCR filter with resonance suppression is also presented in this paper. The frequency characteristics of LCCR filter are designed by a set of four-element methods with frequency characteristic parameters, which can eliminate the coupling relationship between the parameters. The frequency characteristics of the LCCR filter can be directly reflected by the defined parameter. The parameterized design method of LCCR filter presented in this paper can reduces the complexity of multi-parameter LCCR filter design, effectively improves the accuracy and rapidity of filter design. Both the analytical and experimental results validate that the LCCR filter can be accurately designed to suppress the harmonics caused by power converters.

Research on Push-Pull Energy Storage PWM Power Drive of High-Power High-Response Proportional Solenoid

As the traditional power drive circuit is difficult to meet the requests of high-power high-frequency proportional solenoid fast drive, this paper proposes a push-pull energy storage PWM power drive circuit. The circuit is equipped with an energy storage module, which releases energy when the proportional solenoid coil is charged, supplements the output of the power supply current, and shortens the arrival time of the steady-state current. When the coil is discharged, it recovers energy and shortens the time for the coil current to return to zero. In this paper, a theoretical model of push-pull energy storage power drive circuit is established, and simulation analysis and experimental verification are carried out for a proportional solenoid coil with rated current of 3.3A and power of 79W. The results show that the push-pull storage PWM power drive has excellent input-output linearity, minimal ripple, and good steady-state current output performance. Compared with the traditional single switch and reverse discharging power drives, the coil charging speed under the push-pull energy storage type power drive is increased by 25%, and the discharge speed is increased by 95% and 45% respectively.

A CMOS Dual-mode DC-DC Converter with a Digital Dual-mode Controller

This paper describes a CMOS dual-mode DC-DC converter with a digital mode controller, which includes PFM controller and PWM controller. The proposed dual mode controller employs 3-bit control circuit to select a number of counts from a 5-bit digital counter, so that the 3-bit control circuit is capable of adjusting the transient boundary load current between PFM mode and PWM mode. The proposed dual-mode DC-DC converter with a digital dual-mode controller was implemented with a 180 nm 1P/6M BCDMOS process. The measurement results demonstrated the wide range of the input voltage from 2.2 V to 5.0 V with a fixed output voltage of 1.2 V with 3-bit digital capability to control boundary current between PFM mode and PWM mode. The proposed DC-DC converter achieved the peak PFM and PWM power efficiencies of 85% and 91 %, respectively, with an output ripple voltage of 12-32 mV at a switching frequency range of 60 kHz to 2.3 MHz and a load current range of 10 mA to 500 mA.

Induction Motor Based Speed and Direction Controller

Induction motors are widely employed in a variety of sectors, from household gadgets to industrial machinery. This mandates the deployment of an effective and safe speed control device. Induction motors may also run in either direction, which is beneficial in a variety of applications. The Induction Motor Speed and Direction Controller Project are designed to regulate the induction motor's speed and direction. Induction motors run on straight AC lines, and the amount of power they receive determines how fast they revolve. Through AC driver circuitry, we may regulate the power of the AC line to change the speed of the induction motor. A microcontroller from the Atmega family is utilized to provide PWM power to an opto-coupler, which drives the TRIAC that supplies power to the induction motor. The microcontroller receives instructions via a mobile phone connection to the system. The mobile phone sends DTMF signals to the system, which the system recognizes and responds to appropriately. A button is used to raise the speed of the induction motor, a button to change direction, and a button to lower the speed of the induction motor, according to the video. On the LCD, the entire procedure may be observed in real time. In this way, this project demonstrates how to control the speed and direction of an induction motor.

Experimental study on the influence of high frequency PWM harmonics on the losses of induction motor

For the purpose of studying the influence of high frequency PWM harmonics on the losses of induction motor, this paper first introduces the latest international standard IEC/TS 60034-2-3 for the separation of the losses and the measurement of the efficiency of induction motor under PWM power supply. Then, considering that the skin effect of windings in induction motors under the condition of PWM power supply more apparent, this paper uses the stator AC resistance to replace the stator DC resistance in the IEC/TS 60034-2-3 standard to obtain more accurate separation results. On this basis, an improved method of loss separation for converter-fed induction motor is proposed by using the accurate time-step finite element method to calculate the rotor copper loss under no-load condition which cannot be considered in IEC/TS 60034-2-3 standard. Finally, this method is used to measure and separate the losses of a 5.5 kW converter-fed motor under different operating conditions. The results show that the loss of induction motor which is driven by PWM converter is obviously greater than that of sinusoidal drive, especially under light load or no load condition. The whole no-load losses of the motor driven by PWM converter increases by more than 20.0% compared with that of the sinusoidal driving condition.

PWM Inverter with 4-Phase Carrier for Grid Connection Via Combined LCL Filter

A PWM power conversion system connected to a grid through parallel-combined LCL filter is proposed in this paper. The system has four inverters paralleled and operates with PWM using 4-phase carrier for powering up and performance improvement. Four LCL filters have four separate filter inductors connected to individual inverters and one common LC filter which is composed of a filter capacitor and a grid inductor. The differential mode current circulates only through four inverters and four filter inductors. The differential mode current is completely eliminated from the filter capacitor and the connected power grid. Accordingly, performance improvement can be achieved since the current in the filter capacitor is reduced and the harmonic current into a grid is reduced. An 1.3kW single phase prototype system has been constructed and tested, and the proposed system has been verified.

Analysis of Buck-Boost Inverter Installed in Permanent Magnet Linear Generator-based Ocean Wave Energy Converter

The direct drive Permanent Magnet Linear Generator (PMLG)-based Ocean Wave Energy Converters (OWECs) produce variable A.C. voltage. In this article, the variable A.C. voltage is converted into a variable D.C. voltage by a standard rectifier. After that, a buck–boost inverter is used to produce constant amplitude A.C. voltage at the load end. The buck–boost inverter, implemented here, operates in three modes: buck, boost, and buck–boost. Furthermore, a switching algorithm is developed to generate reference A.C. voltage. Systematic design of power converter, small-signal analysis, and PWM control strategy are discussed. The simulation results and results from a laboratory prototype are presented to support the theoretical concepts.

Comparison of junction temperature variations of IGBT modules under DC and PWM power cycling test conditions

Comparison of junction temperature variations of IGBT modules under DC and PWM power cycling test conditions

Performance investigation of standalone wind power system equipped with sinusoidal PWM power inverter for household consumer in rural areas of Indonesia

This paper proposes the performance investigation of a standalone wind power system equipped with sinusoidal pulse width modulation (SPWM) power inverter for household consumption in rural areas of Indonesia. Indonesia, which is in the tropics, has the potential for developing wind power plants. One of the potential areas is the South Coast, Bantul, Yogyakarta Special Region, the location of this research. This work has designed, assembled, and tested a 4-kW wind power plant using a permanent magnet synchronous generator (PMSG) driven by a horizontal type of turbine. The test results show that the power plant can generate electrical energy suitable for meeting the electricity needs of residents’ homes. This success indicates that the generator’s voltage is good enough and feasible to be stored in the battery. Although the voltage’s value depends on the wind speed, it is adequate because it is close to the nominal voltage that the PMSG generator should produce. The electrical energy generated by this power plant is stored in the battery bank. Also, the performance of the SPWM power inverter has been demonstrated in the experimental tests of resistive and inductive loading. This power plant’s development follows the government’s commitment to utilizing renewable energy sources as priority energy as a strategy to reduce dependence on fossil energy and overcome the environment.

High Performance Single and Double Loop Digital and Hybrid PID-Type Control for DC/AC Voltage Source Inverters

The concept of hybrid control has been introduced, in which the analog implementation of the control algorithm is combined with a digital algorithm for determining the PWM duty cycle. Single-loop PD and PID control systems are compared to a double-loop architecture with additional capacitor current sensing for both digital and hybrid controller realizations. The performance is measured as the THD value under resistor-capacitor rectifier load. It has been shown that a properly constructed continuous-time model of a digital controller with a PWM power converter behaves like the actual discrete-time system, which allows for a simple controller analysis and design. The role of a PWM type for capacitor current feedback is emphasized. The simulation models of a real inverter are presented, which are used to tune the controllers and to evaluate the control performance for both rectifier and abruptly changing resistive load. The obtained solutions achieve the THD values comparable to the VSI without load. The results are contrasted with the control methods based on resonant filters.

Modeling of Power Electronics Systems and PWM Modulators in Harmonic-State Space

Modeling and simulation of the converter dominated systems have recently emerged as a monumental challenge. These simulations are useful for predicting instability and system's harmonic content, consequently assisting in developing better control and filters. But, as more and more converters are incorporated into the system, time-domain simulation models have a tradeoff of either limited accuracy or fewer simulated converters. On the contrary, frequency-domain modeling methods like linear time-invariant models cannot capture the system's time-varying nature and complex converter interactions. The recently developed harmonic state space (HSS) modeling approach has emerged to provide an alternate avenue to model and simulate these converter-dominated systems. HSS models, while accurate, until recently have not been able to reliably model the non-linear pulse width modulator. This paper solves this challenge and develops a new modulator model for harmonic domain models, including HSS. The proposed large-signal modulator is computationally less demanding and can reliably capture the harmonic spectrum of complex multi-converter systems till converter switching frequencies. Several optimization methods are introduced to utilize the unique multi-harmonic nature of HSS, making simulations faster than conventional time-domain methods. Results are verified with extensive simulations and experiments. The application, challenges, and future scope for this method are also highlighted.

Research On Radial Electromagnetic Force and Vibration Response Characteristics of Squirrel-Cage Induction Motor Fed By PWM Inverter

In order to study the influence of current harmonics generated by PWM inverter on radial electromagnetic force and vibration response of squirrel-cage induction motor, an analysis method is introduced in this paper. Firstly, the relationship among the order and frequency of electromagnetic force wave of the motor under the action of harmonic current is analyzed theoretically. Secondly, a squirrel-cage induction motor is used to build a vibration response analysis model with multiple physical field coupling. The electromagnetic force wave and vibration response spectrum of the motor under sinusoidal power supply and PWM harmonic power supply are obtained. The results show that: for the prototype, the frequency components of 0-order, 2 (2p) order electromagnetic force wave will be introduced when the harmonic current of the inverter is supplied. Finally, the correctness of the analysis method is verified by the vibration experiment of the prototype.

Sampling Rate and Performance of DC/AC Inverters with Digital PID Control—A Case Study

The huge influence of the sampling rate on the performance of the digital PID control of a voltage source inverter (VSI) is revealed. It is shown that an appropriately chosen continuous-time model of a digital controller with the PWM power converter behaves like the actual discrete-time system, which allows for a simple controller analysis and design. The variable structure nature of the inverter with both the RC rectifier and an abruptly changing resistive load with two modes of operation within the sampling period is directly taken into account. Two simulation models, a discrete-time PWM and a continuous-time, of an inverter are presented, which are used to tune the PID controller and to evaluate the control performance. The behavior of the system in both modes is explained on the basis of the root loci and frequency characteristics. The results obtained for three sampling rates: 12.8, 25.6, and 51.2 kHz, are presented and compared with an actual VSI experiment. A comparison with other results obtained for this VSI shows that properly tuned PID control outperforms the more sophisticated solutions based on the coefficient diagram method (CDM) and the passivity based control (PBC).

Application of the hybrid genetic particle swarm algorithm to design the linear quadratic regulator controller for the accelerator power supply

The purpose of this paper is to study a new method to improve the performance of the magnet power supply in the experimental ring of HIRFL-CSR. A hybrid genetic particle swarm optimization algorithm is introduced, and the algorithm is applied to the optimal design of the LQR controller of pulse width modulated power supply. The fitness function of hybrid genetic particle swarm optimization is a multi-objective function, which combined the current and voltage, so that the dynamic performance of the closed-loop system can be better. The hybrid genetic particle swarm algorithm is applied to determine LQR controlling matrices Q and R. The simulation results show that adoption of this method leads to good transient responses, and the computational time is shorter than in the traditional trial and error methods. The results presented in this paper show that the proposed method is robust, efficient and feasible, and the dynamic and static performance of the accelerator PWM power supply has been considerably improved.

Optimized Control for Modified Push-Pull Dual Active Bridge Converter to Achieve Wide ZVS Range and Low Current Stress

Compared with the traditional dual active bridge (DAB) converter, the push-pull DAB converter can reduce the number of switching devices and is suited for low voltage applications. In order to extend the zero voltage switching (ZVS) range and reduce the current stress within wide voltage range, this paper modifies output rectifier circuit, and proposes an optimized control strategies for push-pull DAB converters. Unlike conventional modulation that only utilizing the primary duty cycle and phase shift angle to adjust the power, the duty cycle for the secondary side is also utilized for the PWM modulation. With the modified PWM modulation, a control law for achieving minimum root mean square (RMS) current within the precondition of achieving wide range ZVS is proposed. The working modes under the modified PWM modulation, current and power analysis and optimized control law are analyzed in depth. Finally, the experimental results using a 1 kW prototype verify the effectiveness of the proposed converter.