Parameter Estimation of a Single-Phase Boost PFC Converter with EMI Filter based on an Optimization Algorithm

This paper proposes an approach to estimate the parameters of an AC-DC boost power factor corrector converter which includes an EMI filter. To this end, once the topology is known, measurements at the input and output terminals of the converter are done to identify the values of the passive elements. The proposed methodology is based on the trust-region nonlinear least squares algorithm to identify the parameters of the converter. The steady-state and the transient signals of the converter at the input/output terminals are acquired non-intrusively without any internal modification of the circuitry. The accuracy of the parameter identification carried out is determined by comparing the estimated values with the actual values provided by the manufacturer, and by contrasting the measured signals with the ones obtained with a simulation model with the estimated values of the parameters. The results presented in this paper prove the accuracy of the proposed approach, which can be extended to other power converters and filters.

Diagnosis and Mitigation of Electromagnetic Interference Generated by a Brushless DC Motor Drive of an Electric Torque Tool

Electrical devices in the consumer markets need to comply with stringent standards for electromagnetic interference (EMI) distortion and electromagnetic compatibility (EMC). This paper presents the results of measurements of electromagnetic interference generated by an electrical drive of an electric torque tool with a brushless DC motor. The measurements were made in accordance with the PN-EN 55014-1:2017-06E standard, in the frequency band of 148 kHz–30 MHz. The results confirmed that the tested drive can meet the requirements defined in this document. Another document, the PN-EN IEC 61000-3-2:2019-04E standard, provides limits for the harmonic content in the current drawn by electrical devices from a single-phase AC line. This paper also presents the results of measurements related to this standard. Harmonics, up to and including the 40th one, were determined and compared with the limits given in the standard for class B devices. The measurement results indicate a need to use an active power factor corrector (PFC) filter. Such a system has been tested by computer simulations. The results confirmed its ability to meet the requirements of relevant standards.

Comparison of the power balance in a Totem-Pole Bridgeless PFC topology with several inrush current limiting strategies

Limiting inrush currents is usually necessary when AC-DC conversion is used to supply DC loads such as battery chargers in particular, it must comply with IEC 61000-3-3. This document discusses the suitability of an active inrush current limiter that can be used to replace traditional thermistors and NTC relays. This strategy is based on the control of the phase shift of thyristor type power components. It has been implemented in a totem-pole bridgeless power factor corrector (PFC). Experimental results show that this solution differs from traditional solutions to ensure high energy efficiency (higher than 95%) while limiting inrush currents.

Full Digital Control of an All-Si On-Board Charger Operating in Discontinuous Conduction Mode

This paper deals with the design, tuning and implementation of a digital controller for an all-Si electric vehicle (EV) on-board battery charger operated in discontinuous conduction mode (DCM). This charger consists of two cascaded conversion stages: a front-end power factor corrector (PFC) with two interleaved legs and an isolated phase-shifted full bridge DC/DC converter. Both stages operate in DCM over the complete battery charging power range, allowing lower inductance values for both the PFC and the DC/DC filtering elements. Moreover, DCM operation ensures a large reduction of the reverse-recovery losses in the power diodes, enabling the adoption of relatively cheap Si devices. The main goal of the work is to address the well-known DCM control challenges, leveraging a novel control strategy for both converter stages. This control scheme counteracts the DCM system non-linearities with a proper feed-forward contribution and an open-loop gain adjustment, ensuring consistent dynamical performance over the complete operating range. The designed controllers are tuned analytically, taking into account the delay components related to the digital implementation. Finally, the proposed control strategy is implemented on a single general purpose microcontroller unit (MCU) and its performance is experimentally validated on a 3.3 kW battery charger prototype.

Study of the Influence of Control System Parameters on the Quality of the Input Current of a Three-Phase Power Factor Corrector

The paper suggests a control system of a three-phase power factor corrector. The study of the control system operation is carried out and the expressions for calculating the permissible values of error amplifier factors are obtained. The influence of the error amplifier parameters on phase current quality is investigated. The dependence of total harmonic distortion input current on a combination of error amplifier parameters is obtained at a given value of power factor. The conditions under which the total harmonic distortion input current has the minimum value are found out. This article is of interest to power electronics engineers, who are aimed at developing a three-phase power factor corrector.

Led lamp driver modelling

Currently, there is an increase in the use and production of energy-saving lamps of various types – fluorescent and LED ones. However, it has been found that the use of technologies that have proven themselves in the creation of luminescent sources for LED light sources is ineffective. The use of traditional secondary optics for LED luminaires makes it difficult to create an effective heat sink from LEDs, while the durability of LEDs significantly depends on the heat sink. Another important issue when designing LED luminaires is choosing the right driver. The power consumption of LEDs from the primary network depends on the efficiency of the driver used. The choice of the type of driver also determines the amount of heat that should be removed from its elements. A significant factor influencing the choice of a driver is also the possibility of its operation in conjunction with a voltage regulator – a dimmer, in order to control the illumination. It is also necessary to take into account the IEC recommendations that require manufacturers to use active power factor correctors for devices with switching power supplies and / or electronic ballast with a power of 20 watts or more. Therefore, there is a task of developing a highly efficient driver for use in LED luminaires. In the process of reviewing modern drivers, a driver based on the LT3799 microcircuit from Linear Technology was selected for further research, which is distinguished by high efficiency, working with a large number of produced LEDs, has a built-in active power factor corrector, and allows the use of dimmers. The inclusion of the driver chip recommended by the manufacturer was applied, with the addition of noise suppressing components. The galvanic isolation of the power supply circuits of the LED matrix is provided. Next, the analysis of the characteristics of the selected circuit design solution is carried out using computer simulation. LTSpice EDA was chosen as a modeling tool, which is distinguished by its versatility, ease of use and high reliability of results in comparison with similar software products. The modes of operation are analyzed depending on the requirements for the pulsation of the emitting matrix, the operation of the power factor corrector, and the suppression of interference into the industrial network from the operation of the source is estimated. Various options for the development of the circuitry implementation of the driver based on the LT3799 microcircuit and the operating modes of the most heavily loaded elements are analyzed: an inductor, a key transistor, a damper circuit, a diode in the power supply circuit of an LED matrix. Optimal values of circuit components and parameters of winding elements were selected. It is shown that due to the operation of the power factor corrector, the shape of the current consumption from a sinusoidal voltage source is also almost sinusoidal, which leads to an almost active nature of the load. The modes of operation of the LED matrix for the nominal supply voltage and for the reduced one (with a dimmer) are considered. Methods of implementation of a soft start of an LED matrix are described. Based on the results of the work, conclusions are drawn that summarize the expediency of using the developed driver for an LED device based on the LT3799 microcircuit.

THE USE OF SPECIAL-PURPOSE SIMULATORS AS AN ADVANCED PROFESSIONAL TRAINING TOOL UNDER E-LEARNING CONDITIONS

Traditionally, power electronics has been a complex training field for undergraduate students in the electrical area of the Universidad Distrital Francisco José de Caldas. In this course, multiple theories and concepts are difficult to assimilate due to the distance from other program courses and the complexity of conceptualizing abstract elements. A fundamental learning tool corresponds to the laboratory practices, which allow visualizing concepts, facilitating their understanding and assimilation. However, the mobility restrictions imposed at a global level have prevented access to these learning spaces, restricting fundamental elements of the process, such as direct interaction with circuits and power equipment and critical socialization among students. The effectiveness of the learning process is linked to the resources available, today these resources have been reduced as a result of the social isolation that is expected to continue in the coming months. To reduce this impact, the development of a computer tool has been initiated, capable of replacing the work of students in the laboratory in terms of direct interaction with the circuits, analysis of behavior, and design of applications. The tool is a circuit simulator specifically oriented to the area of power electronics, which is why it is preferable for specific training compared to traditional simulators, since it allows simplifying the behavior of the elements at the switch level, eliminating their parasitic analysis, and therefore reducing the demands on processing capacity, storage memory and simulation time. The first circuit implemented corresponds to an active power factor corrector on a Boost type converter, an application that in itself justifies the use of the tool. As preliminary results, educators have observed increased commitment and motivation of students in their autonomous work.

One Cycle Control of a PWM Rectifier a New Approach

This paper analyzes a Digital Signal Processor (DSP) based One Cycle Control (OCC) strategy for a Power Factor Corrector (PFC) rectifier with Common-mode Voltage (CMV) immunity. It is proposed a strategy that utilizes an emulated-resistance-controller in closed-loop configuration to set the dc-link voltage to achieve unity power factor (UPF). It is shown that if the PFC can achieve UPF condition and if the phase voltage is only affected by CMV, then phase current is free from CMV, as well as a lead-lag compensator (LLC) to average phase current.