محمدرضا بنایی

A step-down converter based on buck and buck-boost converters with a loss reduction technique is proposed in this paper. Utilizing non-electrolytic capacitors in the implementation of the proposed converter has resulted in an increase in circuit life and a reduction in weight and volume. This paper compares the proposed converter to other buck converters. To increase the output efficiency of the converter in comparison to other structures, a new method based on determining the working duty-cycles has been employed to reduce the losses of the converter, resulting in an increase in the converter's output efficiency. In order to demonstrate the differences in efficiency between the proposed method and the conventional method, the efficiency of the converter has been calculated using real-world conditions and the output loss results have been compared. In addition, the proposed converter has a common ground with the input source and has a suitable reduction gain. Finally, this converter has been implemented as a PCB and tested with 100 watts of output power.

Genetic engineering as a technology with potential and actual abilities and capacities can play a fundamental role in removing some obstacles in the production of agricultural, industrial, and medical products. But we should not ignore the possible dangers of genetic engineering on human health and the environment. In this regard, various biosafety conventions, protocols, laws, and standards have been developed and approved in the world to provide a solution for the production, trade, and safe use of genetically modified resources. One of these documents is the "Nagoya-Kuala Lumpur" supplementary protocol. The purpose of this research, which was carried out with a descriptive-analytical method, is to express the international responsibility of governments for transboundary damages caused by genetically modified resources with a view to the supplementary protocol of Nagoya-Kuala Lumpur. The findings indicate that the supplementary protocol, as a part of the legal order created in the international law system, can resolve conflicts in that system. As long as the primary commitment of the Supplementary Protocol, i.e. to make a fundamental change in the implementation of the public law approach to liability for biodiversity damage, is realized even while respecting the domestic laws of the members that reflect their specific economic, social, and legal circumstances, the aim of the Protocol is at least This has been achieved and to solve this criticism, we can resort to the existing solutions regarding the interpretation of multilateral environmental agreements.

This article is an introduction of a new topology of current source inverter (CSI) which can be alternatively implemented in low/medium power applications. This configuration is organized from series connected sub-multilevel inverters blocks. The basis of the recommended multilevel topology is the connections of many cell units in a decent scheme with the help of H-bridge inverter. The suggested inverter produces desired DC current levels with the value of positive and negative. In the recommended configuration, the number of DC current sources, switches and the related gate drive circuits in comparison with the traditional multilevel inverters are lowered. Consequently, cost and volume is decreased in the suggested topology. In order to investigate the suggested structure of the multilevel inverter, the simulation and experimental results for a single-phase 7-level inverter are prepared and indicated.

In this study, a forward converter with phased shifted active clamp is presented for the driving of magnetron lamp (4 kV, 300 mA, 1000 ±40 W).The presented converter is of a boost and high-gain type. To reduce the voltage stress, the active clamp structure is used. In addition, using the clamp switch phase shifted method, while the maximum flux density of the transformer core retains power, it is possible to increase the time the main key is turned on. Thus, with the same nucleus, the possibility of increasing power transmission is created. Therefore, in the same power, the volume, weight and price of the core used should be reduced.Also, a series resonance circuit provides soft switching conditions. Maximum and average power supply power is controlled for minimum losses. The power supply delivers about 1 kW with an average power of about 250 W by adjusting the time the converter is enabled. Other advantages of the proposed circuit include simply power circuit, reduction of the number of switching elements and reduction of switching losses. The design results have been simulated and verified by PSCAD software.

This article studies the design of a power modulator for driving a magnetron tube. In this design thepower modulator works with the half-bridge structure, series resonator and phase shift control method.In this scheme, by controlling the switching phase shift,the balance condition of magnetization current issatisfied and the maximum amount of core saturation current is reduced. As a result, the current stress of switches is reduced and switching and core losses are reduced. So, the size, weight and the cost of thecore of the power transformer will reduce. Also, using leakage inductance of the power transformer, the series-resonance circuit is provided soft switching condition is guaranteed. Suggested power modulator,is able to control the peak and average output power with the minimum loss. The maximum power of a microwave oven is about 1000 w and its average power is 250 W which is controlled proportionally to theinverter on-state periods. Other advantages to the proposed design are simplicity of the power circuit,decrease in the number of switching elements, decrease in the switching losses, and decrease in the leakage inductance of the power transformer. The design results have been verified through simulated ofthe PSCAD software and laboratory tests.

In this paper, a novel structure and a control method to improve the performance of inductive heating circuits is proposed. In the presented structure, with the combination of the performance of a half-bridge resonant converter with voltage-boost capability, the reduction in output efficiency at low power and at high power is compensated to an acceptable level. The use of the low number of switches and diodes, the use of the high-quality capacitors with low capacities, good quality of the input current and also high power factor ensures the proper operation of the proposed converter. The switching of high frequency switches in the proposed structure is carried out as soft-switching where resulting in very low switching losses. In this converter, the design of the input filter in order to prevent the effects of electromagnetic interference has been prepared. Finally, to demonstrate the proposed structure operation, the simulation and experimental results are presented.

A novel current source multilevel inverter is introduced in this paper which is an appropriate alternative to be employed for low/medium power applications. the proposed converter is formed basic modules which paralleling these modules increse output current levels and improve quality of injected current to load or grid. in order to validate advantages of proposed converter versus the several multilevel current source inverters, a full comparison is provided. the simulation results shows the good performance of the proposed converter in off grid and grid-connected applications. Also experimental results for single-phase load confirm the practicablity of the proposed converter.

In this paper, a new driving method is presented for a magnetron bulb utilizing a phase-shifted active clamp fly-back converter. The converter is of a booster, isolated and high gain type. The active clamping structure is used to reduce the main transistor’s voltage stress. By controlling the timing of the transistor clamp, the voltage required for the magnetron is adjusted. The main advantage of the proposed method is the simplicity of the control circuit of the magnetron lamp driver. In addition, the proposed method reduces the size, weight and price of the power transformer core. The power transformer leakage inductance has also been developed to provide a soft switching condition while reducing converter losses. The converter presents a maximum power of 1.6 kW with an average power of 400 W, by setting the timing of the activation of the driving circuit. The design results are simulated and verified by PSCAD Simulink software.

One of the most efficient lighting technology is based on light-emitting diodes (LEDs). Common LED drivers with AC-input (50-60Hz) usually require a bulk electrolytic capacitor to decrease low-frequency ripple in the output. However, the critical element that limits the lifespan of the LED driver is the electrolytic capacitor. An isolated off-line LED driver is proposed in this paper, in which the required output capacitance is reduced so that the electrolytic capacitor can be omitted from the driver structure. The driver’s configuration and controlling method provide a high input power factor. Just a single switch and therefore a single controlling IC have been used in the proposed structure. The input power factor correction is implemented utilizing a boost-based method, and a novel structure is introduced for dc/dc conversion section. Power factor correction and dc/dc conversion are performed employing a simplistic and single controlling system. The output current feeding the LEDs is a high frequency pulsating current. Calculations, simulations and experimental waveforms of a laboratory prototype are presented to confirm the validity of the proposed driver.

In some industries applications such as fuel cells, we must use a high voltage gain dc-dc converters for increasing voltage, but, the conventional converters cannot provide the high voltage gain with increasing duty cycle and the converters efficiency is limited by the equivalent series resistances. For this reason, in this paper, a single switch transformerless high step-up dc-dc converter with reduced voltage stress on the semiconductors is proposed. The proposed converter voltage gain is higher than the conventional converters. In this converter, the power switch voltage stress is low which allows to choose lower voltage rating MOSFETs to reduce both switching and conduction losses and Low voltage stress on the diodes allows the use of Schottky rectifiers for alleviating the reverse-recovery current. The proposed converter can be operated in the continuous conduction mode (CCM) and the discontinuous conduction mode (DCM). In this paper, different operation modes of the proposed converter, calculation of the voltage gain, the currents that flow through the components and efficiency are presented. To verify the operation of the proposed converter, simulation results via PSCAD software are provided.

The conventional boost and buck boost converter have low voltage gain. The voltage gain of the conventional converters is limited considering the issues such as parasitic resistance and because of this issues, high step up dc-dc converter must be used. In this paper, new transformerless high step-up buck boost and boost converters with low stress on the switch are proposed.  In this converters only one active switch are used, which makes the control scheme simple as well as reducing the switching power loss. The voltage gain of the proposed converters is higher than the conventional boost and buck boost converters. The proposed converters expand the continues conduction mode (CCM) operation region . Proposed converters have low voltage stress on the  active switch, low conduction loss and high efficiency. The proposed converters can be operated in the continuous conduction mode (CCM) and the discontinuous conduction mode (DCM). In this paper, different operation modes of the proposed converter, calculation of the voltage gain, the currents that flow through the components and efficiency are provided. To prove the correct operation of the proposed converters, simulation results in PSCAD software are provided.

Conventional Off-Line (50-60Hz) light emitting diode (LED) drivers usually need an electrolytic capacitor to reduce power imbalance between ac input and dc output, and to decrease the low-frequency component of the output ripple. However, electrolytic capacitor is the key component which limits the lifespan of LED driver. If a driver uses a pulsating output current, the electrolytic capacitor can be omitted. This paper proposes a high power factor LED driver with high frequency pulsating driving current, in which electrolytic capacitor has omitted from the topology. The driver has two outputs that allow the number of driving LEDs to increase, an LED string will be connected to each output and a single switch is used in series with each LED string, thus the number of switches is equal to the number of outputs. Output and Storage capacitor voltages are sensed and used to implement the control method to regulate the output current. Low cost and high efficiency can be obtained due to the power structure and the proposed control method. Simulations, calculations and experimental results are provided for the proposed circuit.

In some applications that we need a high voltage gain such as the photovoltaic cell and fuel cell, high step up dc-dc converters must be used, but conventional boost converter cannot provide the high voltage gain. For this reason, in this paper, a single switch transformerless high step-up buck boost dc-dc converter with reduced voltage stress on the semiconductors is proposed. The proposed converter has higher voltage gain in step-up mode in comparison with conventional boost and buck-boost converters. Reduced voltage stress on the active switch allows to choose lower voltage rating MOSFETs to reduce both switching and conduction losses. Low voltage stress on the diodes allows the use of Schottky rectifiers for alleviating the reverse-recovery current. The proposed converter can be operated in the continuous conduction mode (CCM) and the discontinuous conduction mode (DCM). In this paper, different operation modes of the proposed converter, calculation of the voltage gain, the currents that flow through the components, efficiency and capacitors voltage ripple are presented. To verify the operation of the proposed converter, simulation results via PSCAD software and experimental results are provided.

In this paper, a new non-isolated transformerless high step up dc-dc converter with low voltage stress on the active switch for photo voltaic converters is proposed. The converter topology is simple, which in its structure only one active switch is used. It makes reducing the switching power loss. The voltage gain of the proposed converter is higher than the conventional boost converter and the proposed converter works in wide rang than conventional converters. Proposed converter has low voltage stress on the power switches and diodes. The reduced voltage stress across the power switch enables the use of a lower conduction loss of switch. The proposed converter can be operated in the continuous conduction mode (CCM) and the discontinuous conduction mode (DCM). In this paper, different operation modes of the proposed converter, calculation of the voltage gain, the currents that flow through the components, efficiency and capacitors voltage ripple are presented. To verify the operation of the proposed converter, simulation results via PSCAD software are provided.

In this paper, a single switch transformerless high step up dc-dc converter with low voltage stress on the power switch for solar energy application is proposed. In the proposed converter only one power switch is used which makes the control scheme simple as well as reducing the switching power loss. The voltage gain of the proposed converter is higher than the conventional boost converter and buck boost converter. The proposed converter has low voltage stress on the power switch which makes reducing the switching power loss. The proposed converter can be operated in the continuous conduction mode (CCM) and the discontinuous conduction mode (DCM). In this paper, different operation modes of the proposed converter, calculation of the voltage gain, the currents that flow through the components, efficiency and capacitors voltage ripple are presented. To verify the operation of the proposed converter, simulation results via PSCAD software and experimental results are provided.

In this paper, a single switch transformerless high step up dc-dc converter with low voltage stress on the active switch is proposed. In this converter only one active switch is used which makes the control scheme simple as well as reducing the switching power loss. The voltage gain of the proposed converter is higher than the conventional boost converter and the proposed converter expands the continues conduction mode (CCM) operation region. The proposed converter has low voltage stress on the active switch which makes reducing the switching power loss. The proposed converter can be operated in the continuous conduction mode (CCM) and the discontinuous conduction mode (DCM). In this paper, different operation modes of the proposed converter, calculation of the voltage gain, the currents that flow through the components, efficiency and capacitors voltage ripple are presented. To verify the operation of the proposed converter, simulation results via PSCAD software and experimental results are provided.

In this paper, a single switch transformerless high step up dc-dc converter with low voltage stress on the switch is proposed. In the proposed converter only one switch is used which makes the control scheme simple as well as reducing the switching power loss. The voltage gain of the proposed converter is higher than the conventional boost converter and buck boost converter and Proposed converter works in wide rang than conventional converters. The proposed converter has low voltage stress on the switch which makes reducing the switching power loss. The proposed converter can be operated in the continuous conduction mode (CCM) and the discontinuous conduction mode (DCM). In this paper, different operation modes of the proposed converter, calculation of the voltage gain, the currents that flow through the components, efficiency and capacitors voltage ripple are presented. To verify the operation of the proposed converter, simulation results via PSCAD software and experimental results are provided.

A novel transformer less high step-up buck–boost dc-dc converter is proposed in this paper. The output voltages of some sources such as fuel cell, photovoltaic are not regulated. Therefore voltage regulation is required to fix the DC-link voltage. Hence, a buck boost DC/DC converter is suitable to regulate the output voltage of these sources. The presented converter voltage gain is higher that of the conventional boost, buck boost, CUK, SEPIC and ZETA converters and high voltage gain can be obtained with a suitable duty cycle. In this converter, only one power switch is utilized. The voltage stress across the power switch and diodes is low. Hence, the low on-state resistance of the power switch can be selected to decrease conduction loss of the switch and improve efficiency. The low voltage stress across the diodes allows the prevent the reverse-recovery current problem. The proposed converter can be operated in the continuous conduction mode (CCM) and the discontinuous conduction mode (DCM). The presented converter has simple structure; therefore the control of the proposed converter will be easy. The principle of operation and the mathematical analyses of the proposed converter are explained. The validity of the presented converter is verified by the experimental results.