scholarly journals Reliability evaluation of buck converter based on thermal analysis

2019 ◽  
pp. 217-227
Keyword(s):  
Thermal Analysis ◽  
Duty Cycle ◽  
Reliability Evaluation ◽  
Buck Converter ◽  
Junction Temperature ◽  
Switching Frequency ◽  
Time To Failure ◽  
Reliability Design ◽  
Insulated Gate Bipolar Transistor ◽  
Power Electronic Circuits

The design, which is based on the concept of reliability, is impressive. In power electronic circuits, the reliability design has been shown to be useful over time. Moreover, power loss in switches and diodes plays a permanent role in reliability assessment. This paper presents a reliability evaluation for a buck converter based on thermal analysis of an insulated-gate bipolar transistor (IGBT) and a diode. The provided thermal analysis is used to determine the switch and diode junction temperature. In this study, the effects of switching frequency and duty cycle are considered as criteria for reliability. A limit of 150°C has been set for over-temperature issues. The simulation of a 12 kW buck converter (duty cycle = 42% and switching frequency = 10 kHz) illustrates that the switch and diode junction temperature are 117.29°C and 122.27°C, respectively. The results show that mean time to failure for the buck converter is 32,973 hours.

scholarly journals A Fusion Algorithm for Online Reliability Evaluation of Microgrid Inverter IGBT

Electronics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1294 ◽  
Author(s):  
Chuankun Wang ◽  
Yigang He ◽  
Chenyuan Wang ◽  
Xiaoxin Wu ◽  
Lie Li
Keyword(s):  
Aging Process ◽  
Short Term Memory ◽  
Coupling Model ◽  
Reliability Evaluation ◽  
Junction Temperature ◽  
Stable Operation ◽  
Practical Case ◽  
Fusion Algorithm ◽  
Insulated Gate Bipolar Transistor ◽  
Damage Degree

Due to the diversity of distributed generation sources, microgrid inverters work under complex and changeable conditions. The core device of inverters, an insulated gate bipolar transistor (IGBT), bears a large amount of thermal stress impact, so its reliability is related to the stable operation of the microgrid. The effect of the IGBT aging process cannot be considered adequately with the existing reliability evaluation methods, which have not yet reached the requirements of online evaluation. This paper proposes a fusion algorithm for online reliability evaluation of microgrid inverter IGBT, which combines condition monitoring and reliability evaluation. Firstly, based on the microgrid inverter topology and IGBT characteristics, an electrothermal coupling model is established to obtain junction temperature data. Secondly, the segmented long short-term memory (LSTM) algorithm is studied, which can accurately predict the aging process of the IGBT and judge the aging state via the limited monitoring data. Then, the parameters of the electrothermal coupling model are corrected according to the aging process. Besides, the fusion algorithm is applied to the practical case. Finally, the data comparison verifies the feasibility of the fusion algorithm, whose cumulative damage degree and estimated life error are 5.10% and 5.83%, respectively.

scholarly journals Efficiency of Synchronous and Asynchronous Buck-Converter at Low Output Current.

2019 ◽  
Vol 27 (2) ◽  
pp. 194-206
Author(s):  
Ismael Khaleel Murad
Keyword(s):  
Duty Cycle ◽  
Buck Converter ◽  
Voltage Regulator ◽  
Switching Frequency ◽  
Output Current ◽  
Load Current ◽  
Small Load ◽  
Step Down ◽  
Conduction Mode ◽  
Continuous Conduction Mode

In this paper both synchronous and asynchronous buck-converter were designed to work in continuous conduction mode “CCM” and to deliver small load current. Then the two topologies were tested in terms of efficiency at small load current by use of  different values of switching frequencies (range from 150 KHz to 1MHz) and three separated values of duty-cycle (0.4, 0.6 and 0.8).   Obtained results turns out that efficiency of both synchronous and asynchronous buck-converter “switching step-down voltage regulator” responds in a negative manner to the increase in the switching frequency. However, this impact is being stronger in synchronous topology because of magnifying effect of losses related to switching frequency compared to those related to conduction when working at small load currents; this behavior makes obtained efficiency of both topologies in convergent levels when they operated to deliver small output current especially when working with higher switching frequencies. Larger duty-cycle can rise up the efficiency of both topologies.

scholarly journals Analysis of the Usefulness Range of the Averaged Electrothermal Model of a Diode–Transistor Switch to Compute the Characteristics of the Boost Converter

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 154
Author(s):  
Paweł Górecki ◽  
Krzysztof Górecki
Keyword(s):  
Integrated Circuit ◽  
Input Voltage ◽  
Boost Converter ◽  
Junction Temperature ◽  
Switching Frequency ◽  
Transistor Switch ◽  
Insulated Gate Bipolar Transistor ◽  
Power Electronics Converters ◽  
Rapid Switching ◽  
Averaged Model

In the design of modern power electronics converters, especially DC-DC converters, circuit-level computer simulations play an important role. This article analyses the accuracy of computations of the boost converter characteristics in the steady state using an electrothermal averaged model of a diode–transistor switch containing an Insulated Gate Bipolar Transistor (IGBT) and a rapid switching diode. This model has a form of a subcircuit for SPICE (Simulation Program with Integrated Circuit Emphasis). The influence of such factors as the switching frequency of the transistor, the duty cycle of the signal controlling the transistor, the input voltage, and the output current of the boost converter on the accuracy of computing the converter output voltage and junction temperature of the IGBT and the diode were analysed. The correctness of the computation results was verified experimentally. Based on the performed computations and measurements, the usefulness range of the model under consideration was determined, and a method of solving selected problems limiting the accuracy of computations of the characteristics of this converter was proposed.

scholarly journals Application of Zero Average Dynamics and Fixed Point Induction Control Techniques to Control the Speed of a DC Motor with a Buck Converter

2020 ◽  
Vol 10 (5) ◽  
pp. 1807 ◽  
Author(s):  
Fredy E. Hoyos ◽  
John E. Candelo-Becerra ◽  
Carlos I. Hoyos Velasco
Keyword(s):  
Fixed Point ◽  
System Dynamics ◽  
Duty Cycle ◽  
Dc Motor ◽  
Buck Converter ◽  
Physical Models ◽  
Switching Frequency ◽  
Dc Motors ◽  
Non Linear ◽  
Non Linear System

Several technological applications require well-designed control systems to induce a desired speed in direct current (DC) motors. Some controllers present saturation in the duty cycle, which generates variable switching frequency and subharmonics. The zero average dynamics and fixed point induction control (ZAD-FPIC) techniques have been shown to reduce these problems; however, little research has been done for DC motors, considering fixed switching frequency, quantization effects, and delays. Therefore, this paper presents the speed control of a DC motor by using a buck converter controlled with the ZAD-FPIC techniques. A fourth-order, non-linear mathematical model is used to describe the system dynamics, which combines electrical and electromechanical physical models. The dynamic response and non-linear system dynamics are studied for different scenarios where the control parameters are changed. Results show that the speed of the motor is successfully controlled when using ZAD-FPIC, with a non-saturated duty cycle presenting fixed switching frequency. Simulation and experimental tests show that the controlled system presents a good performance for different quantization levels, which makes it robust to the resolution for the measurement and type of sensor.

scholarly journals PERANCANGAN BUCK CONVERTER SEBAGAI PENGATURAN LAJU KECEPATAN MOTOR DC PADA GERAK LONGITUDINAL DAN TRANSVERSAL PROTOTYPE OVERHEAD CRANE

TRANSIENT ◽  
2018 ◽  
Vol 7 (1) ◽  
pp. 319
Author(s):  
Iqba Anggiawan ◽  
Tejo Sukmadi ◽  
Mochammad Facta
Keyword(s):  
Duty Cycle ◽  
Buck Converter ◽  
Overhead Crane

Crane merupakan alat pendukung pada bidang industri, dalam penerapannya beban yang ditanggung oleh crane beragam, maka diperlukan sebuah sistem dalam mengatur kecepatan kerja crane untuk menyesuaikan jenis barang yang ditanggung. Dalam penelitian ini dilakukan perancangan prototype overhead crane dengan penggerak motor DC magnet permanen CSD80A1-A yang di dioperasikan oleh buck converter. Pengaturan kecepatan putar motor DC magnet permanen sebagai penggerak  prototype overhead crane dilakukan dengan memvariasikan nilai duty cycle pada buck converter. Prototype overhead crane ini dilakukan pengujian dengan variasi tidak dibebani dan dibebani sebesar 5 kg. Berdasarkan hasil pengukuran buck converter, nilai output terendah terjadi pada gerakan forward transversal tidak dibebani dengan duty cycle 60% yang menghasilkan daya keluaran 7,74 watt, kecepatan putar 76,53 rpm, dan torsi 0,96 Nm. Nilai output tertinggi terjadi pada gerakan forward longitudinal dibebani 5 kg dengan duty cycle 90%, yang menghasilkan daya keluaran 24,79 watt, kecepatan putar 80,59 rpm, dan torsi 2,93 Nm.

scholarly journals Speed control of synchronous machine by changing duty cycle of DC/DC buck converter

AIMS Energy ◽  
2015 ◽  
Vol 3 (4) ◽  
pp. 728-739 ◽  
Author(s):  
Rashid Al Badwawi ◽  
◽  
Mohammad Abusara ◽  
Tapas Mallick
Keyword(s):  
Duty Cycle ◽  
Speed Control ◽  
Synchronous Machine ◽  
Buck Converter

scholarly journals Reduction of total harmonic distortion of three-phase inverter using alternate switching strategy

2021 ◽  
Vol 12 (3) ◽  
pp. 1598
Author(s):  
Nur Arifah Ramli ◽  
Auzani Jidin ◽  
Zulhani Rasin ◽  
Tole Sutikno
Keyword(s):  
Integrated Circuits ◽  
Harmonic Distortion ◽  
Total Harmonic Distortion ◽  
Switching Frequency ◽  
Digital Integrated Circuits ◽  
Switching Strategy ◽  
Insulated Gate Bipolar Transistor ◽  
High Switching Frequency ◽  
Alternate Switching ◽  
Torque Ripples

Alternating current (AC) electrical drives mainly require smaller current (or torque) ripples and lower total harmonic distortion (THD) of voltage for excellent drive performances. Normally, in practice, to achieve these requirements, the inverter needs to be operated at high switching frequency. By operating at high switching frequency, the size of filter can be reduced. However, the inverter which oftenly employs insulated gate bipolar transistor (IGBT) for high power applications cannot be operated at high switching frequency. This is because, the IGBT switching frequency cannot be operated above 50 kHz due to its thermal restrictions. This paper proposes an alternate switching strategy to enable the use of IGBT for operating the inverter at high switching frequency to improve THD performances. In this strategy, each IGBT in a group of switches in the modified inverter circuit will operate the switching frequency at one-fourth of the inverter switching frequency. The alternate switching is implemented using simple analog and digital integrated circuits.

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