Publication: Design and implementation of a 3-phase 2-level inverter with output voltage regulation improvement
Abstract
İnverter çeşitleri, Kesintisiz Güç Kaynakları (KGK), çeşitli motor sürücü uygulamaları ve biyomedikal cihazlar gibi birçok alanda kullanmaktadır. İnverter uygulamalarında en yaygın kullanım alanına sahip topoloji tipi ise Voltaj Kaynaklı İnverter (VKİ) diye de isimlendirebileceğimiz 2-seviyeli inverterlerdir. Birçok uygulamada inverter çıkışındaki voltaj regülasyonunu optimum düzeyde tutmak ve ani değişimlere hızlı tepki vermek hayati önem taşımaktadır. Bu tez çalışması değişken yük koşullarında dahi inverter çıkış voltaj regülasyonunda minimum bozulma ve hızlı toparlanma hedeflenerek yapılmıştır. Bu tez çalışmasında 125 Watt gücünde, şebekeden bağımsız 3-faz bir inverter tasarlanmıştır. Kontrol biriminin tüm kaynak kodu, kaydedici tabanlı programlama ile özgün olarak yazılmıştır. Giriş gerilimi 52V DC, çıkış gerilimi ise 16V AC olarak belirlenmiştir. Sistem, inverter verimi %90 veya üzerinde olacak şekilde tasarlanmıştır. Çalışmada geliştirilen kontrol metodu öncelikle Plecs ve Simulink programları kullanılarak simule edilmiştir. Ardından, algoritma STM32G431RB işlemcisi üzerinde kodlanarak tasarlanan donanım üzerinde gerçeklenmiştir. Çalışmada geliştirilen metot, her bir kesme periyodunda, ADC’nin aşırı örnekleme özelliği kullanılarak örneklemlerin elde edildiği bir sistemde, kayan RMS uygulanarak PI kontrol yapılmasına dayanır. Çalışmada yöntemin literatürde sıkça kullanılan bir diğer kontrol tekniği olan klasik RMS voltaj regülasyonu tekniğine göre avantajları da ortaya konulmuştur.
We use inverter types in many areas such as Uninterruptible Power Supplies (UPS), various motor drive applications and biomedical devices. The most accepted topology in inverter applications is 2-level inverters, which is also called Voltage Source Inverter (VMI). In many applications, it is vital to keep the voltage regulation at the inverter output at an optimum level and to react quickly to sudden load changes. This thesis study has been carried out based on the principle of minimum distortion and fast recovery in the inverter output voltage under variable load conditions. In this thesis, an off-grid 3-phase inverter prototype with a power level of 125 watts was designed. The entire source code of the control unit was written originally with register-based programming. The input voltage is determined as 52V DC, and the output voltage is determined as 16V AC. The system is designed to have an efficiency of 90% or above. The control method developed in the study was first tested in simulation environment using Plecs and Simulink software. Then, the control algorithm was implemented on the hardware, using STM32G431RB microcontroller. The method developed in the study relies on applying sliding RMS to perform PI control in a system where all samples are obtained using the oversampling feature of the ADC at each interrupt period. In the study, the advantages of this method over another commonly used control technique in the literature, the classic RMS voltage regulation technique, have also been demonstrated.
We use inverter types in many areas such as Uninterruptible Power Supplies (UPS), various motor drive applications and biomedical devices. The most accepted topology in inverter applications is 2-level inverters, which is also called Voltage Source Inverter (VMI). In many applications, it is vital to keep the voltage regulation at the inverter output at an optimum level and to react quickly to sudden load changes. This thesis study has been carried out based on the principle of minimum distortion and fast recovery in the inverter output voltage under variable load conditions. In this thesis, an off-grid 3-phase inverter prototype with a power level of 125 watts was designed. The entire source code of the control unit was written originally with register-based programming. The input voltage is determined as 52V DC, and the output voltage is determined as 16V AC. The system is designed to have an efficiency of 90% or above. The control method developed in the study was first tested in simulation environment using Plecs and Simulink software. Then, the control algorithm was implemented on the hardware, using STM32G431RB microcontroller. The method developed in the study relies on applying sliding RMS to perform PI control in a system where all samples are obtained using the oversampling feature of the ADC at each interrupt period. In the study, the advantages of this method over another commonly used control technique in the literature, the classic RMS voltage regulation technique, have also been demonstrated.
Description
Keywords
İki seviyeli eviriciler, voltaj kaynaklı eviriciler, RMS voltaj regülasyonu, sinüs DGM, ADC aşırı örnekleme Two-level inverters, voltage source inverters, RMS voltage regulation, sinusoidal PWM, ADC oversampling