Design and analysis of output filter for 3-phase UPS inverter

Ryu, Byoung-Woo; Kim, Jae‐Sik; Choi, Jaeho; Choi, Changho

doi:10.1109/pcc.2002.998095

Cited by 9 publications

(7 citation statements)

References 2 publications

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“…It was shown that the output impedance of the VSI depends mainly on the inductance of the filter coil in the low-frequency range (below the resonant frequency of the output filter). Some authors [33,34] multiply the module of the reactive power in the inductor by the coefficient over unity. In the presented Equations ( 3) and (4) there were no coefficients.…”

Section: The Output Filter Designmentioning

confidence: 99%

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Improving Low-Frequency Digital Control in the Voltage Source Inverter for the UPS System

Rymarski

2024

Electronics

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Today voltage source inverters (VSIs) operate with high switching frequencies (let us assume higher than 50 kHz) owing to the fast Si (Silicon) or SiC (Silicon Carbide) switching transistors. However, there are some applications, e.g., with slower switches (e.g., IGBT—Isolated Gate Bipolar Transistor) or when lower dynamic power losses are required when the switching frequency is low (let us assume about 10 kHz). The resonant frequency of the output filter is usually below 1 kHz. The measurements of Bode plots of the measurement traces of various microprocessor-controlled VSIs show that in this frequency range, the characteristics of these channels can be simply approximated through two or three switching periods delay. For the high switching frequency, it is not noticeable, but for the low frequency it can cause some oscillations in the output voltage. One of the solutions can be to use the predictor of the measured state variables based on the full-state Luenberger observer or the linear Kalman filter. Both solutions will be simulated in MATLAB/Simulink and the chosen one will be tested in the experimental VSI. The research aims to omit delays in the measurement channels for the low switching frequency by using the predictions for the measured state variables and finally increasing the gains of the controller to decrease the output voltage distortions.

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Section: The Output Filter Designmentioning

confidence: 99%

“…The correction process proceeds in a closed loop of filtering to correct the predicted values of state variables. The measurement prediction covariance is now computed (R-measurement noise covariance matrix) (34).…”

Section: Simulation Of the Low Switching Frequency Vsi Control With T...mentioning

confidence: 99%

Improving Low-Frequency Digital Control in the Voltage Source Inverter for the UPS System

Rymarski

2024

Electronics

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“…Calculating the quotient LF/CF is more ambiguous [8,32,35]. One of the solutions is creating the "cost function" Fcost (14) as a sum of absolute values of reactive power in the filter components [8,32,[35][36][37]. However, the reactive power of an inductor is sometimes weighted two-times higher than that of the capacitor [36,37], because the reduced LF value…”

Section: Design Of the Output Filtermentioning

confidence: 99%

“…Calculating the quotient L F /C F is more ambiguous [8,32,35]. One of the solutions is creating the "cost function" F cost (14) as a sum of absolute values of reactive power in the filter components [8,32,[35][36][37]. However, the reactive power of an inductor is sometimes weighted two-times higher than that of the capacitor [36,37], because the reduced L F value decreases the VSI output impedance for the low frequency and improves the VSI dynamic properties.…”

Section: Design Of the Output Filtermentioning

confidence: 99%

Simple Discrete Control of a Single-Phase Voltage Source Inverter in a UPS System for Low Switching Frequency

Rymarski

2023

Energies

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Previous research has shown that the inverter output voltage distortions are higher for low switching frequencies, and it is impossible to increase the controller gains because it will cause oscillations of the output voltage. The main reason is the real frequency domain characteristic of the PWM modulator and measuring traces, which can be modelled as switching periods delays. The thesis of this paper is that by using the control system that takes care of these delays, it is possible to decrease output voltage distortions for the standard loads for relatively low switching frequencies (e.g., 12,800 Hz). The Luenberger observer was implemented in the multi-input-multi-output passivity-based control of the system with the delay, in order to predict the state variables of the inverter. It is shown that state variable prediction is unnecessary for high switching frequencies (e.g., 51,200 Hz). The theory, simulations and breadboard verification, using the inverter model controlled with the real-time interface MicroLabBox, are presented.

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“…Nonetheless, LCL filters increase the complexity of the system, resulting in a more convoluted model slowing down the design procedure. Thanks to the literature, the procedure of how to design the filter parameters according to different criteria is well known [3]. Despite the chosen filter architecture, the IEEE standards on harmonic voltage distortion for electrical systems IEEE Std 519-1992 and IEEE Std 519-2014 need to be fulfilled to ensure a proper MG operation with a THD limit of 5% and limit of 12% THD over a maximum period of 3 s respectively.…”

Section: Introductionmentioning

confidence: 99%

VSI LC filter optimized by a genetic algorithm from connected to island microgrid operation

2021

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In microgrids (MG) with a high penetration of renewable energy sources (RES) power converters are used to regulate the produced energy to a single voltage and frequency reference value across the MG. Adequate incorporation of an LC filter at the output of power electronic devices allows the attenuation of harmful harmonics that can be introduced to the MGs energy bus. By traditional methods, LC filter values can be calculated by means of the power rating, switching frequency, cutoff frequency, and using the bode frequency domain. Nonetheless, in the transition from a connected to an autonomous MG operation, the calculated LC filter can lead to high harmonic injection. As a result, a tuning methodology capable of obtaining the right set of parameters for the LC filter for a transition event can improve the performance of the MG. This work optimizes the LC output parameters with respect to the size of the filter components, the IEEE Std 519-2014, and bandwidth of the filter, within a bounded region of values subjected to performance conditions such as voltage output, and the produced total harmonic distortion (THD) measurements during the transition from a connected to an autonomous operation. In a case study, genetic algorithm optimization is used to obtain the LC filter parameters and compared to a conventional arithmetic methodology to obtain the values of the filter. The optimization results in a set of values that lead to a higher harmonic attenuation after the transition rather than a conventional method using the switching frequency as the main design factor.

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Design and analysis of output filter for 3-phase UPS inverter

Cited by 9 publications

References 2 publications

Improving Low-Frequency Digital Control in the Voltage Source Inverter for the UPS System

Improving Low-Frequency Digital Control in the Voltage Source Inverter for the UPS System

Simple Discrete Control of a Single-Phase Voltage Source Inverter in a UPS System for Low Switching Frequency

VSI LC filter optimized by a genetic algorithm from connected to island microgrid operation

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