Compensation Strategy to Eliminate the Effect of Current Measurement Offsets in Grid-Connected Inverters

Lee, Changhee; Choi, Jong‐Woo

doi:10.6113/jpe.2014.14.2.383

Cited by 9 publications

(4 citation statements)

References 24 publications

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“…A measured current signal contains both scaling and DC offset error when compared with an ideal current signal because of nonlinear features of the current measuring process as seen in Figure 2. Specifically, DC offset error occurs from a transducing process of current into voltage by a current sensor and transformation of the analog signal to digital values by Analog to Digital (A/D) converters [3]. Although scaling error occurs at multiple stages in a current measurement process as shown in Figure 2, scaling error is disregarded in this paper because a single-phase system is not affected by scaling error.…”

Section: Analyzing Effect Of DC Offset Error In Pr Current Controlmentioning

confidence: 99%

“…The phase current of the grid side is measured through the following process: (1) a current sensor; (2) analog signal processing circuits, and (3) analog-digital converter (ADC). During the measurement process of phase current, nonlinear characteristics result in a direct current (DC) offset error [3]. To prevent the DC current component, a line frequency isolation transformer was used in References [4,5], but it is applicable, typically, for three-phase inverters.…”

Section: Introductionmentioning

confidence: 99%

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DC Offset Error Compensation Algorithm for PR Current Control of a Single-Phase Grid-Tied Inverter

Lee

2018

Energies

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In a single-phase grid-tied inverter, the direct current (DC) offset error included in the measured grid side phase current has various causes, such as a non-ideal current sensor, unbalanced power supply of an operational amplifier, and nonlinear features of analog components in interface circuits, etc. If the DC offset error is included in the measured current, it causes the secondary harmonic of fundamental frequency and the DC component in grid phase current which result in degradation of inverter performance. In this paper, a theoretical detection method of the secondary harmonic of the fundamental frequency and a DC component in grid phase current for a proportional-resonant (PR) current control system is introduced. Based on the detection method, an algorithm for compensating DC offset error is also presented for single-phase grid-tied inverters. Simulation results and experimental verification of the DC offset error compensation algorithm are shown in this paper.

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Section: Analyzing Effect Of DC Offset Error In Pr Current Controlmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

DC Offset Error Compensation Algorithm for PR Current Control of a Single-Phase Grid-Tied Inverter

Lee

2018

Energies

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“…Maintaining grid current control in a GCI is important to ensure the stability and resilience of DG and MG systems. A proportional-resonance (PR) controller and a proportional-integral (PI) controller are commonly used to maintain current control in the GCI [7,8], although a sliding mode control, model predictive control, or hysteresis control might also be used [9][10][11]. In ideal circumstances, using a PR control will result in infinite bandwidth at the designated resonance frequency, and as a result it is typical to find PR controls being used in an effort to obtain power quality improvements in a grid system.…”

Section: Introductionmentioning

confidence: 99%

A Current Control Algorithm to Improve Command Tracking Performance and Resilience of a Grid-Connected Inverter

2020

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This paper presents a stationary reference frame grid current control algorithm for a grid-connected inverter (GCI) to improve command tracking performance and resilience in response to disturbances, i.e., a grid voltage incident in a GCI current control system. In the proposed algorithm, disturbance rejection is applied to reduce the overcurrent at the GCI in response to a grid fault. Disturbances to the GCI current control system are estimated using a grid current observer, and the estimate applied to the grid current controller to activate the disturbance rejection. The stationary reference frame current of a GCI system is also controlled to avoid cross-coupling issues at a synchronous reference frame model, reference transformation and dependency to phase locked loop (PLL) performance. However, the phase lead or lag and steady-state response error, which are drawbacks of AC signal control based on stationary reference frame proportional-integral (PI) controller, must be eliminated in order to secure competition with the synchronous reference PI (SRFPI) controller that was mainly used in the GCI system. Hence, to compensate for command tracking the AC current, such as steady-state response error and phase lead or lag, command feedforward control is applied in the proposed control system. The theory behind the proposed GCI current control algorithm is analyzed, and the proposed algorithm is tested via simulation and experimentation.

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“…Current offset errors are commonly compensated by reading the A/D converter repeatedly without current flowing in the wire before the operation of inverter. However, completely compensating for the effects of the thermal drift of the analog devices and the switching noise when the system is actually running is impossible [10]- [12].…”

Section: A Effect Of Offset Errormentioning

confidence: 99%

Compensation of Current Offset Error in Half-Bridge PWM Inverter for Linear Compressor

Kim¹,

Im²,

Kim³

2015

Journal of Power Electronics

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This paper proposes a novel compensation algorithm of current offset error for single-phase linear compressor in home appliances. In a half-bridge inverter, current offset error may cause unbalanced DC-link voltage when the DC-link is comprised of two serially connected capacitors. To compensate the current measurement error, the synchronous reference frame transformation is used for detecting the measurement error. When an offset error occurs in the output current of the half-bridge inverter, the d-axis current has a ripple with frequency equal to the fundamental frequency. With the use of a proportional-resonant controller, the ripple component can be removed, and offset error can be compensated. The proposed compensation method can easily be implemented without much computation and additional hardware circuit. The validity of the proposed algorithm is verified through experimental results.

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Compensation Strategy to Eliminate the Effect of Current Measurement Offsets in Grid-Connected Inverters

Cited by 9 publications

References 24 publications

DC Offset Error Compensation Algorithm for PR Current Control of a Single-Phase Grid-Tied Inverter

DC Offset Error Compensation Algorithm for PR Current Control of a Single-Phase Grid-Tied Inverter

A Current Control Algorithm to Improve Command Tracking Performance and Resilience of a Grid-Connected Inverter

Compensation of Current Offset Error in Half-Bridge PWM Inverter for Linear Compressor

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