LiPB Battery SOC Estimation Using Extended Kalman Filter Improved with Variation of Single Dominant Parameter

Windarko, Novie Ayub,Choi, Jae-Ho The Korean Institute of Power Electronics 2012 JOURNAL OF POWER ELECTRONICS Vol.12 No.1

This paper proposes the State-of-charge (SOC) estimator of a LiPB Battery using the Extended Kalman Filter (EKF). EKF can work properly only with an accurate model. Therefore, the high accuracy electrical battery model for EKF state is discussed in this paper, which is focused on high-capacity LiPB batteries. The battery model is extracted from a single cell of LiPB 40Ah, 3.7V. The dynamic behavior of single cell battery is modeled using a bulk capacitance, two series RC networks, and a series resistance. The bulk capacitance voltage represents the Open Circuit Voltage (OCV) of battery and other components represent the transient response of battery voltage. The experimental results show the strong relationship between OCV and SOC without any dependency on the current rates. Therefore, EKF is proposed to work by estimating OCV, and then is converted it to SOC. EKF is tested with the experimental data. To increase the estimation accuracy, EKF is improved with a single dominant varying parameter of bulk capacitance which follows the SOC value. Full region of SOC test is done to verify the effectiveness of EKF algorithm. The test results show the error of estimation can be reduced up to max 5%SOC.

SOC Estimation Based on OCV for NiMH Batteries Using an Improved Takacs Model

Windarko, Novie Ayub,Choi, Jae-Ho The Korean Institute of Power Electronics 2010 JOURNAL OF POWER ELECTRONICS Vol.10 No.2

This paper presents a new method for the estimation of State of Charge (SOC) for NiMH batteries. Among the conventional methods to estimate SOC, Coulomb Counting is widely used, but this method is not precise due to error integration. Another method that has been proposed to estimate SOC is by using a measurement of the Open Circuit Voltage (OCV). This method is found to be a precise one for SOC estimation. In NiMH batteries, the hysteresis characteristic of OCV is very strong compared to other type of batteries. Another characteristic of NiMH battery to be considered is that the OCV of a NiMH battery under discharging mode is lower than it is under charging mode. In this paper, the OCV is modeled by a simple method based on a hyperbolic function which well known as Takacs’s model. The OCV model is then used for SOC estimation. Although the model is simple, the error is within 10%.

LiPB Battery SOC Estimation Using Extended Kalman Filter Improved with Variation of Single Dominant Parameter

Novie Ayub Windarko,Jaeho Choi 전력전자학회 2012 JOURNAL OF POWER ELECTRONICS Vol.12 No.1

This paper proposes the State-of-charge (SOC) estimator of a LiPB Battery using the Extended Kalman Filter (EKF). EKF can work properly only with an accurate model. Therefore, the high accuracy electrical battery model for EKF state is discussed in this paper, which is focused on high-capacity LiPB batteries. The battery model is extracted from a single cell of LiPB 40Ah, 3.7V. The dynamic behavior of single cell battery is modeled using a bulk capacitance, two series RC networks, and a series resistance. The bulk capacitance voltage represents the Open Circuit Voltage (OCV) of battery and other components represent the transient response of battery voltage. The experimental results show the strong relationship between OCV and SOC without any dependency on the current rates. Therefore, EKF is proposed to work by estimating OCV, and then is converted it to SOC. EKF is tested with the experimental data. To increase the estimation accuracy, EKF is improved with a single dominant varying parameter of bulk capacitance which follows the SOC value. Full region of SOC test is done to verify the effectiveness of EKF algorithm. The test results show the error of estimation can be reduced up to max 5%SOC.

Analysis of Decoupling Method in DQ Transform-based for Grid Connected Inverter

Novie Ayub Windarko,Jinmok Lee,Jaeho Choi 대한전기학회 2008 대한전기학회 학술대회 논문집 Vol.2008 No.7(초록집)

SOC Estimation Based on OCV for NiMH Batteries Using an Improved Takacs Model

Novie Ayub Windarko,Jaeho Choi 전력전자학회 2010 JOURNAL OF POWER ELECTRONICS Vol.10 No.2

This paper presents a new method for the estimation of State of Charge (SOC) for NiMH batteries. Among the conventional methods to estimate SOC, Coulomb Counting is widely used, but this method is not precise due to error integration. Another method that has been proposed to estimate SOC is by using a measurement of the Open Circuit Voltage (OCV). This method is found to be a precise one for SOC estimation. In NiMH batteries, the hysteresis characteristic of OCV is very strong compared to other type of batteries. Another characteristic of NiMH battery to be considered is that the OCV of a NiMH battery under discharging mode is lower than it is under charging mode. In this paper, the OCV is modeled by a simple method based on a hyperbolic function which well known as Takacs’s model. The OCV model is then used for SOC estimation. Although the model is simple, the error is within 10%.

OCV modeling for SOC Estimation of NiMH Battery

Novie Ayub Windarko,Jaeho Choi,Deoksu Hyun 전력전자학회 2009 전력전자학술대회 논문집 Vol.2009 No.1

This paper describes about the estimation of State of Charge(SOC) of NiMH Battery. Among the conventional methods to estimate SOC, the Coulomb Counting is widely used so far, but this method is not precise caused by the error integration. As another one, it has been proposed to estimated of SOC using the measurement of the Open Circuit Voltage(OCV). This method is found as a precise one for SOC estimation. OCV hysteresis characteristic of OCV is very strong comparing with other type of batteries. Another characteristic of NiMH battery to be considered is that the OCV of battery under discharging mode is lower than that under charging mode. In this paper, the OCV is modeled by a simlpe model based on hyperbolic function which well known as Takacs's model. The OCV modeling is used for SOC estimation. Althogh the model is simple but the error is within 10%.

Analysis of Proportional Control for Grid Connected Inverter With LCL Filter

Novie Ayub Windarko,Jinmok Lee,Jaeho Choi 전력전자학회 2008 전력전자학술대회 논문집 Vol.- No.-

There are many types of grid-connected inverter controllers; Synchronous Reference Frame (SRF)-based controller is the most popular methods. SRF-based controller is capable for reducing both of zero-steady state error and phase delay. However, SRFbased controller has a complex algorithm to apply in real application such as digital processor. Resonant controller is also reduced zero-steady state error, but its transfer function has a high order. In this paper, a simple proportional control is applied for grid connected inverter with LCL filter. LCL filter is a third order system. Applying a simple proportional controller is not increased the order of closed loop transfer function. By this technique, the single phase model is easily obtained. To reduce steady state error, proportional gain is set as high as possible, but it may produce instability. To compromise between a minimum steady state error and stability, the single phase model is evaluate through Root Locus and Bode diagram. PSIM simulation is used to verify the analysis.

SOC Estimation of LiPB Batteries Using Extended Kalman Filter Based On High Accuracy Electrical Model

Novie Ayub Windarko,Jaeho Choi,Gyo-Bum Chung 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

This paper proposes a SOC (State-of-charge) estimator of batteries using the Extended Kalman Filter (EKF). EKF can work properly only with accurate model. Therefore, this paper includes high accuracy electrical battery model for EKF state. The modeling is focused on high-capacity LiPB batteries. The battery model is extracted from single cell of LiPB 40Ah, 3.7V. The dynamic behavior of single cell battery is modeled using a bulk capacitor, two series RC networks and a series resistance. The voltage in bulk capacitor represents OCV (Open Circuit Voltage) related to SOC value. EKF is employed to estimate the OCV, and then OCV is converted to SOC value. EKF is tested with experiments data obtained by MACCOR battery tester. EKF is improved with single varying parameter of bulk capacitor which follows the SOC value. The test of estimator algorithm is done for full region of SOC. The test results show the error of estimation can reach max 5%SOC at some points.

Design of Gain Controller of Decoupling Control of Grid-connected Inverter with LCL Filter

Novie Ayub Windarko,Jinmok Lee(이진목),Jaeho Choi(최재호) 전력전자학회 2008 전력전자학술대회 논문집 Vol.- No.-

Grid Connected inverter is produced current to deliver power to grid. To provide low THD current, LCL filters is effective to filter high frequency component of current output from inverter. To provide sinusoidal waveform, there are many researchers have been proposed several controllers for grid-connected inverter controllers. Synchronous Reference Frame (SRF)-based controller is the most popular methods. SRF-based controller is capable for reducing both of zero-steady state error and phase delay. But SRF based controller is contained cross-coupling components, which generate some difficulties to analyze. In this paper, SRF based controller is analyzed. By applying decoupling control, cross-coupling component is eliminated and single phase model of the system is obtained. Through this single phase model, gain controller is designed. To reduce steady state error, proportional gain is set as high as possible, but it may produce instability. To compromise between a minimum steady state error and stability, the single phase model is evaluate through Root Locus and Bode diagram. PSIM simulation is used to verify the analysis.

Electric Modeling of NiMH Battery for SOC Estimation Based on OCV

Jaeho Choi, Novie Ayub Windarko 충북대학교 산업과학기술연구소 2009 산업과학기술연구 논문집 Vol.23 No.2

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