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elkon
March 2014 1An Imtech Marine Company
elkon
June 2019GPECOM
elkon
Design of an H-Bridge
Bidirectional DC–DC
Converter with LCL Filter for
High Power Battery
Applications
Özhan
Atmaca
elkon
March 2014 2An Imtech Marine Company
Background
ÖZHAN ATMACA
Work
2017- Present R&D Engineer (Power Electronic Systems), Elkon Elektrik R&D Department
(Elkon was established in 1980 to design, manufacture, integrate and commission low-voltage
electrical equipment, e-propulsion drive and automation systems for the maritime industry.)
Education
2010 – 2015 Sakarya University, Faculty of Technology, Electrical and Electronics Engineer
2015 – 2018 M.Sc., Sakarya University, Institute of Natural Sciences, Mechatronic Engineering
Thesis Title: Design and Control of Variable Speed Wind Turbines.
Supervisor: Ass. Prof. Dr. Murat Karabacak
2018 – Present M.Sc., Sakarya University of Applied Sciences, Mechatronic Engineering
Supervisor: Ass. Prof. Dr. Murat Karabacak
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elkon
March 2014 3An Imtech Marine Company
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This paper provides an H-Bridge embedded bidirectional DC–DCconverter with LCL filter for high power energy storage applications.
Low current ripple is critical in sensitive electric devices such as batteries,two-stage photovoltaic systems and fuel cells. Unlike, classical DC–DCconverter, the proposed topology uses LCL filter instead of an inputinductance to reduce the battery ripple current.
This study founds potential application to charge/discharge battery inhigh power applications, i.e., electric transportation (fast chargingelectric vehicles, ships) with a pre-defined reference current.
Design of an H-Bridge Bidirectional DC–DC Converter
with LCL Filter for High Power Battery Applications
elkon
March 2014 4An Imtech Marine Company
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DESCRIPTION OF PROPOSED CONVERTER
LCL filter is used instead of L filter in the classical DC-DC converter. In thisway, the total inductance requirement is reduced for a given constraintof a battery ripple current.
Right Half-Plane Zero (RHPZ) analysis is performed for the proposedboost converter as well as for the classical DC-DC converter.
RHPZ leads to a high recoil in the output voltage and avoids increasingthe voltage controller bandwidth, in the classical bi-directional DC-DCconverter.
Also, If the bandwidth is increased beyond the critical limit, instability willoccur. This implies that a sluggish control performance of the outputvoltage is an inevitable result.
elkon
March 2014 5An Imtech Marine Company
DESCRIPTION OF PROPOSED CONVERTER
In the proposed converter, the RHPZ is far from the origin thanks to the LCLfilter. Therefore, it is possible to increase the bandwidth of the voltagecontrol loop much more than the conventional converter with theproposed converter, without causing the instability.
Besides, the proposed topology reduces the output voltage recoil by morethan 75% as compare to the classical DC-DC boost converter.
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elkon
March 2014 6An Imtech Marine Company
THEORETICAL VERIFICATION OF RHPZ OF THE PROPOSED
AND CLASSICAL DC-DC CONVERTER
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Applying the small signal analysis to classical and proposed DC-DC converter, the
following RHPZ analysis is obtained below result.
1. The RHPZ approaches to zero point when the value of load resistance decreases. The
higher the output voltages, the higher the recoil for the constant load resistance.
2. When the duty cycle (D) increases, the RHPZ approaches to the zero point. Therefore,
the recoil at higher D values is higher.
3. The RHPZ approaches to the origin as L increases. In other words, higher inductance
values increase the recoil.
elkon
March 2014 7An Imtech Marine Company
RHPZ Results
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The same equations were found in both converters. But, the differencebetween them is the inductances, L2 = 100 uH in the proposed converterbut L = 14 mH in the classical converter.
Thanks to inductance values selected, the same battery ripple current isobtained for two cases.1. Low battery ripple current.
2. RHPZ is away from zero.
Therefore, as aforementioned it is possible to increase the bandwidth ofthe voltage control loop much more than the classical DC-DC converter.
elkon
March 2014 8An Imtech Marine Company
SIMULATION AND PARAMETERS (MATLAB/SIMULINK)
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Classical DC-DC converter with an open loop control
Power scheme and open loop control of the bidirectional proposed DC-DC converter
Figs. 1 and 2 illustrate the proposed and classical DC-DC converter. For switching, unipolar PWM isemployed to make the switching frequency doubled at the output. This enables LCL filter to performa very better filtering than that with the bipolar PWM.
elkon
March 2014 9An Imtech Marine Company
SIMULATION AND PARAMETERS (MATLAB/SIMULINK)
Parameters Classical DC-DC Amplifier Converter Bidirectional H-Bridge with LCL Filter DC / DC Converter
Output capacity, Cbus 16800 uF, 0.01Ω 16800 uF, 0.01Ω
∆iL (Battery current ripple value) 9 A 9 A
Load resistance 1 Ω 1 Ω
Operations 0 – 0.5 s output voltage 700 V0.5 – 1.5 s output voltage 1000 V1.5 – 2 s output voltage 700 V
0 – 0.5 s output voltage 700 V0.5 – 1.5 s output voltage 1000 V1.5 – 2 s output voltage 700 V
LCL filter --- L1 = L2 = 100 uH, 0.001ΩCf = 1000 uF, 0.01Ω
Classical boost converterinductance
14mH, 0.01Ω ---
Battery voltage 500 V, 0.1Ω 500 V, 0.1Ω
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elkon
March 2014 10An Imtech Marine Company
SIMULATION RESULTS AND DISCUSSION
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Performance of a classical DC-DC converter Performance of H-bridge bidirectional DC-DC converter
with LCL filter
The simulations are performed in the continuous conduction mode considering 1e-6 step time with
ode23tb solver. The input voltage source Vin has assigned a value of 500 V, 1.0 MW power value
and the switching frequency is selected as 2 kHz. The RHPZ analysis is performed in an open
loop operation by changing the duty cycle through step by step. We analyzed for the same
conditions.
elkon
March 2014 11An Imtech Marine Company
Conclusions
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1. A DC-DC H-bridge bi-directional converter with an LCL filter for high power batteryapplications was developed in this paper.
2. The proposed converter shows same average current and/or voltage values in steady-stateas the classical DC-DC converter, while attaining a very low battery ripple current.
3. The proposed converter requires a lesser filter inductance totally, and hence a lessercopper material, because of a benefit from the LCL filter.
4. Thanks to the RHPZ far from the origin, it is very possible to increase the bandwidth ofthe closed loop control system, without leading to the instability.
5. The simulation studies performed; show that the proposed converter is feasible in designand implementation.
6. As a result, the RHPZ analysis is performed for a worse condition and, even in the worstcase approximately 98,0 % reduction in the recoil voltage is achieved.
7. The classic DC-DC converter is not suitable for high-power systems.
elkon
March 2014 12An Imtech Marine Company
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Photos
elkon
March 2014 13An Imtech Marine Company
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Photos
elkon
March 2014 14An Imtech Marine Company
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Photos
elkon
March 2014 15An Imtech Marine Company
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Photos
elkon
March 2014 16An Imtech Marine Company
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Photos
elkon
March 2014 17An Imtech Marine Company
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Photos
elkon
March 2014 18An Imtech Marine Company
Elkon Elektrik San. ve Tic. A.Ş.
Istanbul Anadolu Yakası OSB
1.Sanayi Cad. No:6 34953 Tuzla
Istanbul Turkey
Tel. +90 216 395 66 95
www.elkon-tr.com
THANK YOU
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Özhan ATMACAR&D Engineer
