ABSTRACT:
This study develops a newly designed, patented,
bidirectional dc/dc converter (BDC) that interfaces a main energy storage
(ES1), an auxiliary energy storage (ES2), and dc-bus of different voltage
levels, for application in hybrid electric vehicle systems. The proposed
converter can operate in a step-up mode (i.e., low-voltage
dual-source-powering mode) and a step-down (i.e., high-voltage dc-link
energy-regenerating mode), both with bidirectional power flow control. In
addition, the model can independently control power flow between any two
low-voltage sources (i.e., low-voltage dual-source buck/boost mode).
Herein, the circuit configuration, operation, steady-state analysis, and
closed-loop control of the proposed BDC are discussed according to its three
modes of power transfer. Moreover, the simulation and experimental results for
a 1 kW prototype system are provided to validate the proposed converter.
KEYWORDS:
1. Bidirectional dc/dc
converter (BDC)
2. Dual battery
storage
3. Hybrid electric
vehicle
SOFTWARE: MATLAB/SIMULINK
Fig.
1. Typical functional diagram for a FCV/HEV power system.
Fig.2.
Measured waveforms for low-voltage dual-source-powering mode: (a) gate signals;
(b) output voltage and inductor currents.
Fig.3.
Measured waveforms for high-voltage dc-bus energy-regenerating mode: (a) gate
signals; (b) output voltage and inductor currents.
Fig.
4. Measured waveforms of gate signals, output voltage and inductor currents for
the low-voltage dual-source buck/boost mode: (a) buck mode; (b) boost mode.
Fig.
5. Waveforms of controlled current step change in the low-voltage
dual-source-powering mode: (a) by simulation; and (b) by measurement. (iH is
changed from 0 to 0.85 A; iL1 is changed from 0 to 2.5 A; Time/Div=20
ms/Div
Fig.
6. Waveforms of controlled current step change in the low-voltage dual-source
boost mode: (a) by simulation; and (b) by measurement. (iES1 is changed
from 0 to -6 A; iL2 is changed from 0 to 12 A; Time/Div=20 ms/Div)
Fig.
7. Waveforms of controlled current step change in the low-voltage dual- source
buck mode: (a) by simulation; and (b) by measurement. (iES1 is changed
from 0 to 6 A; iL2 is changed from 0 to 12 A; Time/Div=20 ms/Div)
CONCLUSION:
A
new BDC topology was presented to interface dual battery energy sources and
high-voltage dc bus of different voltage levels. The circuit configuration,
operation principles, analyses, and static voltage gains of the proposed BDC
were discussed on the basis of different modes of power transfer. Simulation
and experimental waveforms for a 1 kW prototype system highlighted the
performance and feasibility of this proposed BDC topology. The highest
conversion efficiencies were 97.25%, 95.32%, 95.76%, and 92.67% for the high-voltage
dc-bus energy-regenerative buck mode, low-voltage dual-source-powering mode,
low-voltage dual-source boost mode (ES2 to ES1), and low-voltage dual-source
buck mode (ES1 to ES2), respectively. The results demonstrate that the proposed
BDC can be successfully applied in FC/HEV systems to produce hybrid power
architecture (has been patented [37]).
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