Bidirectional Vienna Rectifier Charger for Electric Vehicles
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Solution Overview
Problem
Existing electric accumulator battery chargers are unidirectional, unable to transmit electrical energy from the battery back to the electrical network, limiting their application in energy restitution and requiring separate chargers for recharging and energy supply.
Innovation Solution
A bidirectional electric accumulator battery charger is designed with a Vienna rectifier stage using pulse width modulation and two isolated DC-DC converters, incorporating bidirectional insulated-gate field-effect transistors and additional switches to enable both charging and energy restitution, optimizing the number of transistors for reduced cost and maintaining efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a unidirectional Vienna rectifier charger is used for battery recharging, then the charging efficiency is improved, but the ability to transmit electrical energy back to the network is lost
Solution Approach 1:
The Vienna rectifier circuit is designed to perform multiple functions: it can operate in traditional rectification mode for battery charging and in inverter mode for energy restitution to the grid. The same circuit components (switches, inductors, capacitors) are utilized for both charging and discharging operations, making the charger bidirectional and eliminating the need for separate charging and energy supply equipment.
2Adaptability or versatility
If bidirectional transistors are added to enable energy restitution, then the versatility is improved, but the manufacturing cost increases
Solution Approach 1:
The invention merges the charging and discharging functions into a single integrated circuit architecture. The same power switches (MOSFETs or IGBTs), inductors, and capacitors are used for both battery charging and energy restitution to the grid. This consolidation eliminates the need for separate bidirectional transistors and reduces the overall component count, thereby lowering manufacturing costs while maintaining bidirectional functionality.
3Ease of manufacture
If the number of power transistors is reduced to lower cost, then the manufacturing cost is improved, but the power conversion efficiency deteriorates
Solution Approach 1:
The control system dynamically adjusts the switching patterns of the power transistors based on the operational mode (charging or discharging) and load conditions. By optimizing the pulse width modulation (PWM) signals and switching sequences, the system maintains high power conversion efficiency with fewer transistors, preventing energy losses while reducing component count for cost effectiveness.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The charger efficiently supports both battery recharging and energy restitution, achieving power equality with battery charging capabilities while minimizing manufacturing costs and maintaining high efficiency, suitable for high-power applications like electric motor vehicles.
Implementation Method 1
a power factor correction stage and a DC-DC converter, the power factor correction stage comprising a Vienna rectifier, operating in pulse width modulation
Implementation Method 2
At least two bridge arms of said Vienna rectifier each comprise a single bidirectional insulated-gate field-effect transistor and a diode
Implementation Method 3
a DC-DC converter, the power factor correction stage comprising a Vienna rectifier... converting the DC voltage and the current obtained at the output of the power factor correction stage into voltage/charging current suitable for the battery
Implementation Method 4
for each output terminal P, N of the power factor correction stage, an output capacitor is connected between the corresponding output terminal P, N and the output midpoint M of the stage of power factor correction 3
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to an electrical accumulator battery (5) charger (1) for an electric automotive vehicle, wherein at least two bridge arms (31, 32) of a Vienna rectifier (3) comprise a bidirectional insulated-gate field-effect transistor (312, 322, 334) and a diode (313, 323, 333), which are connected on either side of the midpoint (310, 320) of the corresponding bridge arm (31, 32), while the other bridge arms (33) each comprise two diodes (332, 333) that are connected on either side of the midpoint (330) of the corresponding bridge arm (33); and in that said DC-to-DC converter stage (4) comprises two DC-to-DC conversion devices (41, 42), each being connected at input in parallel with one of said output capacitors (37, 38) of the correction stage of the power factor (3) and at output to the terminals of said battery (5), such that said charger (1) is capable of allowing an electric current to pass from the battery (5) to said electrical network (2).