Low Voltage High Power Electrified Powertrain
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Solution Overview
Problem
High voltage electrical systems in electrified vehicle powertrains require electrical isolation, increasing costs and complexity, and existing solutions like reduced phases result in increased torque ripple and cogging torque.
Innovation Solution
A low voltage high power electrified powertrain with four or more independent battery modules, each generating a separate low DC voltage less than 60 Volts, eliminating the need for electrical isolation and using a power inverter module to convert these voltages to low AC voltages for the electric motor, reducing component complexity and enabling high power propulsion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high voltage battery systems are used to meet power output demands, then power capability is improved, but electrical isolation requirements increase system complexity and cost
Solution Approach 1:
The battery system is segmented into multiple independent battery modules, each operating at low voltage (below isolation threshold). These modules are connected in parallel to achieve high power output without requiring electrical isolation systems, thus resolving the contradiction between power capability and system complexity
2Power
If battery modules are connected in series to increase voltage, then power capability is improved, but electrical isolation becomes required
Solution Approach 1:
Instead of connecting battery modules in series to increase voltage (conventional approach), the invention inverts the approach by connecting modules in parallel while maintaining low voltage operation. This inversion allows high power delivery through high current capability without triggering electrical isolation requirements
3Device complexity
If reduced phases are used in electric motor, then manufacturing complexity is reduced, but torque ripple and cogging torque increase
Solution Approach 1:
The invention changes the electrical parameters by providing separate low-voltage inputs to each motor phase through independent battery modules. This parameter change allows full three-phase operation with reduced torque ripple while maintaining simplified control architecture, resolving the contradiction between manufacturing complexity and torque quality
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 solution reduces the need for additional components and complexity, allowing for efficient high power propulsion without electrical isolation, increased customization, and enhanced reliability, while maintaining high torque output and efficiency.
Implementation Method 1
a power inverter module to convert these voltages to low AC voltages for the electric motor
Implementation Method 2
The electric motor receives an alternating current that causes the electric motor to rotatably turn to generate the drive torque
Data Source
Figure 1
Figure 2
AI summary
An electrified powertrain includes an electric motor having four or more coils corresponding to four or more AC phases and configured to generate drive torque to propel an electrified vehicle. The electrified powertrain also includes a low voltage electrical system comprising independent battery modules each configured to output a separate low DC voltage, and a power inverter module (PIM) configured to receive each of the separate low DC voltages from the battery modules, generate a separate low AC voltage for each AC phase using all of or fewer than all of the separate low DC voltages, and output the separate low AC voltages to the coils of the electric motor to drive the electric motor to generate the drive torque to propel the electrified vehicle, wherein none of the separate low DC voltages are electrically isolated and none of the separate AC voltages are considered high voltage.