MOSFET Motor Circuit Selective Energy Supply
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Solution Overview
Problem
Existing motor control systems using electromechanical relays and semiconductor switches are bulky, complex, and inefficient, with high electrical losses and mechanical wear, particularly in AC applications.
Innovation Solution
A circuit design using a single multiphase converter and MOSFETs in each phase line for selective motor control, minimizing electrical losses and complexity by allowing bidirectional current blocking with intrinsic body diodes, and incorporating overvoltage protection and dynamic braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If separate amplifiers are used for each motor in a multi-motor system, then each motor can be controlled independently, but the overall device complexity and cost increase significantly
Solution Approach 1:
A single amplifier is designed to serve multiple motors simultaneously by implementing multi-phase PWM control. The amplifier switches between different motor phases (e.g., Phase A, Phase B, Phase C) within a cycle, allowing one amplifier to replace what would traditionally require three separate amplifiers, thus reducing device complexity while maintaining independent control capability
Solution Approach 2:
The amplifier employs periodic switching between different motor phases using PWM (Pulse Width Modulation) technique. By rapidly switching between phases in a periodic manner within each control cycle, the amplifier can deliver independent control signals to multiple motors through time-division multiplexing, achieving both independence and resource sharing
2Device complexity
If a single amplifier is used to supply multiple motors, then device complexity is reduced, but the amplifier current demand increases and may cause supply voltage dips
Solution Approach 1:
The amplifier uses periodic PWM switching to distribute current demand over time rather than requiring peak current simultaneously for all motors. By switching between phases periodically and controlling duty cycles, the amplifier manages current draw in a time-division manner, reducing instantaneous current demand and preventing voltage dips
Solution Approach 2:
The system dynamically adjusts PWM duty cycle parameters based on motor phase requirements and current supply conditions. By changing the duty cycle parameters periodically and adaptively, the amplifier optimizes current distribution across multiple motors, ensuring stable operation without excessive current demand that would cause voltage drops
3Power
If high current is drawn by the amplifier, then motor power output is sufficient, but voltage dips occur affecting other circuits in the vehicle
Solution Approach 1:
The amplifier implements periodic PWM switching that distributes power delivery over time rather than drawing peak current continuously. This time-division power delivery approach maintains sufficient average motor power output while reducing instantaneous current spikes that cause voltage dips and interfere with other vehicle circuits
Solution Approach 2:
The amplifier acts as an intermediary between the power supply and multiple motors, using PWM control to buffer and regulate current flow. By introducing this control layer, the system can deliver required motor power while smoothing current demand patterns to prevent voltage dips from propagating to other vehicle circuits
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 provides a compact, cost-effective, and efficient motor control system with reduced electrical losses and minimal mechanical wear, enabling selective operation of multiple motors with reduced maintenance.
Implementation Method 1
a capacitor in parallel with the motor to be fed from a full wave rectified version of the same supply voltage, the circuitry comprising a bridge rectifier
Implementation Method 2
a bridge rectifier arranged to receive the supply voltage and to supply a full wave rectified version of the supply voltage to the capacitor and motor in parallel
Implementation Method 3
a fuse in series with the motor and capacitor
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a circuit (1) for selectively supplying exactly one motor of a plurality of motors (12, 16) with energy, which is provided by exactly one converter (10). The circuit (1) has a plurality of multi-phase motor terminals (9, 11) for connecting motors (12, 16), with exactly one multi-phase inverter terminal (3) for connecting exactly one inverter (10) and a plurality of electrical connections (5, 7), wherein each of the electrical connections (5, 7) comprises several phase lines (51, 71), wherein each of the electrical connections (5, 7) is connected to the inverter terminal (3), and wherein exactly one of the electrical connections (5, 7) is connected to exactly one of the motor terminals (9, 11), wherein in each phase line (51, 71) of an electrical connection (5, 7) exactly one MOSFET (21, 22) is arranged for selectively switching the respective phase line (51, 71).