Manned Mower Battery Layout for Stable Sensorless Motor Detection
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Solution Overview
Problem
Existing electric mowers face challenges in accurately detecting the rotor position of the electric motor during heavy-load operations, leading to motor shutdown and poor user experience due to contradictions between ripple and hysteresis in rotational speed estimation.
Innovation Solution
A manned mower design that includes a traveling wheel set, a vehicle frame, a support portion for the operator, and a power supply assembly with detachable battery packs. The power supply assembly is strategically positioned between left and right bracket portions on the vehicle frame, ensuring efficient power distribution and management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the detection method without position sensor is used to reduce device complexity, then the rotor position detection accuracy deteriorates during heavy-load operation
Solution Approach 1:
The patent introduces an intermediary mechanism (rotational speed estimation through back electromotive force measurement) to indirectly obtain rotor position information without direct sensor contact. This mediator allows the system to infer position data from electrical characteristics, resolving the contradiction between sensor-less operation and position accuracy.
Solution Approach 2:
The patent replaces the mechanical/physical position sensor with an electrical field-based detection method. By measuring back electromotive force and deriving rotational speed, the system substitutes direct mechanical position sensing with indirect electrical measurement, reducing device complexity while maintaining functional capability.
2Measurement precision
If the rotational speed estimation is improved to enhance measurement precision, then the contradiction between ripple and hysteresis worsens
Solution Approach 1:
The patent employs parameter changes in the detection methodology, adjusting measurement frequencies and signal processing parameters to optimize the balance between ripple reduction and hysteresis minimization. By dynamically modifying detection parameters based on operational conditions, the system maintains reliable rotor position acquisition while improving speed estimation precision.
3Volume of moving object
If the power supply assembly is compacted to reduce volume, then the energy capacity is insufficient
Solution Approach 1:
The patent applies nesting by integrating the power supply assembly within the vehicle frame structure, utilizing available spatial voids and contours. The battery pack is nested between the left and right bracket portions, maximizing space utilization without requiring additional external volume, thereby achieving high energy capacity within compact dimensions.
Solution Approach 2:
The patent optimizes the power supply arrangement by transitioning from a single-dimensional linear layout to a multi-dimensional spatial configuration. The battery pack is positioned vertically between the bracket portions, utilizing the up-down dimension rather than only left-right extension, achieving compact volume with sufficient energy capacity.
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 reliable and efficient power supply to the traveling electric motor, enhancing the accuracy of rotor position detection and preventing motor shutdown during heavy-load operations, thus improving user experience.
Implementation Method 1
a power supply assembly used for supplying power to at least the traveling electric motor and including at least one detachable battery pack
Data Source
AI summary
A manned mower includes a traveling wheel set; a vehicle frame; a support portion used for supporting an operator; a traveling electric motor used for driving the traveling wheel set; and a power supply assembly used for supplying power to at least the traveling electric motor and including at least one detachable battery pack. The vehicle frame includes a left bracket portion and a right bracket portion for supporting the power supply assembly, the power supply assembly is disposed between the left bracket portion and the right bracket portion, and a maximum inner width W1 of the left bracket portion and the right bracket portion in a left and right direction is less than or equal to 700 mm, and total energy of a single row of the power supply assembly along the left and right direction is greater than or equal to 8 kW·h.