Resolver Phase Shift Detection via Timer Signal Sampling
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Solution Overview
Problem
Rotational angle determining devices face challenges in detecting phase shifts between excitation and timer signals without increasing hardware costs, as built-in self-test functions and monitoring timers are resource-intensive.
Innovation Solution
A rotational angle determining device that includes a resolver, a resolver signal converting unit for sampling and A/D conversion of resolver signals at peak or trough values, and a phase shift detecting unit to identify phase shifts by periodically sampling and converting excitation signals, allowing for cost-effective phase shift detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a built-in self-test function or monitoring timer is provided to monitor synchronization between the excitation signal and timer signal, then phase shift detection capability is improved, but hardware cost and resource consumption increase
Solution Approach 1:
The excitation signal converting unit utilizes existing hardware resources (A/D converter, timer signal) to perform self-monitoring of phase shifts. Instead of adding dedicated monitoring hardware, the system uses the existing signal processing chain to detect phase shifts by converting the excitation signal itself and comparing its timing characteristics, thereby achieving self-service monitoring without additional hardware overhead.
Solution Approach 2:
The excitation signal converting unit serves multiple functions: it converts the excitation signal for rotational angle calculation and simultaneously monitors phase shifts between the excitation signal and timer signal. This multi-functionality allows the same hardware to perform both primary measurement and diagnostic monitoring, eliminating the need for separate dedicated monitoring hardware.
2Ease of manufacture
If hardware resources are reduced for cost reduction, then manufacturing cost is improved, but phase shift monitoring capability deteriorates
Solution Approach 1:
The system uses existing hardware resources (A/D converter, timer signal, excitation signal generating unit) to perform phase shift monitoring without requiring additional dedicated monitoring hardware. The excitation signal converting unit leverages the already-present signal processing chain to detect phase shifts, enabling cost-effective monitoring that does not compromise reliability.
Solution Approach 2:
The excitation signal converting unit creates a digital copy of the excitation signal through A/D conversion, which is then used for phase shift detection. This copied signal allows the system to monitor phase relationships without requiring separate physical monitoring circuits, reducing hardware costs while maintaining monitoring capability.
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
Enables accurate detection of phase shifts between excitation and timer signals while reducing hardware costs, ensuring reliable rotational angle determination even without extensive resource allocation.
Implementation Method 1
a resolver that is configured to receive an alternating current excitation signal, and to output an alternating current resolver signal induced by the excitation signal and having an amplitude that changes corresponding to a rotational angle of a rotor
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
A rotational angle determining device periodically samples a resolver signal output from a resolver receiving an alternating current excitation signal, the sampling being performed at a timing at which the excitation signal reaches a peak or trough value, based on a timer signal to which initial phase alignment is performed with respect to the excitation signal, and then the device performs A/D conversion of a voltage value of the sampled resolver signal, to determine the rotational angle of the rotor of the resolver. The excitation signal is periodically sampled at a predetermined timing based on the timer signal, and a presence or absence of a phase shift between the excitation and timer signals is detected based on a change in A/D converted value AD1n (n=1, 2, ...) obtained by A/D conversion of a voltage value of the sampled excitation signal.