Vehicle Battery Charging Apparatus Sensor Phase Error Correction
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Solution Overview
Problem
In battery charging apparatuses for vehicles, accurate energization control of the stator coil in a three-phase brushless motor or AC generator is hindered by errors in the attaching position of the rotor sensor, leading to inaccurate motor output control, especially at low engine revolution speeds where fluctuation is significant and precise measurement is challenging.
Innovation Solution
A battery charging apparatus with a control circuit that detects phase differences between the position detection signal and output signals of the three-phase AC generator, using a correction map to estimate and correct phase differences, allowing for precise energization control based on the phase of the induced voltage, even at higher revolution speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the position sensor is attached to detect rotor rotation in a three-phase AC generator, then energization control of the stator coil can be executed, but phase shift between sensor signal and induced voltage causes inaccurate energization timing
Solution Approach 1:
The patent replaces direct mechanical sensor attachment with a signal-based detection method. By detecting the zero-cross point of induced voltage and comparing it with the sensor signal rise, the system substitutes physical sensor positioning with electrical signal analysis to achieve accurate phase alignment without mechanical attachment errors
Solution Approach 2:
The patent implements feedback by detecting the phase shift between the sensor signal and induced voltage, then using this detected phase shift to correct the energization timing. The control system continuously monitors the phase relationship and adjusts energization timing based on the detected phase error, creating a closed-loop control system
2Ease of manufacture
If the rotor sensor attaching position has an error, then sensor signal output timing shifts, but appropriate energization timing of stator coil cannot be secured
Solution Approach 1:
The patent converts the harmful effect of sensor position errors into a useful measurement. By intentionally detecting the phase shift caused by attachment position errors, the system transforms manufacturing imprecision into quantifiable data that can be used to correct energization timing, turning a defect into a diagnostic opportunity
Solution Approach 2:
The patent changes the approach from fixing the sensor position physically to adjusting the energization timing parameter based on detected phase shift. Instead of attempting to manufacture perfect sensor alignment, the system measures the actual phase relationship and adjusts the control parameter (energization timing) to compensate for manufacturing variations
3Measurement precision
If phase shift detection is performed in regenerative power generation state, then accurate energization control can be achieved, but the method cannot be applied in battery charging apparatus with regulator
Solution Approach 1:
The patent creates a universal phase detection method that works across different system configurations. By detecting the zero-cross point of induced voltage and comparing it with sensor signal rise, the system achieves phase shift detection that is applicable to both regenerative power generation systems and battery charging apparatus with regulators, eliminating the limitation of application-specific methods
Solution Approach 2:
The patent introduces the zero-cross point of induced voltage as an intermediary reference point for phase detection. This intermediary allows the system to establish a common reference frame that works regardless of whether the system is in regenerative mode or battery charging mode with a regulator, enabling universal application of the detection method
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
This solution enables precise energization control by estimating and correcting phase differences, thereby accurately detecting and addressing errors in the sensor position, ensuring stable and efficient battery charging across various revolution speed ranges.
Implementation Method 1
a position sensor configured to output a position detection signal that expresses a rotation position of a rotor of a three-phase AC generator
Implementation Method 2
a regulator that includes a plurality of rectifying elements and a plurality of switching elements. The regulator is configured to supply DC power obtained by rectifying three-phase AC outputted from the three-phase AC generator
Data Source
Figure 1
Figure 2(a)~2(c)
Figure 3
AI summary
To detect an error of an attaching position of a sensor that detects rotation of a rotor of a generator. A battery charging apparatus includes a position sensor 42 that outputs a position detection signal that expresses a rotation position of a rotor 12 of a generator 10, a sensor that detects an output current or an output voltage of a predetermined phase, a regulator 20 that includes a plurality of rectifying elements and a plurality of switching elements and supplies DC power obtained by rectifying three-phase AC outputted from the generator 10 to a battery 24, and an inverter control section 30 that executes energization control of the respective switching elements of the regulator 20 based on a phase of an induced voltage of the generator 10 calculated on the basis of the position detection signal. The inverter control section 30 inputs a revolution speed signal Ne that shows a revolution speed of the generator 10, the position detection signal Tp, and either output signal out of a current signal or a voltage signal detected by the sensor, and estimates an error of an attaching position of the position sensor 42 with respect to the induced voltage of the predetermined phase based on the position detection signal and the output signal.