Ripple Count Circuit for DC Motor Parasitic Pulse Cancellation
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Solution Overview
Problem
Conventional position measurement systems for electrically operated automotive components using DC motors are inefficient due to the need for expensive controllers and structural modifications to eliminate parasitic pulses, which result in signal noise and inaccurate readings.
Innovation Solution
A motor control system incorporating a ripple count circuit with an active filter and parasitic pulse cancellation circuit, utilizing an OR gate and low-pass RC filter to exclude parasitic pulses from the ripple signal without requiring additional CPU processing, thereby improving signal accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional position measurement systems use expensive controllers (FPGAs) to eliminate parasitic pulses, then measurement accuracy is improved, but system cost increases
Solution Approach 1:
The patent extracts and eliminates only the harmful parasitic pulses from the signal while preserving the useful ripple information. The cancellation circuit specifically targets and removes parasitic pulses generated during motor commutation, allowing accurate position measurement without requiring expensive FPGAs for comprehensive signal processing
Solution Approach 2:
The patent introduces an intermediary cancellation circuit that processes the raw ripple signal before it reaches the position measurement system. This intermediate processing stage removes parasitic pulses through analog circuitry (capacitors, resistors, operational amplifiers), serving as a mediator between the motor and the measurement system, thereby avoiding the need for complex digital processing in expensive controllers
2Measurement precision
If the motor assembly is structurally modified to generate normalized ripple patterns, then parasitic pulses are eliminated, but manufacturing cost and complexity increase
Solution Approach 1:
The patent replaces mechanical/structural modifications of the motor assembly with an electronic signal processing solution. Instead of physically altering the motor's magnetic ring, rotor, or stator to change ripple patterns, the invention uses an electronic cancellation circuit to remove parasitic pulses from the existing ripple signal, maintaining ease of motor manufacturing while achieving signal normalization
Solution Approach 2:
The patent changes the electrical parameters of the signal processing path rather than mechanical parameters of the motor. By adjusting circuit components (capacitor values, resistor ratios, operational amplifier gains) in the cancellation circuit, the system adapts to different motor characteristics without requiring physical motor modifications, thereby maintaining manufacturing simplicity
3Measurement precision
If ripple signals are processed using software or CPU, then parasitic pulses can be removed, but processing time and power consumption increase
Solution Approach 1:
The patent replaces software/CPU-based signal processing with hardware-based analog circuit processing. The cancellation circuit uses operational amplifiers, capacitors, and resistors to perform real-time parasitic pulse removal in the analog domain, eliminating the need for digital sampling, processing, and calculation that would consume CPU time and power
Solution Approach 2:
The patent implements continuous real-time parasitic pulse cancellation through the analog cancellation circuit, which operates continuously as the ripple signal passes through it. This continuous hardware processing eliminates the discrete time steps and processing delays inherent in software-based solutions, maintaining uninterrupted and immediate signal accuracy
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 effectively filters out parasitic pulses, enhancing the accuracy of rotor speed and position measurements in DC motor systems without increasing CPU processing time or power consumption, and reducing the need for costly hardware modifications.
Implementation Method 1
The active filter circuit is configured to filter the drive current and to generate a pulsed signal containing at least one parasitic pulse
Implementation Method 2
utilizing an OR gate and low-pass RC filter to exclude parasitic pulses from the ripple signal
Data Source
AI summary
A motor control system includes a direct current (DC) motor and a ripple count circuit. The DC motor includes a rotor induced to rotate in response to a drive current generated by a supply voltage. The rotation of the rotor generates a mechanical force that drives a component. The ripple count circuit includes an active filter circuit and a parasitic pulse cancellation circuit. The active filter circuit is configured to filter the drive current and to generate a pulsed signal containing at least one parasitic pulse. The parasitic pulse cancelation circuit is in signal communication with the ripple count circuit to receive the pulsed signal and to output a ripple count signal based on the pulsed signal. The ripple count signal excludes the at least one parasitic pulse.