Electric Pump Motor State Discrimination via Pulse Signal Modulation
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Solution Overview
Problem
Existing electric pumps face limitations in accurately discriminating the state of a motor due to the restricted number of discriminable states based on pulse signal frequencies and voltages, leading to difficulties in diagnosing malfunctions and operational conditions.
Innovation Solution
The electric pump incorporates a control unit that modifies both the frequency and duty ratio of the pulse signal to differentiate between drive and stop states, as well as various stop states, allowing for more precise discrimination by outputting a combination of frequency and duty ratio information via a single communication line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the electric pump uses pulse signal frequency and voltage levels to discriminate motor states, then the system can distinguish between drive and stop states, but the number of discriminable states is limited to four maximum
Solution Approach 1:
The patent transitions from using only frequency dimension to using both frequency and duty ratio dimensions of the pulse signal. This dimensional expansion allows the system to distinguish between multiple stop states (normal stop, lock malfunction, freezing) in addition to drive states, thereby increasing the number of discriminable states beyond the previous four-state limitation while maintaining accurate state discrimination.
2Loss of information
If the electric pump uses multiple signal lines for communication, then more information can be transmitted, but the device complexity increases
Solution Approach 1:
The patent combines multiple information channels (frequency information and duty ratio information) into a single pulse signal transmitted over one signal line. The control unit modulates both the frequency and duty ratio of the same pulse signal to encode different motor states, thereby eliminating the need for separate signal lines while maintaining full information transmission capability for state discrimination.
3Ease of manufacture
If the electric pump uses only frequency variation for state indication, then the system is simple to implement, but the ability to distinguish between different stop states is insufficient
Solution Approach 1:
The patent changes the pulse signal parameters from only frequency variation to both frequency and duty ratio variation. Different motor states are represented by unique combinations of frequency and duty ratio values, enabling the system to distinguish between normal stop, lock malfunction, and freezing states with high accuracy while maintaining implementation simplicity through a single signal line and unified control approach.
Data Source
AI summary
An electric pump includes: a motor that drives a pump; and a control unit to which an input signal for driving the motor is input from an external device, which outputs a drive signal based on the input signal, and which outputs a pulse signal indicating a rotation state of the motor to the external device, in which the control unit is configured to change both of a frequency and a duty ratio of the pulse signal so as to be capable of discriminating whether the motor is in a drive state or a stop state and between a plurality of states of the motor in the stop state.