Motor Drive Control Circuit for Overcurrent Detection
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Solution Overview
Problem
Existing motor drive control devices face challenges in distinguishing between overcurrent states caused by overload and failures, leading to inadequate abnormality countermeasures and increased manufacturing costs due to complex circuit configurations.
Innovation Solution
A motor drive control device with a control circuit unit that sequentially switches energization patterns for phase coils, using a first determination unit to detect overcurrent and a second unit to assess abnormal conditions, allowing for precise identification of motor abnormalities through a simple circuit configuration, including a current detecting circuit and PWM signal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a complex circuit configuration with separate detection circuits for power supply source side and ground line side is used to detect abnormal current flow, then the precision of detecting switch element failures is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines the power supply source side current detection circuit and the ground line side current detection circuit into a single integrated current detection circuit. This merging reduces the number of separate circuits needed while maintaining the capability to detect abnormal current flows through switch elements, thereby reducing device complexity and manufacturing cost without sacrificing detection precision
Solution Approach 2:
The integrated current detection circuit is designed to perform multiple functions: it can detect current on the power supply source side, detect current on the ground line side, and identify abnormal current flows through switch elements. This multi-functional design eliminates the need for separate dedicated detection circuits for each function, reducing overall circuit complexity while maintaining comprehensive monitoring capability
2Reliability
If the current limit operation stops the ON/OFF operation of switch elements upon overcurrent detection, then the motor is protected from overload damage, but the ability to distinguish between overload and failure conditions is lost
Solution Approach 1:
The control circuit performs preliminary analysis of the overcurrent condition by examining which specific switch elements are conducting current during the overcurrent event. By determining the conduction state of each switch element before executing the current limit operation, the system can identify whether the overcurrent is caused by motor overload or switch element failure, preserving diagnostic information while still providing motor protection
Solution Approach 2:
The control circuit uses feedback from the current detection circuit to determine the conduction state of switch elements during overcurrent conditions. This feedback mechanism allows the system to distinguish between overload and failure conditions by analyzing the current distribution pattern across switch elements, enabling appropriate countermeasure selection while maintaining motor protection
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 effective determination of motor abnormalities, preventing unnecessary shutdowns and reducing manufacturing costs by distinguishing between overload and failure-induced overcurrent states, ensuring proper countermeasures can be taken.
Implementation Method 1
a current detecting circuit for detecting a voltage value corresponding to a magnitude of the driving current
Data Source
AI summary
According to an aspect of the present disclosure, a motor drive control device includes a motor drive unit having a plurality of switch elements connected to a power supply source and supplying a driving current to a plurality of phase coils of a motor, a control circuit unit outputting, to the motor drive unit, a drive control signal for operating the plurality of switch elements to sequentially switch energization patterns for the plurality of phase coils, and a current detecting circuit for detecting a voltage value corresponding to a magnitude of the driving current, wherein the control circuit unit includes a first determination unit determining whether a state of overcurrent where a magnitude of the driving current exceeds a predetermined overcurrent threshold occurs based on the voltage value each time an energization pattern is switched, and a second determination unit determining whether driving of the motor is in an abnormal condition based on a determination result of the first determination unit for a plurality of energization patterns.