Motor Control Device Dynamic Braking and Rotor Locking
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Solution Overview
Problem
Motor driving control devices using single-sensor driving methods face challenges in quickly activating motors due to the need for prolonged short-circuit braking and lock times, which can be inefficient, especially when the motor state changes rapidly.
Innovation Solution
A motor driving control device and method that employs a control circuit unit to execute short-circuit braking and lock operations based on predetermined time conditions and position signal variations, allowing for quick activation by monitoring position signals and adjusting energization phases and current values to efficiently position and lock the rotor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the short-circuit braking time or lock time is set according to the state that takes the longest time to stop the rotor, then the motor can be reliably stopped in all states, but it takes a long time until activation control is started even in states where it takes little time to stop the rotor
Solution Approach 1:
The patent applies dynamics by making the short-circuit braking time and lock time variable rather than fixed. The control unit dynamically adjusts these time parameters based on the actual rotor state detected during operation. Specifically, the system monitors rotor position and speed, and adaptively modifies the braking and locking durations to match the current operational conditions, thereby achieving both reliability and speed optimization
Solution Approach 2:
The patent implements parameter changes by modifying the time parameters (short-circuit braking time and lock time) based on detected rotor states. The control unit changes these parameters in response to variations in rotor position, speed, and load conditions. This allows the system to use shorter times when the rotor is already near stopping point and longer times when greater braking is required, resolving the contradiction between fixed-time reliability and variable-time efficiency
2Device complexity
If a single hall sensor is used for detecting magnetic pole position, then the device complexity is reduced, but it becomes impossible to specify the magnetic pole position accurately without rotor-lock
Solution Approach 1:
The patent applies preliminary action by performing rotor-lock before activation control. This preliminary positioning operation uses the single hall sensor to bring the rotor to a known reference position where the magnetic pole position can be accurately determined. By establishing this initial known state, the system compensates for the limitation of using only one sensor, enabling subsequent accurate control without requiring multiple sensors
Solution Approach 2:
The patent uses the rotor-lock operation as an intermediary step that bridges the gap between single-sensor detection and accurate magnetic pole positioning. The rotor-lock process acts as a mediator that transforms the incomplete information from a single hall sensor into a complete and accurate position specification by mechanically positioning the rotor at a predetermined angle where the magnetic pole aligns with the sensor
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 rapid motor activation by optimizing short-circuit braking and lock operations, reducing overall activation time and preventing overheating, even in states with external forces or varying rotational speeds.
Implementation Method 1
a position detector corresponding to one phase out of the plurality of phases, the position detector outputting a position signal having a phase varying according to a position of a rotor of the motor
Implementation Method 2
a motor driving unit for selectively energizing coils of a plurality of phases of a motor
Data Source
AI summary
A motor driving control device includes: a motor driving unit for selectively energizing coils of a plurality of phases of a motor; a control circuit unit for outputting a driving control signal to the motor driving unit to control an operation of the motor driving unit; and a position detector corresponding to one phase out of the plurality of phases, the position detector outputting a position signal having a phase varying according to a position of a rotor of the motor, wherein when starting activation of the motor, the control circuit unit executes first control for causing the motor to perform short-circuit braking, and second control for starting a first lock operation in which the rotor is locked by energizing coils of a predetermined energization phase out of the plurality of phases with a first current value after the first control is executed, and when executing the first control, the control unit performs the short-circuit braking from the start of the short-circuit braking of the motor until variation of a predetermined pattern of the phase of the position signal has not been detected over a first predetermined time, or from the start of the short-circuit braking of the motor until a second predetermined time longer than the first predetermined time has elapsed.