BLDC Motor Rotor Position Alignment for Rapid Startup
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Solution Overview
Problem
Conventional BLDC motor driving control methods require initial position alignment of the rotor, which delays the start-up time and increases the time needed for feedback control.
Innovation Solution
The proposed driving control method skips the initial position alignment step by compulsively aligning and driving the rotor using forced alignment, allowing for immediate feedback control and rapid startup by aligning the rotor at a predetermined position using residual current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If forced alignment is performed repeatedly to align rotor position, then position accuracy is improved, but start-up time increases
Solution Approach 1:
The patent performs forced alignment only during initial startup to establish accurate rotor position, then uses this pre-established position information for subsequent feedback control without repeating alignment. This preliminary action eliminates the need for repeated alignment operations while maintaining position accuracy.
Solution Approach 2:
The patent extracts the forced alignment step from the regular operation cycle and isolates it to only the initial startup phase. By separating the alignment function from continuous operation, the system achieves position accuracy when needed without incurring time penalties during normal feedback control cycles.
2Measurement precision
If forced alignment is performed before each feedback control, then control precision is improved, but feedback control time increases
Solution Approach 1:
The patent performs forced alignment once at startup as a preliminary action to establish accurate rotor position information. This pre-established position data is then reused for feedback control, eliminating the need to perform alignment before each control cycle while maintaining control precision.
Solution Approach 2:
The patent maintains continuous feedback control operation using the rotor position information established during initial alignment. By keeping the control system continuously operational without intermittent alignment interruptions, the system achieves both precision and rapid response time.
3Measurement precision
If rotor position is repeatedly realigned, then position matching accuracy is improved, but productivity decreases
Solution Approach 1:
The patent performs forced alignment as a preliminary action only during initial startup to establish accurate rotor position. This one-time alignment enables subsequent rapid feedback control operations without repeated alignment interruptions, thereby maintaining both position matching accuracy and high productivity.
Solution Approach 2:
The patent skips the forced alignment step during subsequent feedback control operations after initial startup. By rushing through the control process without repeating the alignment step, the system maintains position accuracy while significantly improving response speed and overall productivity.
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 method enables the BLDC motor to perform feedback control within the shortest time without delays, reducing the pressure rise time and allowing for rapid achievement of desired pressure in applications like fuel pumps.
Implementation Method 1
the inverter (70) converts DC voltage applied by bridge diode (not described in the FIG. 1) into AC voltage
Implementation Method 2
initial driving algorism is disclosed in which the BLDC motor detects position of rotation in stop state by pulse train acquired from change of inductance
Implementation Method 3
PWM processor (50) modulate (i.e. pulse width modulation) the driving signal input from driving signal generator (S30) along with information on the rotation velocity input from velocity controller (40)
Implementation Method 4
each transistor performs on/off switching operation to provide AC voltage to each phase (A, B, C) of each stator
Implementation Method 5
When the AC voltage is applied to the BLDC motor (10), the rotor of the BLDC motor (10) is rotated
Data Source
AI summary
Provided is driving control method of Brushless DC (BLDC) motor, including: a step of initial driving command input, initially inputting a driving command to the BLDC motor; a step of the first position alignment, compulsively aligning rotor of the BLDC motor at a predetermined position; a step of forced driving, compulsively driving the rotor of the BLDC motor compulsively aligned by accelerating the rotor of the BLDC motor; a step of feedback control, performing feedback control of the BLDC motor; a step of driving off, inputting a stop command to the BLDC motor; and a step of the second position alignment, compulsively aligning the rotor of the BLDC motor at the predetermined position again.