Stepping Motor Driving Circuit with External Load Angle Output
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Solution Overview
Problem
Existing stepping motor driving circuits cannot provide external access to load angle information, making it difficult to determine the state of the motor or optimize control parameters during changes in load or speed.
Innovation Solution
A driving circuit for stepping motors that includes a counter electromotive force (EMF) detection circuit, revolution count detection circuit, and load angle estimating portion, capable of outputting load angle information externally, and featuring a current value setting circuit, constant current chopper circuit, and logic circuit to control coil currents and output angle information as digital or analog signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If load angle information is kept internal for feedback control, then control stability is improved, but external access to motor state information is lost
Solution Approach 1:
The patent extracts the load angle information from the internal feedback control loop and provides it through a separate output interface. The load angle calculating portion computes the load angle based on counter EMF and revolution count, then this calculated information is made accessible externally through a dedicated output circuit without interfering with the internal feedback mechanism that uses the same data for control stability.
Solution Approach 2:
The patent introduces an intermediary output interface that mediates between the internal load angle calculation and external access requirements. The output circuit acts as a mediator that transmits the calculated load angle information to external devices without disrupting the internal feedback control pathway, thus preserving control stability while enabling information accessibility.
2Reliability
If constant current value is used during acceleration and deceleration, then out-of-step prevention is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic current value adjustment based on the calculated load angle. The current value setting portion uses the load angle information to determine appropriate current levels, switching between constant high current during acceleration/deceleration for out-of-step prevention and optimized current levels during constant speed operation for energy efficiency.
Solution Approach 2:
The patent changes the current parameter dynamically based on operating conditions and load angle. By monitoring the load angle and adjusting the current value accordingly, the system maintains high torque during acceleration and deceleration when out-of-step risk is high, while reducing current during constant speed operation to minimize power consumption.
3Use of energy by moving object
If feedback control based on counter EMF is implemented, then power consumption is reduced, but complexity of the driving circuit increases
Solution Approach 1:
The patent makes the counter EMF detection circuit serve multiple functions: it detects counter EMF for feedback control to optimize power consumption, simultaneously provides signal for load angle calculation, and enables external access to motor state information. This multi-functionality reduces the need for separate circuits and minimizes overall system complexity.
Solution Approach 2:
The patent merges the load angle calculation function with the existing feedback control circuitry. The load angle calculating portion utilizes the same counter EMF detection and revolution count data already present in the feedback control system, combining multiple functions into a unified circuit architecture that achieves power efficiency without proportionally increasing complexity.
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 external access to load angle information, allowing for effective determination of motor state and optimization of control parameters, reducing the risk of out-of-step conditions and improving efficiency by adjusting current settings based on feedback control.
Implementation Method 1
a counter electromotive force (EMF) detection circuit, detecting a counter EMF generated in a coil
Data Source
AI summary
The task of the present invention is to provide a driving circuit capable of outputting information useful to design or control of a system to outside. The present invention relates to a driving circuit and a driving method of a stepping motor, and an electronic machine using the driving circuit of a stepping motor. A counter electromotive force detection circuit detects a counter EMF generated in a coil. A revolution count detection circuit acquires the revolution count of the stepping motor. A load angle estimating portion calculates a load angle according to the counter EMF and the revolution count. An interface circuit is configured to be capable of outputting angle information associated with the load angle to outside, or accessing the angle information from the outside.