Electric Brake Device Angle-Sensorless Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electric brake devices face challenges in accurately estimating motor angle during low-speed operations and high-speed fluctuations, leading to estimation errors and increased power consumption due to the need for high-frequency voltage superposition and large motor currents, which complicates angle-sensorless control and increases motor size, weight, and cost.
Innovation Solution
An electric brake device with an angle-sensorless control system that determines the phase of the motor current based on the deviation between the braking force command and estimated values, allowing for accurate follow-up control without an actual angle sensor, reducing component count and power consumption by adjusting motor current according to calculated electrical angular speed and angle, and incorporating a responsiveness-restricting function for stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an angle sensor is used to control the electric motor, then the motor can be driven efficiently, but the device complexity increases and redundancy decreases
Solution Approach 1:
The patent extracts and eliminates the angle sensor from the motor control system by implementing sensorless vector control. The control device estimates the motor angle and magnetic flux using mathematical models and measured electrical quantities (currents and voltages) instead of relying on physical sensors, thereby simplifying the device structure and improving redundancy.
Solution Approach 2:
The patent replaces the mechanical/electrical sensing system with a computational estimation system. Instead of using physical sensors to detect motor angle and flux, the control device uses software-based observers and mathematical models to calculate these parameters from electrical measurements, substituting hardware sensing with computational methods.
2Reliability
If angle-sensorless control is implemented using high-frequency voltage superposition, then motor angle can be estimated without sensors, but power consumption increases and motor size increases
Solution Approach 1:
The patent changes the control parameters and estimation methods to achieve accurate angle estimation without high-frequency voltage superposition. By using improved observer algorithms and mathematical models that operate at fundamental frequency, the system maintains reliable angle estimation while avoiding the excessive power consumption and motor sizing requirements associated with high-frequency injection methods.
3Stability of the object's composition
If large motor currents are used to maintain stability during high-speed fluctuations, then control stability is maintained, but power consumption increases
Solution Approach 1:
The patent implements dynamic current control that adapts to operating conditions. The control device adjusts motor currents based on real-time estimates of motor angle, speed, and load conditions, providing sufficient current only when needed for stability while reducing current magnitude during steady-state operation, thereby maintaining control stability without excessive power consumption.
Solution Approach 2:
The patent uses feedback control with estimated motor parameters to regulate current magnitude. The control device continuously monitors motor operation, estimates angle and flux, and adjusts current commands accordingly, providing just enough current to maintain stability during high-speed fluctuations while minimizing power consumption during normal operation.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The electric brake device includes a control device (2) for performing follow-up control such that a braking force estimated value estimated by a braking force estimator (26) follows a given braking force command value. The control device (2) includes an angle-sensorless control function section (20) for determining a phase of phase current of an electric motor (4) irrespective of an actual angle of the electric motor (4) and controlling the electric motor (4) to have a current value that is based on the determined phase of the phase current. The angle-sensorless control function section (20) includes a current phase determination section (25b) for determining a current phase that is the phase of the phase current of the electric motor (4) on the basis of a deviation between the braking force command value and the braking force estimated value.