Synchronous Machine Control for Stable Standstill
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing control systems for electrical synchronous machines in vehicles struggle to maintain a stable standstill without oscillating movements, particularly when braking, due to challenges in adapting braking force to varying surface conditions and vehicle load, which can lead to uneven torque distribution and potential gearbox damage.
Innovation Solution
A method for controlling an electrical synchronous machine that involves operating the machine with deceleration torque, monitoring rotor speed, and adjusting electrical input variables to establish a stable torque balance between external and internal torques, allowing the vehicle to remain stationary by maintaining a constant phase position of the electrical input variable, even after direction reversal or zero speed is reached.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional speed control is used with constant torque according to brake pedal input, then braking force is applied uniformly to all wheels, but wheels on loose ground can slip while wheels on firm ground are still rolling, leading to unstable standstill and oscillating movements
Solution Approach 1:
The patent applies dynamics by continuously adapting the torque distribution to changing surface conditions and vehicle state. The control system dynamically adjusts the torque applied to each wheel based on real-time feedback from sensors detecting wheel speed, surface conditions, and vehicle motion, enabling stable standstill despite varying external conditions.
Solution Approach 2:
The patent implements feedback control by using sensors to monitor wheel speed, surface conditions, and vehicle motion, then using this information to continuously adjust the braking torque distribution. The control system compares actual vehicle state with desired state and modifies torque application to eliminate deviations, preventing oscillating movements and achieving stable standstill.
2Speed
If heavy load changes occur in the gearbox during braking, then deceleration torque is applied to slow the vehicle, but there is a risk that the tooth flanks will be damaged
Solution Approach 1:
The patent applies preliminary action by preparing the gearbox for heavy load changes before they occur. The control system anticipates the torque requirements during deceleration and pre-adjusts the torque distribution to minimize sudden load transitions, thereby protecting the gearbox tooth flanks from damage while still achieving the required deceleration.
3Stability of the object's composition
If torque is introduced symmetrically to the longitudinal axis to prevent gear moments, then vehicle stability is supported, but it is difficult to adapt the braking force to varying surface conditions and vehicle load
Solution Approach 1:
The patent applies local quality by treating each wheel independently with customized torque application based on its specific surface conditions and vehicle position. Instead of uniform symmetric torque distribution, the control system adjusts the braking force at each wheel location according to local conditions such as surface friction, wheel load, and position in the vehicle, thereby maintaining overall vehicle stability while adapting to varying conditions.
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 approach enables the synchronous machine to maintain a stable standstill without oscillating movements, effectively balancing driving and braking moments, ensuring the vehicle remains stationary despite external forces, without the need for position or speed controllers, and reduces the risk of gearbox damage.
Implementation Method 1
the drive torque is provided via the magnetic field of one or more three-phase synchronous motors
Implementation Method 2
When braking, a moment is developed which counteracts the current direction of movement of the vehicle and machine, with the kinetic energy of the vehicle and machine being converted into electrical energy
Data Source
Figure 1
Figure 2a~2c
Figure 3a~3c
AI summary
A method for controlling a synchronous electric machine (2) comprising a stator and a rotor encompasses the following steps: the machine (2) is operated at a deceleration moment (MP) such that a rotor speed of the machine is reduced; the rotor movement of the machine is monitored, and when a rotation in the opposite direction or a rotor speed (v) of nearly zero with a transition into a blocked mode is detected, at least one electric input variable (I; iu, iv, iw) of an electric stator system of the machine is adjusted in such a way that an effective internal moment (MB) of the machine is generated at the beginning of the blocked mode, said internal moment (MB) being smaller than the deceleration moment (MP). The electric input variable (I; iu, iv, iw) is adjusted in this way until a stable equilibrium between an external moment (MA) affecting the machine and the internal moment (MB) has been reached by moving the rotor and under the influence of said external moment (MA).