Asynchronous Drive Device with Dual Independent Rotors
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Solution Overview
Problem
Existing drive devices for motor vehicles with two drivable wheels require multiple expensive components and complex control systems to achieve differential rotational speeds, increasing production and installation costs.
Innovation Solution
An asynchronous electric machine with two independently rotating rotors and a single stator, where the rotor resistance can be adjusted using semiconductor switches or potentiometers, allowing for simplified control and reduced component count by using a single power output stage and inverter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two separate electric machines with independent control units and power output stages are used for each wheel, then differential rotational speeds can be achieved, but production costs and installation costs increase significantly
Solution Approach 1:
The patent combines two separate electric machines into a single asynchronous machine with two rotors that can rotate independently. The stator serves both rotors simultaneously, merging what would traditionally be two separate drive units into one integrated component. This reduces the number of control units and power output stages from two to one, directly addressing the cost and complexity issues while maintaining differential speed capability through independent rotor control via resistance adjustment devices
Solution Approach 2:
The single stator is designed to serve dual purposes by simultaneously supporting two independently controllable rotors. This multi-functional design allows one stator and its associated control system to perform the work of two separate machines, achieving cost reduction without sacrificing the adaptability needed for differential wheel rotation
2Adaptability or versatility
If a differential gear is used to connect drive machine to both wheels, then differential rotational speeds are achieved, but mechanical complexity and installation space requirements increase
Solution Approach 1:
The patent replaces the mechanical differential gear system with an electrical control mechanism. Instead of using mechanical gears to achieve differential rotation, the invention uses independent adjustment of rotor resistance in an asynchronous machine to control the rotational speed of each wheel electronically. This substitution eliminates complex mechanical components while achieving the same functional outcome of differential wheel speeds
3Adaptability or versatility
If rotor resistance adjustment device is added to enable independent rotor control, then differential rotational speeds are achieved, but component count increases
Solution Approach 1:
The patent controls the rotational speed of each rotor by adjusting the electrical resistance parameter of the rotor windings. By changing the resistance value, the synchronous speed of the asynchronous machine changes, allowing independent speed control of each rotor. This parameter-based control method achieves differential rotation without adding complex mechanical or electronic control components
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 solution reduces production and installation costs while maintaining functionality, enabling efficient control of rotational speed and torque differences between wheels, thus enhancing driving stability without the need for a differential gear.
Implementation Method 1
the device comprises at least one semiconductor switch that is connected in series to a phase of a winding of the rotor, said winding comprising in particular multiple phases, and said semiconductor switch can be controlled so as to change the electrical resistance of the phase
Implementation Method 2
the electrical machine is embodied as an asynchronous machine and comprises two rotors that can rotate independently of one another
Data Source
AI summary
The invention relates to a drive device (8) for a motor vehicle (1) having two drivable wheels (6, 7) on a wheel axle (3), said drive device comprising an electric machine (9), which is designed as an asynchronous machine and which has at least one stator (10) and at least one rotor (11, 12), wherein the rotor (11, 12) is or can be operatively connected to at least one of the wheels (6, 7) in order to drive said wheel. According to the invention, the electric machine (9) has two rotors (11, 12), which can rotate independently of one another, each of which is or can be operatively connected to one wheel (6, 7) of the wheel axle (3), and a device for varying the electric rotor resistance of at least one of the rotors (11, 12).