Three-Point Inverter Circuit for High-Speed Motor Deceleration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electric vehicles face limited deceleration torque at high speeds when operating in generator mode due to the electric voltage being constrained by the DC voltage source, leading to inefficient energy conversion and the need for additional mechanical deceleration systems.
Innovation Solution
A control circuit incorporating a three-point inverter and an electrical resistor (chopper resistor) is used to convert excess electrical energy into thermal energy, allowing higher deceleration torque by supplying voltage beyond the DC voltage source limits, especially at high speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a conventional two-level inverter is used to decelerate the electric machine in generator mode, then the electric machine can convert kinetic energy to electrical energy, but the deceleration torque significantly decreases at high speeds due to voltage constraints from the DC voltage source
Solution Approach 1:
The patent segments the voltage output into three levels (positive DC voltage, negative DC voltage, and zero voltage) using a three-point inverter with neutral point clamping. This segmentation allows the inverter to provide higher voltage across the motor terminals during deceleration, enabling significantly higher deceleration torque at high speeds compared to conventional two-level inverters that are constrained by the DC source voltage.
Solution Approach 2:
The patent introduces a chopper resistor as an intermediary component connected between the neutral point and the positive DC terminal. This resistor acts as a mediator to dissipate excess regenerative energy when the motor generates voltage higher than the DC source voltage, allowing the three-point inverter to maintain higher deceleration torque by providing an additional voltage level without requiring an oversized DC voltage source.
2Force
If the DC voltage source voltage is increased to provide higher deceleration torque at high speeds, then the deceleration performance improves, but the cost and complexity of the power source increases
Solution Approach 1:
The patent employs dynamic switching control of the three-point inverter to dynamically adjust the voltage levels applied to the motor during deceleration. By dynamically switching between the three voltage levels (positive, negative, zero) and utilizing the chopper resistor for energy dissipation, the system achieves high deceleration torque without requiring a statically higher DC voltage source, thus avoiding increased power source complexity.
Solution Approach 2:
The patent changes the operational parameters of the inverter by implementing three-level voltage output instead of conventional two-level output. This parameter change in the inverter topology allows the system to achieve higher effective voltage across the motor terminals during deceleration while maintaining the same DC source voltage, thereby improving deceleration torque without increasing power source complexity or cost.
3Force
If a three-point inverter with chopper resistor is used to achieve high deceleration torque, then the deceleration performance across the entire operating range improves, but the device complexity increases due to additional components
Solution Approach 1:
The three-point inverter structure serves multiple functions: it provides three-level voltage output for high deceleration torque, enables regenerative energy recovery by feeding energy back to the DC source, and dissipates excess energy through the chopper resistor when needed. This multi-functionality allows the same inverter structure to handle various operating conditions without requiring separate systems, thereby managing complexity while achieving superior deceleration performance.
Solution Approach 2:
The chopper resistor is nested within the inverter structure, specifically connected between the neutral point and the positive DC terminal. This nested configuration allows the energy dissipation function to be integrated into the existing inverter topology rather than requiring a separate external circuit, thereby minimizing additional complexity while enabling the three-level voltage operation and high deceleration torque capability.
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
The solution enables high deceleration torque across the entire operating range of the electric machine, potentially eliminating the need for mechanical deceleration systems and optimizing energy management by converting excess energy into thermal energy.
Implementation Method 1
The method comprises a step of rectifying an AC voltage supplied by the electric machine at the AC voltage terminal and a step of supplying the rectified AC voltage at the DC voltage terminal of the control circuit
Implementation Method 2
at least some of the electrical energy of the rectified AC voltage is supplied at an electrical resistor between the central terminal and the first connection point
Data Source
AI summary
The invention relates to a circuit assembly for better decelerating a rotating electric machine by means of a three-point inverter. For this purpose, an electrical resistor is supplied between a central terminal and an outer terminal of the three-point inverter. This electrical resistor allows some of the electrical energy generated during the deceleration of the electric machine to be converted into thermal energy as needed.