HIL Simulation of Multiphase Drives Using Virtual String Switches
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Solution Overview
Problem
Existing methods for simulating multiphase electric drives in hardware-in-the-loop simulations face challenges due to inaccurately computed reactive potentials, which can lead to incorrect string currents, especially in magnetically asymmetrical drives.
Innovation Solution
The method involves supplementing the mathematical model of the electric drive with virtual switches, which are opened or closed based on evaluated string voltages and currents to reduce the influence of incorrect string voltage measurements on current computations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the mathematical model computes string currents based on measured string voltages in a multiphase electric drive, then the simulation provides real-time feedback for control device testing, but inaccurately computed reactive potentials lead to incorrect string currents
Solution Approach 1:
The patent introduces a potential-free string terminal as an intermediary element that decouples the inaccurate reactive potential computation from the current calculation. By connecting one string terminal to a potential-free supply terminal, the system eliminates the need to compute reactive potentials for that terminal, thereby removing the source of computation errors while maintaining real-time simulation capability
Solution Approach 2:
The patent changes the electrical state parameter of one string terminal from potential-carrying to potential-free. This parameter change transforms the terminal from requiring reactive potential computation to being electrically isolated, thereby eliminating the accuracy problem while preserving the functional integrity of the simulation
2Reliability
If the simulator uses a mathematical model to compute string currents from measured string voltages, then the simulation reflects actual drive behavior, but magnetically asymmetrical drives produce inaccurately computed reactive potentials
Solution Approach 1:
The patent extracts the problematic reactive potential computation from the system by removing the voltage connection at one string terminal. By taking out the terminal from the potential network and connecting it to a potential-free supply terminal, the system eliminates the source of computation errors related to magnetically asymmetrical drives while maintaining the simulation's ability to reflect actual drive behavior through the remaining connected terminals
Data Source
AI summary
A computer-implemented method for simulating a multiphase electric drive having energizable strings, using a hardware-in-the-loop simulator for testing a power electronic control device with an integrated inverter is provided. The simulator, based on a mathematical model of the electric drive, computes the string currents in the strings of the drive, and an electrical reactive potential of the potential-free string terminal resulting from the drive reaction. The potential-free string terminal is set to the reactive potential by a voltage emulator. The method reduces the influence of inaccurately computed reactive potentials on the simulation by supplementing the mathematical model of the electric drive in the strings in each case by a virtual switch. The virtual switches in the open state reduce the influence of the measured string voltages on the computed current flows. The virtual switches in the strings of the electric drive are opened and/or closed by a switching logic.