PMSM Control Device Voltage Saturation Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing control devices for permanent magnet synchronous motors cannot effectively utilize surplus voltage from high-voltage power supplies to improve output torque in high-speed regions, leading to voltage saturation and reduced torque due to limitations in current command calculation methods.
Innovation Solution
A control device with separate power converters for each winding, utilizing a current command calculation unit that calculates voltage usage states to optimize current commands for both windings, ensuring effective use of high-voltage surplus voltage and preventing voltage saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If individual flux-weakening currents are set for low-voltage and high-voltage power converters based on their respective power supply voltages, then voltage saturation is suppressed in each system, but the surplus voltage of the high-voltage power supply cannot be effectively utilized to improve output torque in high-speed regions
Solution Approach 1:
The patent combines the control of low-voltage and high-voltage power converters by having the current command calculation unit calculate the second current command (for high-voltage converter) based on the first voltage usage state (from low-voltage converter). This merging allows effective utilization of the high-voltage surplus voltage while preventing voltage saturation in the low-voltage system, thereby improving output torque in high-speed regions.
Solution Approach 2:
The patent changes the control parameter from individual flux-weakening currents to a coordinated current command system where the second current command is calculated based on the first voltage usage state. This parameter change enables the high-voltage power converter to utilize its surplus voltage capacity while the low-voltage converter maintains voltage saturation suppression, achieving both reliability and power improvement.
2Device complexity
If the same current command is used for both low-voltage and high-voltage power converters, then device complexity is reduced, but voltage saturation occurs in the low-voltage system at high speeds, preventing desired current flow and reducing output torque
Solution Approach 1:
The patent introduces dynamic control where the second current command for the high-voltage power converter is adjusted based on the first voltage usage state from the low-voltage converter. This dynamic adjustment allows the system to adapt to varying voltage conditions, enabling the high-voltage converter to utilize its surplus capacity without causing saturation in the low-voltage system, thereby improving high-speed output torque.
Solution Approach 2:
The patent implements a feedback mechanism where the first voltage usage state (calculated from the low-voltage power converter's output voltage and power supply voltage) is used to determine the second current command for the high-voltage power converter. This feedback loop ensures that the high-voltage converter's current command is optimized based on the low-voltage system's voltage saturation risk, preventing saturation while maximizing power utilization.
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 significantly improves output torque in high-speed regions by effectively utilizing high-voltage surplus voltage, maintaining torque levels and preventing voltage saturation, thereby enhancing motor performance.
Implementation Method 1
a first power converter configured to apply a voltage to the first winding; a second power converter configured to apply a voltage to the second winding
Implementation Method 2
permanent magnet synchronous motor having a first winding and a second winding
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Provided is a control device for an electric motor including a first winding and a second winding, the control device including: a first power converter configured to apply a voltage to a first winding; a second power converter configured to apply a voltage to a second winding; a first power supply circuit configured to supply power to the first power converter; a second power supply circuit configured to supply power to the second power converter; a current command calculation unit; a first current control unit; and a second current control unit, in which the second power supply circuit is configured to supply power at a voltage higher than a voltage of the first power supply circuit, and in which the current command calculation unit is configured to calculate a first voltage usage state, which is an indicator value correlated with a magnitude of the output voltage of the first power converter with respect to a power supply voltage output at a time of supply of power by the first power supply circuit, and calculate the second current command based on the first voltage usage state.