Motor Drive Device Dynamic Voltage Limitation Strategy
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Solution Overview
Problem
Existing drive devices impose uniform limitations on motor load factors, leading to potential overheat of inverter elements when induced voltage is higher than input voltage and insufficient driving force when it is lower, due to inadequate consideration of rotation speed.
Innovation Solution
A drive device configuration that dynamically adjusts motor limitations based on the comparison between induced voltage and input voltage, imposing a larger limitation when induced voltage is higher and a smaller limitation when it is lower, using a control device to manage field weakening control and prevent overheat or driving force shortages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a uniform limitation is imposed on the load factor of the motor, then the inverter element overheating is suppressed to some extent, but the limitation becomes insufficient or excessive depending on the rotation speed, causing either inverter element overheat or motor driving force shortage
Solution Approach 1:
The patent applies dynamics by transitioning from a static uniform load factor limitation to a dynamic limitation strategy that adapts to changing operating conditions. The control device dynamically determines whether to impose a first limitation (when induced voltage exceeds input voltage) or a second limitation (when induced voltage does not exceed input voltage) based on real-time voltage comparison, allowing the limitation strategy to flexibly respond to different rotation speeds and voltage conditions.
Solution Approach 2:
The patent implements parameter changes by modifying the load factor limitation parameter based on the relationship between induced voltage and input voltage. When the induced voltage exceeds the input voltage, a first limitation value is applied; when it does not exceed, a second limitation value is applied. This parameter change approach allows the system to optimize both inverter temperature control and motor driving force across different operating conditions.
2Speed
If field weakening control is performed to handle high induced voltage, then the motor can operate at higher speeds, but d-axis current flows causing inverter element overheat
Solution Approach 1:
The patent applies preliminary anti-action by preemptively imposing a stricter first limitation on the load factor when the induced voltage exceeds the input voltage, before the inverter element temperature can rise to dangerous levels. This preventive measure counteracts the potential harmful effect of field weakening control causing inverter element overheat by limiting the d-axis current in advance.
Solution Approach 2:
The patent changes the load factor limitation parameter based on the voltage relationship. When induced voltage exceeds input voltage (indicating field weakening control is needed for high-speed operation), a first limitation value is applied to restrict d-axis current and prevent inverter element overheat. This parameter change allows the system to balance high-speed operation capability with inverter element temperature control.
3Temperature
If a strict limitation is imposed on the load factor to prevent inverter element overheat, then inverter element temperature is controlled, but motor driving force becomes insufficient
Solution Approach 1:
The patent applies local quality by imposing different limitation strategies in different operating conditions. Instead of a uniform limitation, the system applies a first limitation when induced voltage exceeds input voltage (high-speed field weakening region) and a second, less restrictive limitation when induced voltage does not exceed input voltage (normal operating region). This localized approach ensures adequate driving force is maintained in normal operation while preventing overheat in high-speed conditions.
Solution Approach 2:
The patent uses dynamics to adapt the limitation strategy to current operating conditions. The control device dynamically switches between first and second limitation values based on the real-time comparison between induced voltage and input voltage, allowing the system to optimize the balance between inverter element temperature control and motor driving force for each specific operating point.
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 effectively suppresses overheat of inverter elements and prevents driving force shortages by tailoring motor limitations to the specific voltage conditions, ensuring a more appropriate and balanced operation.
Implementation Method 1
a motor configured to generate an induced voltage according to a rotation speed
Data Source
AI summary
There is provided a drive device configured to impose a more appropriate limitation on driving of a motor. The drive device comprises a motor configured to generate an induced voltage according to a rotation speed, and an inverter configured to drive the motor. Upon satisfaction of a predetermined condition to impose a limitation on driving of the motor, the drive device performs a drive limitation that imposes a larger limitation on driving of the motor when the induced voltage of the motor is higher than an input voltage that is input from a power storage device side to the inverter, compared with a limitation imposed when the induced voltage of the motor is equal to or lower than the input voltage.