Inverter Control Device for Low-Temperature Surge Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Inverters with semiconductor switching elements, such as IGBTs and MOSFETs, face reduced withstand voltage at lower temperatures, leading to potential damage from surge voltages when driven with constant input voltage, as existing control methods do not adequately address temperature-dependent voltage changes.
Innovation Solution
An inverter control device that includes a DC power supply, a voltage conversion unit, a temperature detection unit, and a control unit to adjust the output voltage based on ambient temperature, lowering the voltage as temperature decreases and setting an upper limit value that adapts with temperature changes to prevent overvoltage and protect the inverter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inverter is driven with constant input voltage, then the operation performance is maintained, but the semiconductor switching element may be damaged when ambient temperature is low
Solution Approach 1:
The patent implements dynamic adjustment of the input voltage to the inverter based on the detected temperature. The control device changes the input voltage level according to temperature conditions, making the system adaptable to varying thermal environments while protecting the semiconductor switching elements from damage due to surge voltages at low temperatures.
Solution Approach 2:
The patent changes the voltage parameter of the input power based on temperature detection. When the temperature is low, the control device reduces the input voltage to prevent the withstand voltage of the semiconductor switching element from being exceeded, thereby resolving the contradiction between maintaining operation performance and ensuring reliability across different temperature conditions.
2Reliability
If the input voltage is lowered when temperature is low, then the withstand voltage margin is maintained, but the operation efficiency decreases
Solution Approach 1:
The system dynamically adjusts the input voltage level based on real-time temperature detection. When temperature is low, the voltage is reduced to maintain the withstand voltage margin; when temperature is normal, the voltage is restored to optimal levels for efficient operation. This dynamic adaptation resolves the contradiction by optimizing both reliability and efficiency according to operating conditions.
Solution Approach 2:
The patent changes the voltage parameter adaptively based on temperature conditions. By adjusting the input voltage level to match thermal conditions, the system maintains adequate voltage margins at low temperatures while preserving high operation efficiency at normal temperatures, thus resolving the trade-off between reliability and productivity.
3Temperature
If the voltage conversion unit increases loss to raise temperature, then the inverter temperature is raised, but the energy consumption increases
Solution Approach 1:
The control device performs preliminary temperature detection before controlling the voltage conversion unit. By detecting the temperature in advance and proactively adjusting the input voltage accordingly, the system avoids the need to increase conversion loss to raise temperature, thereby preventing unnecessary energy consumption while still maintaining appropriate operating temperature and protection margins.
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 allows for safe operation of the inverter at lower temperatures by ensuring the tolerable surge voltage is maintained, improving efficiency and protecting the semiconductor switching elements across varying temperature ranges.
Implementation Method 1
a voltage conversion unit for converting a voltage level of a first DC voltage and supplying a second DC voltage to the inverter
Implementation Method 2
a temperature detection unit for detecting an ambient temperature of the inverter
Implementation Method 3
The control unit controls an operation of the inverter such that the second DC voltage is converted to an AC voltage
Data Source
AI summary
An inverter control device includes a DC power supply for outputting a first DC voltage, a voltage conversion unit for converting a voltage level of the DC voltage and supplying a first DC voltage to an inverter, a temperature detection unit for detecting an ambient temperature (element temperature) of the inverter, and a control device. The control device controls the voltage conversion unit such that the voltage VH lowers as the ambient temperature is lower, based on a temperature value representing a result of detection by a temperature sensor. A tolerable surge amount can thus sufficiently be ensured at a low temperature.