Parallel Inverter Control to Extend DC Smoothing Capacitor Life
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Solution Overview
Problem
Conventional power converting apparatuses experience accelerated aging and reduced lifespan of smoothing units due to high electric current, with existing solutions failing to effectively extend the lifespan by using multiple devices driven by a single converter and multiple inverters.
Innovation Solution
A power converting apparatus configuration where two or more devices are driven by one converter with multiple inverters connected in parallel, featuring a control unit that reduces electric current in the smoothing unit by synchronizing the operation of the inverters with the load units, thereby minimizing current pulsation and stress on the capacitor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single converter with smoothing unit drives one inverter, then power conversion is simple, but large electric current flows in the smoothing unit causing accelerated aging and shortened lifespan
Solution Approach 1:
The patent merges multiple inverters (first inverter and second inverter) to share a single converter and smoothing unit. This combination allows the smoothing unit to serve multiple loads simultaneously, reducing the current burden on each individual inverter-smoothing unit pair and extending the smoothing unit's operational lifespan.
Solution Approach 2:
The smoothing unit is designed to serve multiple functions by supporting both the first inverter and second inverter. This multi-functionality allows a single smoothing unit to replace what would traditionally require two separate smoothing units, reducing overall system complexity while extending the unit's effective service life through load sharing.
2Duration of action of stationary object
If multiple inverters are connected to one converter, then smoothing unit lifespan is extended, but control complexity increases
Solution Approach 1:
The control unit implements feedback control by monitoring the operation states of both inverters and adjusting their control parameters accordingly. This feedback mechanism enables coordinated operation of the multiple inverters sharing the single converter, managing control complexity through active monitoring and dynamic adjustment.
Solution Approach 2:
The control system dynamically adjusts the operation of each inverter based on real-time load conditions and converter state. This dynamic control allows the system to optimize current distribution and operational parameters, managing the complexity of multiple inverters through adaptive rather than static control strategies.
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 configuration extends the lifespan of the smoothing unit by reducing current flow and stress, allowing for the use of less expensive capacitors while maintaining efficient power conversion and reducing the overall cost of the apparatus.
Implementation Method 1
a converter rectifying a power supply voltage applied from an alternating-current power supply and, if necessary, boosting the power supply voltage
Implementation Method 2
boosting the power supply voltage
Implementation Method 3
a smoothing unit connected to an output end of the converter
Implementation Method 4
the first inverter converting power outputted from the converter and the smoothing unit into a first alternating-current power
Data Source
AI summary
A power converting apparatus includes a converter, a smoothing unit, inverters, and a control unit. The inverters are connected to the converter, the inverters being in parallel connection with each other. The inverter converts power output from the smoothing unit into a first alternating-current power, and outputs the first alternating-current power to a device in which a motor is installed. The inverter converts power outputted from the smoothing unit into a second alternating-current power, and outputs the second alternating-current power to a device in which a motor is installed. The control unit controls an operation of the converter and the inverters to reduce a current flowing in the smoothing unit and concurrently controls an operation of the inverter in accordance with an operation state of the inverter and a load unit including the device.