AC Motor Driving Apparatus Power Compensation Control
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Solution Overview
Problem
Conventional AC motor driving apparatuses face challenges in reliable power compensation, especially when power demand is constant in either power running or regeneration states, leading to power shortages or excesses, which can be costly and inefficient due to the need for large-capacity power storage devices.
Innovation Solution
An AC motor driving apparatus with a power compensator that includes a step-up/down circuit, a power storage device, and a control device performing power compensation and adjustment processes to maintain power balance within predetermined limits, allowing for reliable power compensation even with non-large-capacity power storage devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power compensator uses large-capacity power storage device to ensure sufficient power during continuous power running, then power supply reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent implements dynamic power storage adjustment by continuously monitoring the operation state (power running vs. regeneration) and adapting the power storage device capacity accordingly. The control device dynamically determines whether to charge or discharge the power storage device based on real-time operational conditions, replacing the static large-capacity design with a dynamic adjustment mechanism that ensures reliability only when necessary.
Solution Approach 2:
The patent changes the operational parameters of the power storage device based on operation state. During power running, the system ensures sufficient charge; during regeneration, it absorbs excess power. This parameter-based control (charge/discharge states) allows the use of smaller power storage devices while maintaining reliability, as the system adapts its power management strategy to match actual operational demands.
2Reliability
If power compensator uses large-capacity power storage device to absorb excess power during regeneration, then power balance is improved, but device complexity and cost increase
Solution Approach 1:
The system dynamically adjusts power storage capacity utilization based on operation state. During regeneration, the control device activates charging mode to absorb excess power; during power running, it switches to discharge mode. This dynamic state-based control allows the power storage device to be sized for typical rather than peak demands in both directions, reducing overall capacity requirements while maintaining power balance.
Solution Approach 2:
The power compensator uses its own power storage device to self-regulate power balance by absorbing excess power during regeneration and supplying power during power running. This self-service mechanism eliminates the need for external power balancing infrastructure, reducing system complexity while maintaining reliable power balance through intelligent control of the power storage device.
3Power
If DC power supply capacity is designed for short-time rated output, then motor performance is improved, but power supply facility utilization deteriorates
Solution Approach 1:
The control device performs preliminary charging of the power storage device during regeneration periods before peak power running demands occur. By anticipating future power needs and pre-charging the storage device, the system enables the DC power supply to be sized for average rather than peak demands, improving facility utilization while ensuring power availability when needed through the pre-charged storage device.
Solution Approach 2:
The power storage device acts as an intermediary between the DC power supply and the motor. It buffers the mismatch between average power supply capacity and peak power demand, allowing the DC power supply to be sized for average utilization while the power storage device handles peak demands during power running. This intermediary function resolves the contradiction between motor performance and power supply facility 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
Ensures reliable power compensation in AC motor driving systems by dynamically adjusting power storage within the power allowance, effectively managing power demand in both power running and regeneration states without requiring large-capacity storage devices, thus optimizing system efficiency and reducing costs.
Implementation Method 1
a power storage device 15 that absorbs/discharges power
Implementation Method 2
a step-up/down circuit 10 that converts a voltage level
Data Source
AI summary
In the case where DC power from a DC power supply is converted to AC power by an inverter and supplied to an AC motor, a power compensator is connected in parallel with a DC power input portion of the inverter, and a control device of the power compensator charges/discharges a power storage device to perform a power compensation process A when power demand for the AC motor exceeds a predetermined value, and takes into account power allowance which can be inputted and outputted from the DC power supply to the power storage device and performs a power storage adjustment process B of performing auxiliary charge of the power storage device within the range of the power allowance when the power compensation process A is unnecessary.