Motor Driving Apparatus Regenerative Power Recovery
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Solution Overview
Problem
Existing motor driving apparatuses do not effectively reduce the total power supply requirements, as they fail to utilize regenerative power during motor deceleration, leading to increased demands on the power supply capacity.
Innovation Solution
A motor driving apparatus with a PWM converter and a power storage device, where the PWM converter control circuit manages power supply during acceleration and deceleration phases, allowing the power storage device to recover and reuse regenerative power, thereby reducing the power needed from the power supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the voltage of the power storage device is maintained constant at all times, then the power storage device can provide stable buffering capability, but the regenerative power during motor deceleration cannot be stored and is either returned to the power supply or consumed by resistors
Solution Approach 1:
The patent applies dynamics by transitioning from static constant voltage maintenance to dynamic voltage control. The power storage device voltage is allowed to vary within a predetermined range during motor deceleration to enable regenerative power storage, while maintaining stability during motor acceleration. This dynamic adjustment resolves the contradiction between voltage stability and regenerative energy recovery.
Solution Approach 2:
The patent changes the voltage parameter of the power storage device from a fixed constant value to a variable parameter that adapts to different motor operating states. During acceleration, voltage is maintained constant; during deceleration, voltage varies within a predetermined range to accept regenerative power. This parameter change enables the system to recover energy that would otherwise be lost.
2Power
If a power storage device is used to suppress power peaks during motor acceleration, then the buffering capability is improved, but the total amount of power that has to be supplied from the power supply does not become smaller
Solution Approach 1:
The patent implements continuity of useful action by creating a closed-loop energy management system. Regenerative power during deceleration is stored in the power storage device and continuously reused during subsequent acceleration phases, eliminating the need for continuous fresh power supply and reducing total power consumption over the complete motor cycle.
Solution Approach 2:
The patent recovers regenerative power that would otherwise be discarded during motor deceleration. By allowing the power storage device voltage to vary and accept regenerative power, the system captures and stores energy that would normally be lost, then reuses it during acceleration, thereby reducing the total power that must be supplied from the external power source.
3Loss of energy
If the power storage device voltage is allowed to vary during motor acceleration, then regenerative power can be recovered during deceleration, but the control complexity increases
Solution Approach 1:
The patent segments the motor operation into distinct phases (acceleration and deceleration) with different control strategies. During acceleration, the power storage device voltage is maintained constant at a reference value. During deceleration, the voltage is allowed to vary within a predetermined range. This segmentation simplifies control by applying different rules to different operational phases rather than using a complex continuous control algorithm.
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 solution reduces the total power supply requirements by allowing the power storage device to recover and reuse regenerative power, easing the strain on the power supply capacity and optimizing energy usage.
Implementation Method 1
a power storage device, provided between the PWM converter and the PWM inverter, that can store electric power in an amount capable of driving the motor
Implementation Method 2
a PWM converter which, under PWM (Pulse Width Modulation) control, converts AC power supplied from a power source into DC power and vice versa
Implementation Method 3
a PWM inverter which converts the DC power output from the PWM converter into variable-frequency AC power and vice versa, and which drives a motor with the variable-frequency AC power
Implementation Method 4
allowing at least a portion of regenerative power occurring in the motor during the deceleration control period to be recovered by the power storage device
Data Source
AI summary
When the output of motor reaches or exceeds a predetermined value during acceleration of the motor, the control target value of the DC link voltage which is the voltage of a power storage device is gradually lowered in corresponding relationship to the motor output. When the motor enters a constant speed control mode, the DC link control target value is maintained at a constant level. When the motor enters a deceleration control mode, the DC link control target value is gradually raised in corresponding relationship to the motor output, and regenerative power is recovered by the power storage device and reused in the next control cycle.