Motor Controller Charging Discharge Circuit Voltage Step-Up
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Solution Overview
Problem
Conventional motor controllers are limited in their ability to discharge electrical energy from a capacitor to a DC link, as they can only supply energy when the capacitor voltage is equal to or higher than the DC link voltage, leading to inefficient energy utilization and increased capacitance requirements.
Innovation Solution
A motor controller with a charging/discharging control circuit that performs step-up and step-down operations, allowing energy transfer from the capacitor to the DC link even when the capacitor voltage is lower, by switching to step-up operation when the discharge current decreases, thereby enabling efficient energy utilization and reducing capacitor capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the capacitor voltage is required to be equal to or higher than the DC link voltage for energy discharge, then the discharge control is simple, but the energy utilization is inefficient and the capacitance requirement increases
Solution Approach 1:
The patent changes the operating parameters of the capacitor discharge process by introducing a voltage conversion mechanism. The capacitor can discharge at voltages lower than the DC link voltage, and the voltage is converted to match the DC link voltage through a conversion circuit. This parameter change enables efficient energy utilization without requiring the capacitor to maintain high voltage, thus reducing the required capacitance.
Solution Approach 2:
The patent introduces a voltage conversion circuit as an intermediary between the capacitor and the DC link. This intermediary component enables energy transfer even when the capacitor voltage is lower than the DC link voltage by converting the voltage levels. The conversion circuit acts as a mediator that resolves the voltage mismatch, allowing efficient energy utilization while reducing capacitance requirements.
2Speed
If the capacitor can only be discharged up to the DC link voltage, then the voltage control is simple, but the response to load change is deteriorated
Solution Approach 1:
The patent implements dynamic voltage conversion that adapts to load changes. The voltage conversion circuit can dynamically adjust its operation based on the capacitor voltage and DC link voltage conditions. During acceleration, the capacitor discharges and the conversion circuit dynamically adjusts to maintain proper voltage levels, enabling fast response to load changes while managing control complexity through adaptive control strategies.
3Quantity of substance
If the capacitor voltage is lower than the DC link voltage, then the capacitance requirement is reduced, but energy cannot be supplied from the capacitor to the DC link in conventional systems
Solution Approach 1:
The patent fundamentally changes the voltage parameter relationship between capacitor and DC link. Instead of requiring capacitor voltage to be higher than DC link voltage, the system uses a voltage conversion circuit to enable energy transfer when capacitor voltage is lower. This parameter change allows smaller capacitance values while maintaining full energy transfer capability.
Solution Approach 2:
The voltage conversion circuit serves as an intermediary that enables energy transfer from the capacitor to the DC link even when the capacitor voltage is lower. This intermediary component converts the voltage levels to match, allowing energy transfer that would otherwise be impossible in conventional direct connection systems.
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 motor controller effectively utilizes electrical energy stored in the capacitor, allowing energy transfer regardless of voltage differences, enhancing energy supply and reducing the required capacitance for the same regenerative energy, thus improving response to load changes.
Implementation Method 1
a capacitor and a charging/discharging control circuit that are connected in parallel with the DC link so that electrical energy is supplied from the DC link to the capacitor and vice versa
Implementation Method 2
the charging/discharging control circuit includes a discharge circuit that performs a step-up operation of raising a voltage of the capacitor while the electrical energy charged in the capacitor is discharged
Data Source
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AI summary
A motor controller capable of effectively utilizing electrical energy accumulated in a capacitor and achieving a reduction in capacitance of the capacitor. The motor controller includes a converter that receives an input AC voltage and performs AC-to-DC power conversion thereon, an inverter that receives DC power and performs DC-to-AC conversion thereon, and a capacitor and a charging/discharging control circuit connected in parallel with a DC link between the converter and the inverter. Electrical energy is supplied from the capacitor to the DC link via the charging/discharging control circuit. The charging/discharging control circuit has a circuit for discharging electrical energy accumulated in the capacitor and for stepping up a voltage of the capacitor when discharging the electrical energy.