Capacitorless Inverter Surge Suppression in Multiphase Supply Circuits
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Solution Overview
Problem
Capacitorless inverter control systems with small capacitance are vulnerable to lightning surges, leading to potential damage due to excessive voltage increases, as they rely on components with breakdown voltages around 600 V, which can be exceeded during surges.
Innovation Solution
Incorporating a peak-value suppressor, diodes, and a bypass circuit with resistive and capacitive elements in parallel with the capacitor, along with an inductor connected in series to the capacitor, to manage and suppress voltage increases during lightning surges, ensuring the capacitorless inverter control operates effectively even with small capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a small capacitance capacitor is used in capacitorless inverter control, then circuit miniaturization and cost reduction are achieved, but vulnerability to lightning surges increases causing voltage spikes that can damage the inverter circuit
Solution Approach 1:
A surge suppressor circuit is introduced as an intermediary component between the power supply and the capacitorless inverter control system. This mediator absorbs and redirects lightning surge energy, preventing direct damage to the inverter circuit while allowing the small capacitance capacitor to maintain its miniaturization function.
Solution Approach 2:
The surge suppressor circuit provides beforehand cushioning by being pre-configured to absorb and dissipate lightning surge energy before it can reach the vulnerable capacitorless inverter control system. This protective measure is in place before any surge event occurs, cushioning the system against potential damage.
2Ease of manufacture
If capacitorless inverter control is implemented without smoothing circuit, then power factor correction and harmonic suppression are achieved, but protection against lightning surges is lost
Solution Approach 1:
A surge suppressor circuit is introduced as an intermediary component between the power supply and the capacitorless inverter control system. This mediator absorbs and redirects lightning surge energy, preventing direct damage to the inverter circuit while allowing the small capacitance capacitor to maintain its miniaturization function.
Solution Approach 2:
The harmful function of lightning surge protection is extracted from the main capacitorless inverter control system and implemented as a separate, dedicated surge suppressor circuit. This allows the inverter control system to remain simple and capacitorless while the extracted protection function handles surge suppression independently.
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 effectively prevents voltage increases during lightning surges, protecting the inverter circuit and maintaining high power factor operation by controlling the rectified voltage within safe limits, even with small capacitance values, thus enabling miniaturization and cost reduction while ensuring system reliability.
Implementation Method 1
The diode bridge 2 performs full-wave rectification on the AC voltage Vin
Implementation Method 2
The capacitor 31 whose both ends are supplied with output from the diode bridge 2. The capacitance C of the capacitor is small
Implementation Method 3
An inductance parasitic to the power supply system 1 is indicated as an inductor 12 connected to the AC power supply 13 in series
Data Source
AI summary
A multiphase current supplying circuit according to the present invention includes a diode bridge, an intervening circuit, an inverter, a control circuit, and a lightning arrester. The diode bridge is connected to a single-phase AC power supply system via the lightning arrester, and performs full-wave rectification on a single-phase AC voltage. The intervening circuit includes a capacitor and an inductor, and is constituted by a choke input type low-pass filter. More specifically, one end of the inductor and one end of the capacitor are connected, output from the diode bridge is received between the other end of the inductor and the other end of the capacitor, and a rectified voltage generated at both ends of the capacitor is output to the inverter.