Air conditioner and rectifier
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Solution Overview
Problem
Existing air conditioning systems face challenges in effectively suppressing harmonic current while controlling output voltage, particularly in high-power applications, leading to inefficiencies and increased costs due to the need for large reactors and voltage unbalance issues with capacitors.
Innovation Solution
The system employs a rectifier with multiple capacitors connected in series, a switching device for current control, and a controller that detects output voltage and current to adjust the switching device's duty cycle, ensuring stable voltage distribution and harmonic suppression by dividing the output voltage across capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a double voltage rectifier with PFC technology is used to suppress harmonic current and boost input voltage, then the output voltage control and harmonic suppression are improved, but the device complexity and cost increase due to large electrical and temperature loads requiring high-power components
Solution Approach 1:
The rectifier is divided into multiple independent full-bridge rectifier modules (first full-bridge rectifier module, second full-bridge rectifier module, etc.), each handling a portion of the rectification task. This segmentation allows each module to operate with reduced power stress, simplifying individual module design while maintaining overall system performance for harmonic suppression and voltage boosting.
Solution Approach 2:
A voltage balancing circuit is introduced as an intermediary component between the series-connected capacitors. This circuit actively monitors and balances the voltage across each capacitor, enabling the system to achieve proper voltage distribution without requiring overly complex control mechanisms in the main rectifier path, thus resolving the contradiction between harmonic suppression effectiveness and device complexity.
2Power
If capacitors are connected in series to achieve double voltage output, then the output voltage is improved, but voltage unbalance occurs between capacitors leading to reliability issues
Solution Approach 1:
The voltage balancing circuit implements continuous feedback monitoring of the voltage across each series-connected capacitor. By detecting voltage differences and actively adjusting the charging/discharging of individual capacitors through switching devices, the system maintains voltage balance across all capacitors, ensuring reliable operation while achieving the desired double voltage output.
3Power
If high-voltage components are used to handle the boosted voltage, then the output voltage capability is improved, but the cost and device complexity increase
Solution Approach 1:
By segmenting the rectifier into multiple full-bridge modules with series-connected capacitors, each component only needs to handle a portion of the total voltage stress. This allows the use of lower-voltage-rated, more cost-effective components throughout the system while still achieving high overall output voltage capability through the series configuration.
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 approach allows for efficient harmonic current suppression and stable voltage control, reducing the need for high-voltage components and minimizing energy losses, while enabling the use of lower-standing voltage devices for cost-effectiveness.
Implementation Method 1
a rectifier including a plurality of capacitors connected in series to each other, a switching device configured to control a flow of current supplied to the respective capacitors to charge or discharge the plurality of capacitors
Implementation Method 2
a rectifier including a plurality of capacitors connected in series to each other, a switching device configured to control a flow of current supplied to the respective capacitors to charge or discharge the plurality of capacitors
Data Source
AI summary
Disclosed herein is an air conditioner including: a rectifier including a plurality of capacitors connected in series to each other, a switching device configured to control a flow of current supplied to the respective capacitors to charge or discharge the plurality of capacitors, a voltage detector configured to detect an output voltage of the plurality of capacitors, and a current detector configured to detect the current; and an inverter configured to generate alternating current by receiving an output voltage of the rectifier.