UPS (Uninterruptible Power Supply) means uninterrupted power supply system, which can provide continuous and stable power to the load. With the popularization of computers, precision electronic instruments and other electrical equipment, and the increasing demand for power quality in important places such as banks, telecommunications, and hospitals, UPS has been widely used and has gradually developed into a highly reliable, high-performance, and highly automated local power supply center. However, with the large-scale use of UPS, the pollution caused by UPS to the power grid and the environment has gradually become apparent. In today's increasingly environmentally conscious world, people are constantly researching and developing new environmental protection technologies to replace the original technologies, so that UPS can gradually become a truly green power source. Xiamen Kehua Hengsheng Co., Ltd. (hereinafter referred to as Kehua Company) has long been committed to the technological development and upgrading of energy-saving and environmentally friendly UPS, and advocates the new concept of UPS. From the perspective of Kehua UPS, the meaning of green is high efficiency, low noise, low pollution and low radiation, which are specifically manifested in: (1) Energy saving. This is determined by high efficiency, of course, mainly refers to saving electrical energy: first, the host has high efficiency, saving UPS input power; second, the host generates little heat, saving the power used for environmental regulation such as air conditioning. (2) No pollution to the natural environment. Using raw materials with minimal environmental impact, such as RoHS compliant raw materials and components, achieves zero emissions of factory waste. At the same time, saving electricity will inevitably save energy resources (such as coal) used for power generation equipment, thereby reducing the emission of harmful gases such as carbon dioxide. (3) Does not pollute the power grid environment. The input power factor is approximately equal to 1, there is no reactive current input, no interference with the power grid, and the input harmonic current is reduced to the minimum. Reduces electromagnetic compatibility characteristics, does not interfere with the load, and achieves harmonious coexistence between people and equipment. (4) Adopts energy-saving power supply technologies, such as power factor correction technology and EMC electromagnetic compatibility technology. (5) Develops pollution-free energy systems, such as solar energy and wind energy. Power Factor Correction Technology Currently, many types of UPS products use non-linear power input, with an input power factor generally between 0.7 and 0.85. The harmonic distortion of the input current generated by the rectifier can reach 30% to 50%. This will cause interference to the voltage waveform of the power grid, reduce the load capacity of the power grid wiring, and in severe cases may lead to oscillation of the power supply system or abnormal operation of other equipment. Therefore, power factor correction and current harmonic suppression technologies can be used to improve the input power factor and reduce pollution to the mains power. For high-frequency UPS systems, Kehua generally uses dedicated ICs, CPUs, and DSPs to achieve AC power factor correction and current harmonic suppression, resulting in an input power factor of over 0.95 and current harmonics below 15%. For larger UPS systems, Kehua can use twelve-pulse and active power factor correction, achieving input harmonic distortion below 5% and a power factor of 0.99, effectively reducing grid load and realizing energy-saving and environmentally friendly UPS power input design. EMC Electromagnetic Compatibility Design In green power supply, electromagnetic compatibility (EMC) is an important metric, referring to the ability of electronic equipment to operate normally in an electromagnetic environment. If EMC issues are addressed during product development, and the user's investment cost is calculated as 1, the cost of addressing it during model development might be 10, the cost during mass production might reach 100, and the cost during on-site installation might be thousands or even impossible. To effectively eliminate interference from the UPS itself, Kehua uses EMI filters and shielding devices to address relatively easy-to-handle radiated interference. Each circuit unit within the cabinet of Kehua's high-power UPS has independent shielding measures, providing excellent electromagnetic shielding. This prevents leakage of its own electromagnetic waves from interfering with surrounding equipment and avoids interference from external radiation, ensuring reliable UPS operation. High-performance EMI filters are designed at the input and output terminals to effectively filter radio waves in specified bands, eliminating spikes and noise in the power grid. The UPS's anti-interference capability is primarily reflected in the control circuit's immunity. Kehua uses advanced DSP digital control chips to directly generate high-frequency PWM waves to control the UPS inverter, simplifying the UPS control circuit and improving control flexibility and stability. The use of fully digital control technology avoids the inherent hardware parameter drift defects of analog control, ensuring product consistency and reliability. Simultaneously, all I/O ports are technically processed, with a well-designed PCB layout and reasonable electromagnetic shielding measures effectively preventing external interference to the digital system. This ensures reliable power protection for network loads while achieving safety and environmental protection functions, guaranteeing harmony between the UPS product, the environment, and people. MMBM Battery Management Technology The battery is the heart of a UPS. Once the battery fails, even the best UPS cannot provide a clean and stable uninterrupted power supply. Current UPS systems generally use maintenance-free lead-acid batteries. While this overcomes the drawback of ordinary batteries requiring periodic water replenishment, from an environmental perspective, these batteries not only generate heat and emit acid fumes, but also present significant challenges in disposal at the end of their lifespan. Effectively reducing and avoiding battery-related environmental pollution is a key issue for green UPS systems. Kehua's proprietary intelligent multi-mode battery management technology includes phased charging technology, periodic battery testing and activation technology, battery balance detection technology, and battery discharge fuzzy regulation technology. This ensures minimal environmental impact during charging and use, effectively extends battery life, and reduces pollution from discarded batteries. Intelligent Fan Speed ​​Control Technology: The main noise sources in a UPS come from high-frequency components during inverter switching, transformer noise, and fan noise. For high-quality UPS systems, modulation frequencies above 20kHz are used in the design, exceeding the human ear's ability to distinguish them, resulting in virtually no audible audio noise. Therefore, intelligent fan speed control is crucial to the overall noise level of the product. Currently, Kehua's high-end UPS systems perform exceptionally well in this regard, exhibiting virtually no noticeable audible audio noise during short-term operation under low loads, avoiding the annoying fan noise of older UPS systems.