New Composition of UPS
News 2023年7月13日 33
The UPS uninterruptible power supply consists of a rectifier, an inverter, a storage battery, and a bypass switch. The principle and use of each component will be introduced below.
The rectifier can turn AC into DC to power the subsequent inverter and battery. Its performance index will affect the input index of UPS uninterrupted power supply. It mainly plays two functions: one is to rectify the alternating current to direct current and filter the load equipment or inverter; the other role is to provide the charging voltage for the battery, similar to the charger. The rectifier uses high frequency switch and silicon controller, which can control the output amplitude with the change of the external power supply, so the output amplitude stable voltage when the external power is changed.
When the city voltage is normal, the inverter does not work; when the abnormal city voltage occurs, the abnormal stable DC power or the battery stored DC can be converted into a relatively stable AC waveform with square wave and quasi wave sine wave.
The bypass switch can improve the reliability of UPS uninterrupted power supply and can withstand overload and short circuit. Because the IGBT pipe overload capacity of the UPS inverter is only 1.25 times, so when the power supply of the UPS system appears overload and short circuit phenomenon, the power supply can be automatically switched to the bypass through the bypass switch, so as to avoid the damage of the inverter and other parts of the power supply due to overload or short circuit. When transferred to the bypass power supply, the power is directly supplied to the load by the mains, there is enough time to disconnect the overload and short circuit circuit breaker, and then automatically switch to the inverter through the bypass switch. Bypass switches can be divided into two categories: one is the static bypass switches, For the touchless switch, Composed of thyristor switching devices, Is a pair of reverse parallel fast thyristor connected as a UPS uninterrupted power supply in the mains conversion to inverter power supply components, Reaction time of the fast thyristor is of a microsecond scale, So, it can realize uninterrupted power supply with zero load conversion time; the other type is dynamic bypass switch, For having a contact switch, Composed of a contactor, a circuit breaker, Using mechanical movements to complete the conversion, The conversion process is slower than the touchless switch, Can ages tens of milliseconds, Therefore, it is not suitable for important load situations.
The battery can be used to store the power of the UPS uninterrupted power supply system, and its capacity determines the time of emergency power supply. During the period of the mains voltage stabilization, the electric energy is converted into chemical energy through the charger and stored in the battery; when the mains voltage is abnormal, the chemical energy in the battery is converted into electric energy to provide electricity for the inverter.
Classification of UPS
The access mode of the inverter plays a decisive role in the performance of the uninterruptible power supply, so the access mode of the UPS can be divided into passive backup, online interactive and online type according to the access mode of the inverter.
Passive backup type
The passive backup uninterrupted power supply inverter is connected in parallel between the load and the mains power supply. When the city voltage voltage is stable, the inverter does not work and supplies electricity directly to the load; stable electricity to the load only when the city voltage is abnormal. When the mains voltage loses pressure, the battery becomes normal and stable AC energy output through the inverter circuit. Passive backup uninterruptible power supply is most suitable for protecting a single PC or workstation, which can solve power interruption, voltage subsidence and voltage surge common power faults.
The inverter of online interactive uninterruptible power supply is the same as the passive backup type, parallel between the load and the mains, only as a charger when the mains is normal, and automatically converted to the inverter when the mains is abnormal, so its reliability is high. When the mains voltage is 150~264V, the inverter can provide the general mains voltage processed by the ferromagnetic resonance regulator; when the mains voltage is below 150V or above 264V, the good sine wave voltage will be output to the load.
The online uninterruptible power supply filters the input city power, not only inverter into pure and stable 50Hz, 220V AC voltage output, but also charges the battery pack through the DC output of the charger. When the mains is normal, the battery is charged through the charger. When the mains is interrupted, the battery turns into normal AC output to output stable sine wave voltage to the load; automatic conversion is completed instantly, which can reliably output uninterrupted power supply to handle performance problems in mains.
UPS uninterruptible power supply breaks through the technical bottleneck in the era of analog circuit, digital control technology and high-precision master control technology ensure that it is 100% adapt to the complex power grid environment, and can set the working state according to the power needs of users.