Medical Uninterruptible Power Solution

With the rapid development of medical technology, medical equipment is constantly being updated, and some high-tech, sophisticated and sophisticated equipment should be used more and more in clinical applications. And these advanced equipments have particularly high requirements for power supply systems, and various sensitive electronic components in the equipment need continuous and stable uninterruptible power supply. In particular, some imported equipment are designed in accordance with international standard power grid environmental indicators. These equipments can work normally within the standard voltage range, with fewer failures and long life. However, the use in China's power grid conditions will lead to instability, high failure rate, shortened life and so on. The main reason is that there are many unstable factors in China's current public power system. For example, the power grid voltage is sometimes high, low, surge, shock, and sudden power failure, which seriously affects the safe operation of medical equipment and even damages the equipment, causing serious economic losses. Therefore, UPS (Uninterruptible power system) has become the key to protecting important equipment. At present, most hospitals will equip some of the more important equipment with corresponding UPS . For example, some hospitals are equipped with UPS for equipment such as MR, CT, color Doppler ultrasound, biochemical analyzer, blood cell counter, etc. These UPS have become protection for these important medical equipment. Therefore, how to use and maintain the UPS is of great economic and practical significance.

1. Choice of UPS type

UPS uninterruptible power supply is divided into three types: backup type, online interactive type and online type. When the mains power supply is normal, the backup UPS provides the load with a sine wave voltage that has been slightly stabilized to the mains voltage. When the mains power supply is abnormal, it provides a stable square wave power to the load . The online interactive UPS provides the load with a sine wave voltage that has been slightly stabilized to the mains voltage when the mains power supply is normal. Only when the mains power supply is abnormal, does it provide inverters to the user load Sine wave power supply. Neither the backup type nor the online interactive UPS can provide a standard sine wave voltage to the load online in real time. However, the online UPS is different. As long as there is a load, the inverter will always work. It provides the load with a reliable and stable sine wave power after the inverter, the voltage stability is better than the backup and online interactive UPS, and the output voltage The instantaneous response characteristics are good, with a good "purification" function and safety protection function, the pressure resistance is very strong. Therefore, in areas with relatively large fluctuations in mains power and medical equipment that requires high power supply quality, an online UPS with good voltage stability should be used. Hospital equipment is basically equipped with an online UPS. In principle, the backup UPS can only be used in some devices that do not require high output waveforms, such as office equipment, and cannot drive inductive loads. For example, a hospital's color Doppler ultrasound was initially equipped with a 5KVA backup UPS, and it was found that there were always strip artifacts on the screen. Later, after replacing an online UPS, the artifacts disappeared. The company's Shanke New Energy Technology (Shenzhen) Co., Ltd. products have online, backup UPS uninterruptible power supply.

2. Determination of UPS load

The standard capacity of the UPS is its standard power. In fact, the load of the UPS is usually a non-linear load, which changes with the change of the load power factor. If the output characteristics of the UPS are not good, the output voltage will drop and the voltage stability will decrease. Affect the safe work of the load. Therefore, the capacity of the UPS with non-linear loads should be considered when determining the capacity of the UPS, that is, the actual load capacity is determined according to the rated power and power factors provided by the UPS to avoid the UPS from working abnormally or damaging the UPS due to load transition Inverter. In other words, a UPS with a rated output power of 1KVA does not necessarily drive a 1KVA load. In order to extend the service life of the UPS, the UPS should not be operated under full load for a long time. The backup UPS generally selects a load of 60%~70% of the rated power, and the online UPS generally selects a load of 70%~80% of the rated power. At the same time, the UPS should not be operated under excessive light load for a long time. The battery power supply time is mainly affected by factors such as battery capacity, load size, ambient temperature, connected load, and battery discharge cut-off voltage.

3. Proper use of UPS host

Please read the instruction manual carefully before using the UPS. UPS is suitable for long-term uninterrupted work, and it is not suitable to switch on and off every day or often. If the load does need to be powered off, an air switch can be connected between the output of the UPS and the load. Turn off the air switch to disconnect the power supply of the load. The UPS should be cleaned and dedusted regularly (six months) to prevent the dust from entering the chassis and affecting the heat dissipation of the electronic components, which can damage the electronic components. Regular inspection and replacement of the UPS cooling fan and large-capacity capacitors should be done to prevent damage to other components.

 4. Maintenance of UPS battery

 Because the UPS uses maintenance-free batteries, each 12V, basically use the serial working mode, generally ranging from several to dozens of series. As long as the internal resistance of one of the batteries is increased or damaged, the entire set of batteries cannot be powered according to the designed capacity, which may cause damage and power outages. Therefore, the battery must be regularly checked and maintained.

4.1 The newly purchased UPS uninterruptible power supply or the newly replaced battery must be fully charged before the battery is used. Since the UPS is produced from the production to the user's installation and use, it generally takes a period of time. During this time, the battery reduces its power due to its own discharge. , Can not reach the specified delay time, in order to ensure the normal service life, the initial use must be charged for several hours according to the requirements in the product manual.

4.2 Ambient temperature Use of the battery should pay attention to the ambient temperature. Generally, the battery should be used in the ambient temperature between 0 ℃ -30 ℃. If the temperature is too high, the service life of the battery will be greatly shortened . For the sealed maintenance-free battery, when the ambient temperature exceeds 25 ° C, each 10 ° C increase in temperature will reduce the service life of the battery by half. If the temperature is too low, the actual releasable capacity of the battery will also be greatly reduced.

4.3 If the battery pack is charged for a long period of time, its internal resistance will increase or be permanently damaged. Therefore, avoid placing the battery in a charged state for a long time. For UPS operating in areas where there is rarely long power outages, it must be every 3 months It is necessary to discharge it artificially once, that is, turn off the AC input power of the UPS, and the UPS is in battery mode to supply power, so that the battery discharge current is greater than 0.1 A.

4.4 Avoid deep discharge of the battery or long-term low-current over-charge discharge. When the battery discharges at a low current, the voltage drop from the battery terminal is slower than that at a large current. When the UPS protection is shut down, the battery has actually been discharged, causing battery failure or shortened life. If the battery is deeply discharged, its life will also be affected. When the battery pack is discharged, it usually takes 8 hours to 12 hours to charge before the battery can be fully charged