Jiangsu EPS emergency supply Manufacturer: Jiangsu EPS Power Supply Price
1.1 Classification of EPS emergency power supply: At present, there are many brands of EPS emergency power supply in the market, and the control methods adopted by everyone in the design are different, but according to the type and size of the load, there are three types: one is single-phase EPS emergency power supply mainly used for emergency lighting and accident lighting, ------ YJ series; The second is for air conditioner 、 Elevator. 、 Rolling shutter door , exhaust fan, water pump and other inductive loads or hybrid three-phase series EPS ------ YSJ KW series; The third is the variable frequency power type series EPS ----- YJP series that directly supplies power to the motor.
1.2 Design requirements for EPS emergency power supply: EPS emergency power supply is a new industry that developed rapidly in 2002, and its safety, reliability, applicability and rationality should be taken into account when designing EPS. It mainly includes: 1) The switching time of power failure is generally at the millisecond level (25ms) to ensure the timeliness of power supply; 2) Strong load adaptability, including capacitive, inductive and hybrid loads, and strong overload capacity and impact resistance; 3) Multiple outputs are available to prevent faults caused by single output; 4) There are fire linkage and remote control signals, which can be converted manually and automatically; 5) Strong environmental adaptability, suitable for various harsh environments, with measures to prevent high and low temperature, damp heat, salt fog, dust, vibration and rat bite; 6) Long service life, fast battery charging and management capability; 7) Energy saving, high operation efficiency and low operation cost; 8) There are unattended and automatic operation functions; 9) The startup emergency signal has complete functions, and can provide startup emergency signals under various abnormal conditions in time; 10) It has strong startup function to avoid failure to start after battery link protection; 11) No smoke, no noise, no pollution, etc; 12) Simple maintenance, low maintenance costs.
1.3 Design principle of EPS emergency power supply: 1) YJ's EPS emergency power supply is generally single-phase, mainly providing centralized power supply for emergency lighting occasions (shopping malls, entertainment places, office places, trading places, etc.). When the input power supply is normal, one of the mains power is output to the daily lighting through the conversion device, and the other is charged to the battery pack through the charger. When the controller detects mains power interruption or abnormality, it sends a start signal to the inverter and controls the mutual switching conversion device to switch to the inverter output. Of course, for different connection methods of EPS, EPS can also be used as a two-way power supply and a three-way power supply. 2) Emergency lighting and HY-YJS are generally suitable for occasions with complex load properties, so they are generally three-phase hybrid. The main application occasions are hotels, high-rise buildings, hospitals, banks, etc. 3) The frequency conversion power type EPS specially used for motors is mainly designed for motor loads to avoid equipment damage due to large current impact during motor starting. It is widely used in high-power motor loads, such as elevators, fire pumps, large fans, etc. The difference from other EPS is that this type of EPS generally has only one output. When the three-phase input mains power is normal, DC power is supplied to the inverter after rectification, and the battery pack is charged by the charger at the same time; When the three-phase input is powered off or abnormal, the battery pack will automatically supply DC power to the inverter. When the motor is required to work under load, send the starting signal (running signal, remote control signal) to the inverter, and the inverter will output immediately. Variable frequency from 0~50Hz is supplied to the motor for variable frequency starting. When the frequency reaches 50Hz, it will keep normal operation.
1.4 Current situation in the field of EPS emergency power supply: With the continuous development of science and technology, many intelligent buildings have sprung up. While people put forward higher requirements for their living environment, they also put forward the issues of power security and personal health and safety. However, EPS started later than generators and UPS, and people did not know enough about it. Therefore, in many emergency power supply occasions, generators and UPS are the main emergency power supply methods to realize the functions of EPS. In terms of providing emergency power supply capacity, these two methods have exposed many shortcomings.
2. Development trend of UPS/EPS
2.1 Control technology of UPS/EPS Most of the AC/DC and DC/AC converters of small and medium-sized UPS/EPS still use analog control circuits. Most of the control chips of AC/DC converters have been integrated, simple to use, and reliable to work. There are two basic control modes for DC/AC converter, one is single closed loop control, the other is double closed loop control. The former control circuit is simple, but it is difficult to realize automatic recovery of output short circuit. The latter control has an inner current loop and an outer voltage loop. The output of the voltage regulator is given by the current regulator. Therefore, limiting the given amplitude of the current also limits the larger output current of the inverter. At present, digital control has become the mainstream of the development of new UPS/EPS control technology. The digital controller has high precision, strong anti-interference ability, easy to realize the detection, fault diagnosis and isolation of UPS, easy to realize remote control and telemetry, realize the parallel connection and hot plug of multiple UPS, and easy to realize the monitoring and management of batteries. That is to say, the intervention of computers makes UPS intelligent and can make it run in a better state.
2.1.1 The application of DSP adopts digital PWM technology of digital signal processor (DSP), which is the core of digital control technology and is used to ensure the quality of UPS/EPS output voltage, that is, to ensure that the output voltage, frequency and output voltage waveform meet the requirements of technical indicators. Another important function of digital control is to realize the initial self-test and operational self-test of UPS/EPS, and perform fault protection and fault isolation, which is not competent for analog controllers. Because of the flexibility of the digital controller, the hardware circuit of the UPS controller can be standardized, which simplifies the production, use and maintenance, and greatly improves the working reliability.
2.1.2 The fully microprocessor based UPS/EPS circuit of the control circuit is composed of the following parts: main circuit, drive circuit, monitoring display and control protection circuit and communication interface circuit. The monitoring, display and control protection circuit and communication interface circuit can use digital design skills to simplify their circuits, and solve the shortcomings of the original analog circuit that needs adjustment, has temperature drift and is difficult to adjust parameters. The methods adopted are: 1) full microprocessor-based use of microprocessors to perform the functions of monitoring, display and control the protection circuit and communication interface circuit; 2) Semi microprocessor uses analog circuit to process fast feedback protection circuit, while processor processes slow feedback, start emergency signal, display and communication interface functions.
2.2 Battery technology The battery is the heart of UPS/EPS. No matter how advanced the UPS/EPS circuit is, its performance ultimately depends on its battery. Once the battery fails, no matter how good the UPS/EPS can provide uninterrupted power supply. At present, UPS/EPS generally uses maintenance free sealed lead-acid batteries. Due to the adoption of anion comparison absorption sealing technology, it overcomes the shortcomings of regular water supplement for ordinary batteries, and has the advantages of "maintenance free", convenient use, no environmental pollution, small size, and light weight. It uses grid materials with high hydrogen overpotential to reduce the gas decomposition of the battery during storage and charging. The superfine glass fiber membrane on the surface prevents the active substances from falling off and improves the battery life. The use of the safety valve makes the battery produce little gas, and the generated oxygen can be absorbed by the negative lead, so that the battery has no water loss, achieving the purpose of sealing and maintenance free. Generally, the main factor affecting the battery performance is continuous charging, which will reduce the service life of the battery by about half. At present, an ABM three-stage battery management scheme is used abroad, that is, charging is divided into three stages: the front stage is constant current balanced charging, charging the battery capacity to 90%; The second stage is floating charge, charging the battery capacity to 100%, and then stop charging; The third stage is natural discharge. In this stage, the battery uses its own leakage current to discharge until it reaches the specified lower voltage limit, and then repeat the above three stages. In this way, the battery is still in the floating charge state 24 hours a day after being fully charged, thus extending the battery life. The metallized Ni MH battery has the advantage of high energy density and no cadmium pollution caused by Ni Cd battery. Its application in UPS/EPS can receive the advantages of small size and lightweight. But the disadvantage is that the price is too high. The high-power lead air standby power unit (RPU) developed by Alupower Company in the United States has run for ≥ 50h, power ranges from 600W to 6000W, and voltage ranges from DC24V to 48V. Its energy density is more than ten times that of lead-acid batteries, its weight is only 1/10 of that of lead-acid batteries, and its space is only 1/7 of that of lead-acid batteries. It is expected to replace lead-acid batteries in UPS/EPS.
3. The development trend of EPS emergency power supply Due to the complexity of the load type carried by EPS and the relative fixity of the environment, the EPS function can be closer to the real application for different occasions and loads. These include the following aspects. 1) Structure composition In order to better combine practical applications, ordinary EPS often adopts the "multi in one" structure design. However, due to the complexity of load and environment, it also brings difficulties in equipment standardization and selection of design institutes and users. The solution is to use modular design to separate the host from the input or output power distribution. The host module completes the main energy conversion and communication control functions; The power distribution module realizes rich power distribution management functions. The host module manages the power distribution module through the standard control interface, such as the dual power automatic switching function, the multi circuit output function, and the fire linkage function should be realized in the power distribution module. 2) The power distribution module should add the function EPS for power supply of emergency loads, whose loads are often non single loads, and these loads have different criticality in emergency situations. Therefore, for EPS, some power distribution management functions are critical. (1) For example, a large part of the EPS load is inductive impact load, which has a large starting current. When selecting the model, the EPS capacity must be increased, which results in waste of equipment resources and increase of user costs. In fact, due to the interruptibility of EPS load power supply, EPS can add an 8-way or 16 way programmable power distribution management interface. By controlling the sequence and time of load startup, the problem of starting impulse current and increasing the selection capacity can be solved to a large extent. (2) The partial unloading function is determined by the nature of the EPS load. When an overload occurs, the EPS needs to continue to work as far as possible instead of performing a protective shutdown like the UPS. Therefore, the secondary load can also be removed through the power distribution management interface. 3) Battery management Since the service environment of EPS is generally worse than that of UPS, in order to maximize the service life of the battery, the charger should also have the following functions: (1) charging current limit can be set; (2) Battery discharge termination voltage can be set; (3) With automatic floating charge function, the charging mechanism shall comply with DIN41773 standard; (4) With floating charge voltage temperature compensation function; (5) Intelligent battery detection function; (6) Deep discharge protection (mandatory emergency). 4) Variable frequency starting function At present, the design of variable frequency starting EPS mainly focuses on solving the starting impact problem of large motors, such as elevators, water pumps, fans and other loads, but a more reasonable design should be the perfect combination of online UPS and inverter technology. Online UPS has mature rectifier and battery management technology; The inverter has mature frequency conversion control technology, and the combination of the two agricultural production systems is the final development direction of this application field.
With the progress and development of society and the continuous improvement of environmental requirements, people are paying more and more attention to fire awareness. EPS emergency power supply will be recognized and adopted by people because of its unique advantages. In a project, it can be flexibly applied to the end of fire power supply circuit, individual important occasions and other situations. The selection of emergency power supply is no longer limited to diesel generators, because their respective characteristics are applicable to different projects, which will provide a more powerful guarantee for the safety of the whole society.
