Discussion on Special AC Stabilized Power Supply
Social progress and technology continue to develop, and users also require AC regulated power supplies to have voltage stabilization functions, anti-interference and harmonic suppression functions for the normal use of their own equipment. In order to meet market demand, the company has recently launched various special power supplies, such as CT machines. , Special regulated power supply for NMR-CT machine, anti-interference AC parameter regulated power supply, regulated filter power supply, voltage regulation and regulated power supply, etc.
1. Anti-interference AC parameter regulated power supply
AC parameter regulated power supply is also called Constant Voltage Transformer (CVT) for short. Its basic principle is to use the principle of ferromagnetic resonance to make a functional converter. A special structure iron core is equipped with a linear inductance coil, a saturated inductance coil and a compensation Inductance coils realize their respective functions. The primary core will use the linear segment of the core magnetization curve, while the secondary core will use the shallow saturation region of the magnetic properties. When the input voltage rises again, its magnetic field does not affect the saturated iron core, so as to achieve the purpose of voltage stabilization. This kind of power supply has a unique and simple structure, is stable, reliable and safe, and has a wide range of voltage regulation. When the input voltage changes by ± 20%, the output voltage changes by ± 3%, the overload protection ability is strong; when the load is short-circuited, the output voltage will automatically drop to ensure the safety of the equipment, the input and output are completely isolated, there is no direct connection of electricity, there is shielding and absorption It has good two-way suppression and attenuation effect on pulsed interference signals from hundreds of Hz to tens of thousands of Hz, and the common mode suppression is ≥ 50dB. In addition, one of the very important features is that the effect of suppressing the harmonics of the power grid is obvious, the voltage waveform is significantly improved, the third harmonic reduction rate reaches more than 90%, and the odd and even harmonics such as 5, 6, 7, 8, and 11 All have obvious improvements, especially suitable for supporting power supplies of various instruments and equipment in lines with serious harmonic pollution, and can also be used for control system power transformers in precision equipment.
The level of technology and workmanship has been improved, and the noise level of the whole machine has been greatly reduced. The CVT is too noisy and affects the use, so it can be used with confidence at present.
2. A new type of AC power supply that stabilizes voltage and suppresses harmonics
At present, the harmonic suppression of the power grid has become a very important task for the power supply department. With the development of power electronics technology in recent years, active power filtering has become the most promising filtering method to solve the voltage distortion of the power grid. Using the series active power filter method, a new type of power supply has been developed to stabilize voltage and suppress harmonics, which is called series power quality controller (SPQC: Serial Power Quality Controller), which is similar to the voltage dynamic restorer abroad. This product can not only stabilize the voltage but also suppress the harmonics of the power grid, and it can also be called a voltage stabilization filter. This kind of voltage stabilizer can also dynamically compensate the three-phase unbalanced voltage flicker, drop, surge, peak, etc., the mains voltage is unstable, and has harmonic pollution. After the instantaneous dynamic voltage compensation of the instrument, Pure three-phase sinusoidal balanced voltage on the load.
A three-phase voltage stabilizer filter with a load capacity of 15kVA, when the input voltage is 170 ~ 210V, the total voltage harmonic distortion rate is 8.8%, with an inductive motor and switching power supply load, the output voltage is between 219 ~ 224, the voltage The total harmonic distortion rate drops to 2.8%, while the output waveform is significantly improved.
It is undoubtedly the best choice for petroleum exploration precision instruments, power supplies for signal lights at stations along electrified railways, and line precision instruments in areas with poor power grid quality.
3. Medical special power supply
Medical system CT machines have been widely used in various hospitals. If the power supply is not configured properly, the resolution of the CT film will be poor, which will bring difficulties to the doctor's diagnosis, and may also miss the patient's condition. The characteristics of the power supply used by the CT machine itself: 1. When exposing the lesions, the output current of the stabilized power supply is required to be large and the voltage drop is small, and no adjustment is made at this moment; 2. The CT itself has a rectifier circuit that generates harmonics, which affects the action control of the stabilized power supply. Incorrect, more than ten years of experience in supporting power supplies for GE-CT, reducing internal resistance in regulated power supplies, adding harmonic filtering devices to the output, adding locking functions and surge absorbing circuits to the control circuit, etc., taking a series of measures to design Medical dedicated power supply to meet user needs.
4. AC voltage regulating and stabilizing power supply
In recent years, the market demand has gradually increased, and most of them require relatively large capacity. This kind of product that integrates voltage regulation and voltage stabilization functions is called "voltage regulation and stabilization power supply" or adjustable and stable voltage regulator. Products include inductive, power electronics and transformer types of voltage regulating and voltage stabilizing power supplies. Each type has its own characteristics and shortcomings, which will not be described here. A closed-loop column-type voltage-regulating regulator is composed of a multi-stage voltage regulator and a column-type compensation AC voltage stabilizer, which regulates voltage while maintaining a stable output voltage. This kind of voltage regulating regulator has developed rapidly in recent years, with a capacity range of 30kVA ~ 200kVA. Compared with the inductive type, it does not have fixed rotation and air gap, has no-load current and no-load loss, and the waveform is not distorted (waveform distortion Accuracy <0.5%), fast voltage regulation speed, strong instantaneous overload capacity, has been widely used.
The load capacity continues to increase, and the demand for high-voltage and large-capacity voltage-regulated and stabilized power supplies has been proposed from time to time. Some users have proposed a column-type voltage regulator with a demand of 1000kVA to 3000kVA. Society and user requirements are the driving force for technological development. The production unit is user-oriented and develops Multi-functional, large-capacity voltage-regulated and regulated AC power supply meets social needs. Safety cannot shirk responsibility.
