Method of improving power density of high frequency DC power supply
Publisher: Administrator Date：2021-03-05
The technical indicators of high frequency DC power supplies can generally be divided into two types: one is characteristic indicators, including allowable input voltage, output voltage, output current and output voltage adjustment range, etc.; the other is quality indicators, which are used to measure output DC voltage. The degree of stability includes voltage regulation coefficient (or voltage regulation rate), output resistance (or current regulation rate), ripple voltage (surrounding and random drift) and temperature coefficient.
(1) Ripple voltage: AC voltage component superimposed on the output voltage. The peak-to-peak value observed by an oscilloscope is generally in the order of millivolts. An AC millivoltmeter can also be used to measure its effective value, but because the ripple is not a sine wave, there is a certain error. Generally, the ripple voltage of the high-frequency DC power supply is VP-P≤10mV.
(2) Voltage stabilization coefficient: Under the condition that the load current and ambient temperature remain unchanged, the relative change of the input voltage causes the relative change of the output voltage.
(3) Voltage adjustment rate: the relative change of output voltage when the relative change of input voltage is ±10%. Both the voltage regulation coefficient and the voltage adjustment rate indicate the influence of the input voltage change on the output voltage, so only one of them needs to be tested. .
High frequency DC power supply
Increasing the power density of high-frequency DC power supplies, making them smaller and lighter, is a common policy sought by manufacturers and customers. The high frequency of power supply is one of the hot research topics in the power electronics industry in the world. Miniaturization and weight reduction of power supplies are particularly important for portable electronic devices (such as mobile phones, digital cameras, etc.). The specific methods to miniaturize the high-frequency DC power supply are:
One is high frequency. In order to achieve high power density of the power supply, it is necessary to increase the operating frequency of the PWM converter and then reduce the volume component of the energy storage element in the circuit.
The second is to use piezoelectric transformers, which can make high-frequency power converters light, small, thin and high power density. Piezoelectric transformers use the characteristics of voltage-oscillation and "oscillation-voltage" that are unique to piezoelectric ceramic materials to transmit energy. Its equivalent circuit is like a series-parallel resonance circuit, and one of the hottest research topics in the field of power conversion.
The third is to select new capacitors. In order to reduce the volume and weight of power electronic equipment, it is necessary to try to improve the function of the capacitor, increase the energy density, and discuss the development of new capacitors suitable for power electronics and power supply systems. The demand for large capacitance, etc. The effective series resistance ESR is small, and the volume is small.
Shenzhen Sanxinda power supply equipment is a professional power supply manufacturer that produces electroplating power supply, electrolysis power supply, oxidation power supply, electrophoresis power supply and surface treatment power supply. The company adheres to the business philosophy of quality-oriented, energy-saving, and environmental protection, and strives to provide users with high-performance, high-efficiency, and high-reliability surface treatment power equipment.
SXD-PWH series high frequency switching power supply is a high frequency switching power supply originally developed and successfully developed by our factory. It has a completely different working principle from the previous power frequency silicon controlled rectifiers. It generates low voltage and large current output through the input high voltage AC rectifier-high voltage filter-high voltage and high frequency regulation-low voltage and high frequency rectification. Its working principle determines that the power supply has higher conversion efficiency and higher current conversion efficiency than the silicon controlled rectifier. Power factor has become the preferred power supply product for many customers. Using this power supply can significantly reduce production costs and improve product quality. Compared with thyristor power supplies, production energy consumption can be reduced by 20%-30%, bringing considerable economic benefits to users . The power supply is small in size and light in weight (water-cooled is smaller than air-cooled), and it is very easy to install and use, which can save valuable production space for users. The main power high frequency transformer of SXD-PWH series high frequency switching power supply adopts imported nano crystal/ultramicro crystal, high permeability material as the magnetic core, which is small in size and high in efficiency.
High-frequency and high-power switching components (IGBT), power drive modules, and three-phase bridge stack are all selected from international famous brands such as Mitsubishi, Fuji, Freetech, Germany, etc. The circuit board components are all selected from famous manufacturers. Our company has developed a unique water-cooled high-frequency electroplating power supply (patent pending), which has better cooling effect, anti-salt spray acidification, increases the service life of the power supply in harsh environments, and has stronger corrosion resistance, which can greatly extend the service life of the power supply. The water discharged from the machine is free of any pollution and can be recycled and reused!
SXD-PWH series high frequency switching power supply has complete protection functions: input phase loss, undervoltage, overheating, overcurrent, short circuit protection, safe and reliable.
The SXD-SS-SR series high frequency switching power supply has the following advantages compared with the ordinary switching power supply in the same market:
1. The full-bridge phase-shift soft switching control method is adopted to eliminate the switching stress to the greatest extent, and the world's latest full-bridge soft switching control IC is adopted, which has the function of automatically adjusting and setting the trigger pulse sequence parameters to achieve the best IGBT switching time. The IGBT switching loss is minimized, and the IC with its own synchronous rectification drive function is adopted, which simplifies the synchronous rectification drive circuit. Make its work more stable and reliable.
2. Adopt advanced logic interlock control circuit to eliminate pulse false trigger and overcome bridge arm short circuit.
3. It eliminates the magnetic bias problem, mainly in the following two aspects:
(1) The primary transformer of the main transformer uses series blocking capacitors
(2) Add an automatic bias correction circuit
4. Using foreign original imported MOS tube as the secondary side rectifier device, and using advanced and reliable special imported synchronous rectifier module technology, the efficiency of this high-frequency switching power supply is about 15% higher than that of similar ordinary rectifying switching power supplies under low-voltage and high-current conditions.