How to achieve high power density of industrial supplies - industrial supplies - electronics industry

How to achieve high power density of industrial supplies - industrial supplies - electronics industry

, High power density (to reduce space requirements), high reliability and high durability, as well as other less common in the general power of features such as easy-to-parallel, remote control and some of the overload protection function. Meanwhile, EMI and stability of its requirements more stringent than other applications. This paper analyzes a 400W power supply design example illustrates the primary side and secondary side power module used, and other ways to improve performance. In addition to

Electric Improvements, the module also uses a single form factor, easy to achieve precise and compact machine design and reduce the cost of installation and logistics. In fact, the two modules can have different power ratings, which greatly reduces time to market.

Level power factor correction (PFC), coupled with the bus or the DC link

Capacitance , Optimized for many different factors can not alone is very critical. Now, most power supplies are used in active PFC circuit, which boost converter, to ensure that the input current in phase with the input voltage to the input sine wave distortion minimized, thereby reducing the conduction EMI, to achieve wide input range (85VAC ~ 265VAC). Moreover, the boost converter input voltage regulation based on their duty cycle and input current, and the bus capacitor voltage regulator to 350V ~ 400V. However, if the boost converter is not active (for example in the start state), current may be flowing through the input rectifier, into the boost inductor and diode, to empty the bus capacitance, ultimately have a huge surge current. To avoid this problem, limiting the need for additional circuitry, or it may trigger a power fuse. In high-reliability or mission critical applications, due to the hold time and power protection requirements more stringent, so the bus capacitance must be increased, which makes the inrush current becomes larger. In some cases, the need for a NTC resistor, but in the "hot" start (such as power failure) time, NTC is still hot, can not provide protection. According to DIN-EN61204 standards, testing methods for two situations: 70% of the rated input voltage, 20ms; and 40% of the rated input voltage, 100mS. The second situation is not active PFC power supply run can be quite difficult.

Level pulse width modulation (PWM) converter is the main class. Which DC voltage is chopped to a higher frequency square wave, thus using smaller

Transformer Can be converted to another voltage level and provide isolation. Not all changes in topology are used duty cycle square wave, and some topology is used in frequency, while there is a change in phase between the two pulse sequences. This is a key to determine the converter efficiency and load regulation. Converter efficiency is important, first of all it is the power relationship between the cost of operation; secondly they must be cooled by the chassis to dissipate the heat generated; third thermal component, the more expensive, the greater space. These three factors and the cost of the power of life at stake.

Figure 1, the different level of industrial power and the main characteristics of each level

Converter topology of choice for efficiency and EMI radiation is critical, because power

Switch More inclined to hard switching, resulting in the dI / dt and dV / dt on the very same time, the higher current and voltage, which causes a large number of switching frequency harmonics generated. In various topologies, the resonant or quasi-resonant topologies have an advantage, but difficult to design, especially resonant topology, it is difficult to achieve wide load range. LLC topology described below, a wide load range with a limited switching frequency and soft switching, it is easy to solve this problem.

PWM level is all the core functions must be protected. In the current mode converter case-by-cycle current limit devices to protect against most of the power output of the injury problems, these problems are usually related with thermal shutdown.

Level synchronous rectification (SR) to generate the AC voltage transformer converted back to DC voltage. As the voltage is low, current is often quite high, so the rectifier conduction losses must be minimized. The use of a silicon PN junction diode forward voltage 0.7V available, then use

Schottky diode Up to 0.4V. To obtain a lower voltage level on the need to use MOSFET, then voltage level from the on-resistance RDS (ON) and output current decision, and the previous two cases is much lower. However, as MOSFET is the active devices, they need a proper gate drive signals to complete, if well designed, this level of power consumption can be greatly reduced, thus further improving efficiency. In addition, the use of advanced low-inductance packaging technology, design can be very compact and durable.

Continuous conduction mode (CCM) power factor correction

Input rectifier (Figure 2, there is no EMI

Filter ) Generated by the input voltage is fed into the PFC inductor, the time which the secondary coil for the PFC control

IC Provide power supply voltage. Inductor in front of resistance / capacitance network to the input voltage is sampled. Inductor followed with a gate protection circuit for power switch, PFC rectifier diodes for the StealthTM. Next, using a resistor divider to sense and regulate the output voltage of PFC stage, the feedback loop to this end. Bus capacitance is also shown in Figure 2, the diode D1 is an additional protection device.

Figure 2 PFC-level schematic diagram of

Controller used here is FAN4810, the device includes an advanced average current, "boost" type power factor correction circuit implementation, the power so to fully meet the IEC1000-3-2 specifications. It also includes TriFaultDetect features help to ensure that any single component failure in the PFC caused by unsafe event. 1A of the gate driver in turn greatly reduces the external drive circuitry. In addition, its low power requirements, not only improves the efficiency of lower component costs. The PFC also with a peak current limit, input voltage interruption protection, there is a over-voltage comparator can be reduced in the event of sudden load off PFC part of the event. Clock output signal used to synchronize the PWM stage downstream, in order to reduce system noise.

POST COMMENT

8 Ghoulishly Good Safety Tips for Halloween Quarry Safety—What You Need To Know Grilling Safety Measures Ensuring Spa Safety - Spa Steps, Spa Covers and More! Where to Get Electronics Direct broadcast satellite era is approaching, let us look forward to - direct broadcast satellite, satellite television, radio and television - Get A Bigger Penis Safety - The Natural Technique For Adding Inches Introduced Making The Most Out Of Aging Electronic Gadgets Programmable Electronic Banners Are Good For Business Oscilloscope Probes Does Vimax Work In Terms Of Safety? It's Time to Consider Palladium for Electronics Plating -- Again All you Need to Know about the OSHA 10 Hour Safety Course