Our Hot Topic comes via an interview with PPI Power CEO Jim Haig during APEX in Anaheim and we thought it was so pertinent to our industry that it has become our feature for this week’s IFExpress.
You might remember that IFExpress is dedicated to IFEC companies big and small and that’s why we chose PPI Power. With only some 32 US employees, this company fits the “small” moniker but when you realize that without them almost all of the IFE we have come to know and love would not be permitted on today’s aircraft. PPI unitsconvert the aircraft 115Vac (400 Hz) power (and 28 VDC) to something that the logic circuits can use, isolated low voltage DC power. As you might guess, this is important, as the devices connected to the aircraft power systems cannot cause the current to be out of phase with the voltage – no lead or no lag. Unfortunately those big transformers and capacitors you see on most power supplies love to do just that, change the phase of the current relationship with the voltage and that is why Jim is so proud… when his power supplies are connected to the aircraft power, they just look like a simple, resistive load (no lead or lag of the current with respect to the voltage – this is called unity Power Factor). This is why you see the letters PFC (in their product names… but there will be more on this topic later.) We also note that by downloading the 81505 module data you will get a better description of the type of products and circuitry involved in making it work.
As an aerospace circuit design engineer, Jim began his career with the big names in the Defense Industry working on highly complex and reliable power supplies. Aerospace demands high quality power supplies for digital electronics that generate very low noise and look like resistive loads (remember unity Power Factor) and early in the nineties he was asked to help one big IFE company to get better performing power supplies for their IFE. He did so and his new company PPI Power was off to the races.
PPI Power found customers based on the fact that at the current specification level, their IFE hardware did not meet the new and demanding PFC requirements, generated too much “noise” or both. As you might expect, when the voltage and current are out of phase, bad stuff happens, namely extra power is consumed and generally the harmonic “noise” a system generates increases. This is especially bad at higher line frequencies such as 400–800Hz that modern aircraft power system run at, not to mention the system is at 35,000 feet above the ground where every extra Watt consumed is critical.
According to our sources, PPI products work extremely well and are amongst the most reliable in the industry. According to Jim, “PPI Power is going into our twenty first year of supplying to the IFE industry. We were the first company to develop a Power Factor Correction (PFC) solution specifically geared for IFE systems onboard commercial planes and because the power grid involves sign waves, harmonic distortion minimization will always be important. Our product goal is to correct the way the IFE system boxes draw power from the aircraft power busses; to preserve the integrity of the total power system. If many units on the power bus draw non-linear distorted input currents, the bus “rings” and the voltage can get really ugly! This can result in compromising peak detection circuits losing the ability to synchronize multiple generators; an important part of bringing generators back on line.”Readers, remember many of these aircraft power systems are multiple generator systems that have to have synchronized AC generators. Further, the system electronics have to be able to control real and apparent power (out of phase current and voltage).
It is interesting to note that while the US does not yet mandate Power Factor Correction on consumer electronics (most “GREEN” one’s do), Europe has required devices like PC’s and TV’s to do so. Interestingly, Power Factor Corrected electronics on the plane also use less power because there is less wasted in the wiring and distribution networks (less heat too) and that makes it a good thing for aircraft where fuel burn is critical and power is limited. But in general, PFC products are used where the current and voltage would otherwise be misaligned in supporting cabin hardware and thus line harmonics also are minimized almost to zero (and this isn’t easy) if they exist at all. We should also note that many Business Jets use 28 Volts DC for equipment power and thus don’t need PFC. However, we understand that today, some new, bigger BizJets do have AC. Furthermore, the power requirements really bloomed in the 90’s and today Boeing has their DO-160 requirements, while Airbus uses ABD 0100.1.8 for theirs. We understand that the new Airbus A350 is even more demanding. Mr. Haig noted that they do meet all the requirements for the Boeing B787 and are very close to meeting all of the A350’s.
Today, PPI Power has over 50 off-the-shelf standardized power supplies and modules aimed at the IFEC industry. Products focused on the above mentioned power solutions. Since PPI Power began, they have delivered over 135,000 units to date – a success story by any measurement. They provide supplies and modules to companies including Panasonic, Kontron, Telefonix, Viasat and many more. To give you an idea of a final product, we used a picture of a Power Factor corrected 200 watt supply for an aircraft electronics box that supplies DC power in the 3 to 5 volt range as today’s large rectangle image for this article.
You don’t have to be a rocket scientist to see the future of PPI Power products – one could expect tougher specifications for noise, higher efficiency, smaller size, and, of course, lower price. Jim told IFExpress that his whole company is always striving to improve their products and meet the ever growing spec requirements. He did point out that although no one can ever defeat physics, it certainly keeps us on our toes trying. He also noted that as the new AC frequencies go to 800Hz and beyond (cycles per second)…“The higher peaks will be difficult but not insurmountable!!”
View the original article here.