Technical 2017-04-22T07:58:17+00:00

Technical Diagram of How the BPU™ Functions


The BPU™ provides the only known comprehensive solution addressing the problematic areas in Power Quality. To achieve similar the performance as that provided by the BPU™ would require many different devices integrated properly making the BPU™ cost and space competitive. As it relates to how the BPU™ achieves these results, the following is a flow chart of the internal network.

High Level Block Diagram of the BPU™


The Iterative control transformer modules (Ref 4) represent the inductor.  This inductor is connected to Storage 1, which is an Active Filter Network (S1).

This provides for surge suppression as well as harmonic filtration.  The Iterative transformer is also able to capture lost energy and store it for future use.  The Iterative control transformer and Storage 1 provide for a voltage drop to Storage 2, which is with Notch Filters.

Although Storage 2 acts as an EMI filter, it is primarily a notch filter stage setup for blocking out spikes with the harmonic section.

The last stage (Stage 3) is designed for power factor correction, working in conjunction with the other stages.  The voltage drop from the Iterative Control Transformer, in parallel with Storage 1, reduces the size and number of capacitors required for power factor correction for the whole facility.  It also eliminates harmonics and transients that could adversely affect the larger capacitor bank (Storage 2).

The Iterative Control Transformer also acts as a clamp during inrush conditions.  For example, if the main breaker is turned off and suddenly is turned on, all the loads in the facility would be activated.  The BPU™ will clip the peak current inrush demanded by the loads by releasing the power saved by the charged capacitors in the Stage 3 locations.

Reference #1 – EMI Phase Filter – Front End on Load Side


(BPU) compact 3 phase section filters are active for use with switch mode loads of all types.Phase filters provide stand-alone or enhancement level performance for FCC and CISPR/EN requirements in a Deltaor Wye system, they detect on load requirements needed. The low leakage 3 phases is active with the “B” circuit to increase common mode performance in a location.

The vast majority of these problems originate with random electrical noise and stray signals from other equipment, or other outside line sources. The resulting system malfunctions can include:

  • Failure to respond to signals on first command
  • Mysterious turn on and off of controlled devices from older motors creating a very fast inrush
  • Unexplained 50-ohm restive characteristic of a very low impedance on the mains
  • In addition to the absolute impedance level encountered, a reactive component further complicates the selection process on the line to line.

The “(BPU)” RFI section corrects these problems and maintains the filtering for a clean AC line in it’s location working with many devices as variable speed drives systems in a location are introduced to the reference #1 filter, were as the transformer blocks the full load of the capacitance on the mains until needed.

  1. 00
  2. Delta

Reference #2 – Surge Suppression – Front End on Load Side


The Surge Suppression section maintains a protective device focus on limiting high-voltage spikes to a level that is acceptable to most electronic equipment and control devices in a building. Plus, they’re serve as clamping mechanisms for high-energy impulses in the “BPU” keeping the currents in the capacitors to a minimum amount for long life. They also work with the C-L-C circuit on the front end of the “BPU” and the mains that are connected to in clapping the line voltages to the building.

 Reference #3 – Harmonic/Snubber Filter – Front End on Load Side


Inside the Harmonic Filter

The harmonic filter is built using an array of capacitors, inductors, and resistors that deflect harmonic currents to the ground system in the ‘ (BPU)”. Each harmonic filter could contain many such elements, each of which is used to deflect harmonics of a specific frequency. A harmonic filter is used to eliminate the harmonic distortion caused by equipment. Harmonics are currents and voltages that are continuous multiples of the fundamental frequency of 60 Hz such as 120 Hz (2nd harmonic) and 300 Hz (5th harmonic). Harmonic currents provide power that cannot be used and also takes up electrical system capacity. Large quantities of harmonics can lead to malfunctioning of the system that results in downtime and increase in operating costs. The second harmonic would have a frequency of 120 Hz; the third harmonic would have a frequency of 180 Hz and so on. The “(BPU)” active harmonic filter is something like a boost regulator. The concept used in an active filter is the introduction of current components using power electronics to remove the harmonic distortions produced by the non-linear load. Active harmonic filters are mostly used for low-voltage networks with a hybrid filter and with a combination of an active and a passive filter together is installed on the load side of the “(BPU)” in a parallel configuration. This active harmonic filter will respond from the 1st odd harmonic to as high as 3000 th harmonic on the system main lines sending it to the ground system.

Inside the Snubber Filter

The “ (BPU)” Snubber filter absorbs the “Noise” caused by large inductive loads, such as power equipment switching on and off. The Snubber helps assure your controls operate properly and extends the life of relays and power contactors. A low-loss snubber network helps to reduce the motor terminal surge voltages from the line to line spikes within the capacitors front end. The snubber consists of the series connection of charging/discharging capacitor and the voltage-clamped capacitors.

Reference #4 – Transformer – “Iterative Control Transformer”


The Iterative Control Transformer modules (Number 2) represent the inductor in Figure 4. This inductor is connected to Storage 1, which is a small capacitor bank . This provides for surge suppression as well as harmonic filtration. The Iterative transformer is also able to capture lost energy and store it for future use. The Iterative control transformer and Storage 1 provides for a voltage drop to Storage 2, which is a larger bank of capacitors (Storage 2). Although Storage 2 acts as a notch filter, it is primarily a notch filter stage setup for blocking out spikes with the harmonic section.

The last stage (Ref:6 ) is designed for power factor correction, working in conjunction with the other stages. The voltage drop from the Iterative Control Transformer, in parallel with Storage 1, reduces the size and number of capacitors required for power factor correction for the whole facility. It also eliminates harmonics and transients that could adversely affect the larger capacitor bank (Ref:8 ).

The Iterative Control Transformer also acts as a clamp during inrush conditions. For example, if the main breaker is turned off and suddenly is turned on, all the loads in the facility would be activated. The (BPU) will clip the peak current inrush demanded by the loads by releasing the power saved by the charged capacitors in the Ref:9 in the Snubber Network filter location.

Ground System

Reference #5 – Storage 1/Active Filter Network


Since the “ (BPU)” storage 1 is a product of quadratic terms, the transfer function represents a series of cascaded second-order low-pass stages, with a, and b, being positive real coefficients. These coefficients define the complex pole locations for each second-order filter stage, thus determining the behavior of its transfer saturation function of the transformer as a L – C circuit with storage from the capacitors. The following types of predetermined filter coefficients are listed in the “ (BPU)” stages. The Butterworth coefficients, optimizing the pass-band filter for maxi- mum flatness in frequencities with spikes and noise across the transformer. The transfer function of a passive RC filter does not allow further optimization, due to the lack of complex poles of the transformer. The only    possibility to produce conjugate complex poles using passive components is the application of LRC filters incorbrated in the “ (BPU)”. However, these filters are mainly used at high frequencies removal of noise on the capacitors. In the lower frequency range (< 10 MHz) the inductor / capacitor values become very large in the unit for removal of any unwanted noise on the transformer and the snubber network at this point.

Reference #6 – Phases and Currents


The “ (BPU) detects unbalanced voltages in terms of value and phase position. Such unsymmetric conditions can occur due to break of a conductor, blown fuses or unbalanced loading of the three phases system. These conditions always result in displacement of the star point. The negative sequence voltage is measured by the “ (BPU)” transformer in the circuit. Senceing principle: A rotating three-phase system can be split according to the method of “Symmetrical Components“ into a positive-sequence system, a negative-sequence system and a zero sequence system. The “ (BPU)” calculates the negative-sequence system by rotating the voltage vector U2 by 240° and the voltage vector U3 by 120° and following addition of the voltage vectors.

Line-to-neutral Voltages Positive-sequence Phase Currents     Negative-sequence Phase Currents Total Phase Currents

 

 

 

The magnitude of each voltage is proportional to the length of the arrow or vector and the relative phase angle of each voltage is proportional to the angle between any two arrows. In the case above, the three voltages could have phase angles of zero degrees, 122 degrees, and 238 degrees. The phase-to-phase voltages would be 209.9, 200.1 and 209.9 volts. This would give an average of 206.7 volts, a maximum deviation of 6.5 volts and an unbalance of 3.15 percent. This shows the need to measure the voltages from phase-to-phase.

Reference #7 – Harmonic/EMI Filters


The Iterative control transformer modules (Number 2) represent the inductor in Figure 1. This inductor is connected to Storage 1, which is a small capacitor bank (C1). This provides for surge suppression as well as harmonic filtration. The Iterative transformer is also able to capture lost energy and store it for future use. The Iterative control transformer and Storage 1 provides for a voltage drop to Storage 2, which is a larger bank of capacitors (C2). Although Storage 2 acts as an EMI filter, it is primarily a notch filter stage setup for blocking out spikes with the harmonic section.

The last stage (Stage 3) is designed for power factor correction, working in conjunction with the other stages. The voltage drop from the Iterative Control Transformer, in parallel with Storage 1, reduces the size and number of capacitors required for power factor correction for the whole facility. It also eliminates harmonics and transients that could adversely affect the larger capacitor bank (Storage 2). The Iterative Control Transformer also acts as a clamp during inrush conditions. For example, if the main breaker is turned off and suddenly is turned on, all the loads in the facility would be activated. The BASIC POWER UNIT (BPU) will clip the peak current inrush demanded by the loads by releasing the power saved by the charged capacitors in the Stage 3 locations.

References #9 and 10 filter and condition the power for the large capacitor bank on the back end if the unit. The operating principles are the same as explained for References #1, 2 and 3 above. Reference #8 is explained within the text for Reference #4.