Abstract:
This is directed to systems, processes, machines, and other means that enable automatic shifting of current loads in a three phase power system. The invention can rapidly shift power phases to various loads such that each phase could power each load, resulting in equalizing the average current in each power phase.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Patent Application No. 61/500,533 filed Jun. 23, 2011. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not Applicable 
       THE NAMES OF PARTIES TO A JOINT RESEARCH AGREEMENT 
       [0003]    Not Applicable 
       INCORPORATION BY REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC 
       [0004]    Not Applicable 
       FIELD OF THE INVENTION 
       [0005]    This invention relates to utilizing three-phase power more efficiently by balancing the loads on each of the three phases. 
       BACKGROUND OF THE INVENTION 
       [0006]    The advantages of a balanced three-phase power system comprising balanced three-phase sources and a balanced three-phase load when compared to a single-phase system are well known. As Kumar explains in  Electric Circuits and Networks : first, power loss in a transmission system is lower in a three-phase system. Second, copper utilization is less in a three-phase system. Third, electrical components designed for three-phase operation are more efficient than their single-phase counterparts. However, when the loads are unbalanced, the three-phase system suffers from pulsation and substantial system inefficiency. 
         [0007]    Current solutions to this problem partially resolve the matter and are insufficient. As indicated below, other systems shift one-phase loads, try to mitigate the system pulsation, or adjust the neutral current. 
       BACKGROUND ART 
       [0008]    The Cheng U.S. Pat. App. No. 2010/0033154A1 teaches a power converter with a constant time control for use in single phase switching regulators. The current invention applies to power lines using three phase power and not pulse width modulators. 
         [0009]    The Carpenter U.S. Pat. No. 7,903,433 teaches a power converter that transfers some current load between power phases in a circuit. The current invention uses a series of relays to transfer power phases to different loads entirely, rather than partially. 
         [0010]    The Kim U.S. Pat. No. 7,732,940 teaches load switching as a means for reducing neutral current in a three phase circuit. However, it does not teach a method for rotating power phases to loads in a three phase power system. 
       BRIEF SUMMARY OF THE INVENTION 
       [0011]    Methods, systems, and other means are provided for balancing the loads on each phase of a three-phase power system. In accordance with some embodiments, 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0012]    Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein: 
           [0013]      FIG. 1  is an explanatory illustration of the first portion of the circuit layout. 
           [0014]      FIG. 2  is an explanatory illustration of the second portion of the circuit layout. 
           [0015]      FIG. 3  is an explanatory illustration of the third portion of the circuit layout. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0016]    Embodiments of the present invention overcome many of the obstacles associated with electrical system with a three phase power source and a three phase load, and now will be described more fully hereinafter with reference to the accompanying drawings that show some, but not all embodiments of the claimed inventions. Indeed, the machine may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like reference characters refer to like elements throughout. 
         [0017]      FIG. 1  shows the timing portion of equalization circuit  10 . Phase U is electrically coupled to a neutral through a zero-cross detector. The zero-cross detector comprises Diode D 4 , Opto isolater U 4  and Insulated Gate Bipolar Transistor (“IGBT”) Q 4  and zener diode Z 1 . Opto isolater U 4  is an electronic device designed to transfer electrical signals by utilizing light waves to provide coupling with electrical isolation between its input and output. Opto isolator U 4  prevents high voltages or rapidly changing voltages on one side of the circuit from damaging components or distorting transmissions on the other side. 
         [0018]    One shot U 5  creates an initial pulse at startup which resets Johnson counter U 6  to Zero. After the device is in operation, phase U travels through the zero-cross detector. One shot U 10  shapes the pulse width which then travels to one shot U 7 . One shot U 7  reshapes the pulse width which then travels to Johnson Counter U 6 . Johnson Counter U 6  creates first enabling output A, second enabling output B and third enabling output C in a cycle based on the setting of the timer in Johnson Counter U 6 . In this embodiment, Johnson Counter U 6  is a timing mechanism. 
         [0019]    Johnson counter U 6  is electrically coupled to quad-NOR logic device U 8 . Quad-NOR logic device U 8  resets Johnson counter U 6  to zero at an interval determined by a user setting and at startup from one shot U 5  as explained above. When zero cross detector Z 1  detects zero phase voltage zero cross detector Z 1  emits an electronic pulse to Johnson counter U 6  as the AC voltage goes through zero volts. Johnson counter U 6  counts the number of AC voltage cycles and provides one of: first enabling output A, second enabling output B or third enabling output C every ‘n’ cycles. Here, ‘n’ is a setting chosen by the user by calibrating Johnson counter U 6  and quad-NOR logic device U 8 . Here, ‘n’ can be any number of cycles greater than or equal to 3, for instance to balance every second, ‘n’ would be 20. 
         [0020]    Hex inverter U 9  is a logic device that takes either first enabling output A, second enabling output B or third enabling output C and inverts each output from Johnson counter U 6 . After being inverted by hex inverter U 9 , first enabling output A, second enabling output B or third enabling output C travels to a bank of switches as shown in  FIG. 2 . 
         [0021]      FIG. 2  shows a plurality of one shot multivibrators in equalization circuit  10  which form a switching mechanism. First enabling output A activates one shot multivibrator U 1 , which travels through transistor Q 1  which amplifies first enabling output A to create to first enabling output D. Second enabling output B activates one shot multivibrator U 2 , which travels through transistor Q 2  which amplifies second enabling output B to create second enabling output E. Third enabling output C activates one shot multivibrator U 3 , which travels through transistor Q 3  which amplifies third enabling output C to create third enabling output F. One shot multivibrator U 1 , one shot multivibrator U 2  and one shot multivibrator U 3  provide pulsewidth for relay S 1 A, relay S 1 B, relay S 1 C, relay S 2 A, relay S 2 B, relay S 2 C, relay S 3 A, relay S 3 B, and relay S 3 B (collectively, “the relays”) as shown in  FIG. 3 . The proper pulsewidth for one shot multivibrator U 1 , one shot multivibrator U 2  and one shot multivibrator U 3  is that which is necessary to drive the relays. 
         [0022]      FIG. 3  shows the connections between the various phases and loads. There are three power phase inputs from a power source: a first power phase—power phase U, a second power phase—power phase V and a third power phase—power phase W. Similarly, there are three loads: a first phase load—load U, a second phase load—load V and a third phase load—load W. First enabling output D is electrically coupled to a first bank of switches: first, from power phase U to relay S 1 A and then to load U, second from power phase V to relay S 1 B and then to load V and third from power phase W to relay S 1 C and then to load W. Second enabling output E is electrically coupled to a second bank of switches: first, from power phase U to relay S 2 A and then to load V, second from power phase V to relay S 2 B and then to load W and third from power phase W to relay S 2 C and then to load U. Third enabling output F is electrically coupled to a third bank of switches: first, from power phase U to relay S 3 A and then to load W, second from power phase V to relay S 3 B and then to load U and third from power phase W to relay S 3 C and then to load V. 
         [0023]    The first bank of switches, the second bank of switches and the third bank of switches, may sequentially activate in response to the enabling output from Johnson counter U 6  with each one on only one-third of the time. In this manner, power phase U, power phase V and power phase W are rotated among load U, load V and load W. 
         [0024]    In some embodiments, during a first cycle, the first bank of switches connects power phase U to load U, power phase V to load V, and power phase W to load W. During a second cycle, the second bank of switches may connect power phase V to load W, power phase W to load U, and power phase U to load V. During a third cycle, Johnson counter U 6  may rotate the phases so that the third bank of switches may connect power phase W to load V, power phase U to load W, and power phase V to load U. The cycle may start over and the phases are again rotated to the three loads, thus equalizing the current load of load U, load V and load W among the three incoming power phases U, power phase V, and power phase W during each cycle. 
         [0025]    By modifying Johnson counter U 6 , power phase U, power phase V, and power phase W may be rotated every ‘n’ cycles, where ‘n’ can be a number from 3 to as high as is practical from a power standpoint. For example, if ‘n’ is 20, the phases will rotate every 3*n=60 cycles, or every second in a 60 hertz power system. If ‘n’ is 400, the 3 phases will rotate every 1200 cycles, or every minute, etc. Every third time the phases are rotated, the average current is equalized among power phases U, power phase V, and power phase W. 
         [0026]    In one embodiment, the relays may be solid-state relays (SSR&#39;s) if the current is relatively low. As used here, a relatively low current is about 100 amperes or less. In this embodiment, relay S 1 A is a first solid state relay, relay S 1 B is a second solid state relay, relay S 1 C is a third solid state relay, relay S 2 A is a fourth solid state relay, relay S 2 B is a fifth solid state relay, relay S 2 C is a sixth solid state relay, relay S 3 A is a seventh solid state relay, relay S 3 B is an eighth solid state relay, and relay S 3 B is a ninth solid state relay. 
         [0027]    In another embodiment the relays may be silicon-controlled rectifiers (SCR&#39;s) if the current is moderate. As used here, a moderate current is in the hundreds of amperes. In this embodiment, relay S 1 A is a first silicon-controlled rectifier, relay S 1 B is a second silicon-controlled rectifier, relay S 1 C is a third silicon-controlled rectifier, relay S 2 A is a fourth silicon-controlled rectifier, relay S 2 B is a fifth silicon-controlled rectifier, relay S 2 C is a sixth silicon-controlled rectifier, relay S 3 A is a seventh silicon-controlled rectifier, relay S 3 B is an eighth silicon-controlled rectifier, and relay S 3 B is a ninth silicon-controlled rectifier. 
         [0028]    In a third embodiment, the relays may be insulated gate bipolar transistors (IGBT&#39;s) if the current is relatively high. As used here, a high current is in the thousands of amperes and volts. Of course, IGBT&#39;s are extremely versatile and can be used at any level of current and voltage. In this embodiment, relay S 1 A is a first insulated gate bipolar transistor, relay S 1 B is a second insulated gate bipolar transistor, relay S 1 C is a third insulated gate bipolar transistor, relay S 2 A is a fourth insulated gate bipolar transistor, relay S 2 B is a fifth insulated gate bipolar transistor, relay S 2 C is a sixth insulated gate bipolar transistor, relay S 3 A is a seventh insulated gate bipolar transistor, relay S 3 B is an eighth insulated gate bipolar transistor, and relay S 3 B is a ninth insulated gate bipolar transistor. 
         [0029]    Unlike the SSR&#39;s, the SCR&#39;s and IGBT&#39;s may need a separate ‘firing’ card to turn them on and off. The nine switches may be connected three at a time to the three electrical phase wires from the power source and to the load. A different bank may be connected to the load every cycle or every ‘n’ cycles. 
         [0030]    These three embodiments can be used in a variety of settings. The first setting is for end electricity users, such as an individual home or business. Individuals can reduce the electrical load one&#39;s home or business uses by more efficiently using the power provider. This provides two primary advantages: first, less electricity is consumed resulting in a smaller electricity bill; second, appliances do not suffer from phase vibration, as explained above resulting in longer lives for consumer and business electronics. 
         [0031]    The second setting is for groups of end-users such as those receiving electrical power coming from a transformer or electrical power sub-station. In this case, the end users frequently receive different combinations of two phases of power and the distribution method is frequently more random than efficient. Having the disclosed invention in a transformer or electrical power sub-station avoids the power loss in inefficient random distribution of phases. 
         [0032]    The third setting is for one for electrical power generators. In this case, the electrical power generator can produce less electricity; yet power the same number of consumers with the same needs by simply using the energy more efficiently. This applies to those using standard electrical generators and not motor-generators, since motor generators do not have load-balancing concerns.