Abstract:
An on-line UPS has radio frequency filter, rectifier filter, battery, detecting circuit, controlling circuit and trigger circuit, and its efficiency approximate a hundred percent. No matter what commercial power is failure, or its voltage is too high or too low, it is able to keep voltage output within normal range. When commercial power is abnormal, it supplies power with battery by automatic switchover, and its response time is zero millisecond. The structure of the present invention is simple and its operation is stable. It has removed the power converter of UPS on the condition that all necessary features are maintained. The costs, volume, weight and power loss decrease to a percent of conventional UPS of same power.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an uninterrupted power supply without power loss. 
     2. Background 
     No matter it is an alternate current (AC) uninterrupted power supply (UPS) or a direct current (DC) uninterrupted power supply(UPS), it consists of a full power converter, which has two functions: one is to perform power conversion, and the other is to keep the voltage constant. The said full power converter is a DC-AC power converter or AC-DC converter with a power handling capacity constantly bigger than output power, while the deference between the power handling capacity and the output power depends on the specific efficiency. A conventional alternate current uninterrupted power supply (AC-UPS) (a power inverter) employs complex circuit and technology to export a constant sine wave voltage. The cost, volume, weight and power loss thereof is ninety nine percent of that of the complete appliance, respectively. In fact, once the stable current of UPS is transmitted into a computer and its peripheral, it is inversely converted, and the direct current voltage is rectified and filtered and then converted into the alternate current voltage. It is not the harmonics but the direct component of the alternate current voltage that the computer and its peripherals need truly. Thus it is unnecessary to invert the direct current into alternate current. At the same time, the harmonics of the alternate current become a major real and latent threat to the computer and its peripherals as well as an incipient fault of data security. Therefore, the optimum voltage for the computer and its peripherals is the direct current voltage. In addition, slow alteration of voltage with time does not produce any adverse effect on the operation stability of the computer and the peripherals. These appliances employ a regulated switch supply inside and don need any constant service voltage. They can run stably and reliably within the normal range of commercial power. 
     A recent invention of UPS Without Inverter (ZL97241194.1) has not any inverter of a conventional AC-UPS. It has realized the supply of direct current to a computer and its peripherals; it has been a great advance. Although it does not need a full power converter, it needs a compensating voltage to keep the direct current voltage output constant. If the alternate current voltage output varies within 20% of the direct current voltage output, it needs a DC—DC power converter whose power handling capacity is 20% of the full power. 
     Mission of UPS is: to keep the voltage output without interruption through supplying the power with battery in time by automatic switchover, before the commercial power is failure and the direct current voltage on the user appliance decrease to 75% of the power rating (usually 20 millisecond); and to keep the voltage output within the normal range when the voltage of commercial power is out of the normal range (too high or too low). Therefore, it is a necessary feature of UPS to keep the voltage output within the normal range, but it is a redundant feature to keep the voltage output constant. 
     Since the direct current power supply has significant advantages over an alternate current power supply, it is an unnecessary move to perform power conversion; since the computer and the peripherals can work stably and reliably within the normal range of commercial power, it is unnecessary to keep the voltage constant. It wastes ninety nine percent of the resources in the manufacture process of the power converter and ninety nine percent of the energy in the process of operation. It is clearly a redundant part of the UPS. There are limited resources on the earth. Energy is also in need. It is unnecessary to consume ninety nine percent of the resources and energy any more for the redundant feature. 
     SUMMARY OF THE INVENTION 
     The present invention is intended to overcome the above-mentioned disadvantages, and to remove the power inverter of a conventional UPS while at the same time keep the necessary features, and get rid of the redundant features to approximate an efficiency of a hundred percent and reduce the cost, volume and weight to one percent of the original one. 
     The aims of the present invention is realized through the following program: the UPS has radio frequency filter, rectifier filter and battery; the rectifier filter employs semi-controlled bridge circuit; after rectifier filter is the detecting circuit, controlling circuit and trigger circuit. The semi-controlled rectifier bridge B 1  is used for full-wave rectification and the direct current voltage output thereof as well as the direct current voltage output of the battery are transmitted directly into user appliances without any power conversion. 
     The direct current voltage output of the rectifier filter is sent out from Pin D 4  of the diode. The direct current voltage output of the battery is sent out directly from the silicon control SCR 3 . The voltages of them are both around 300 volts and loaded on the output ports at the same time. When commercial power is failure, or its voltage input is lower than the set value (for example, 176 VAC), SCR 3  is on state, and the voltage of the battery is loaded on the output port in 40 milliseconds (the conducting duration of the silicon control is no more than 40 milliseconds). When the voltage input is higher than the set value (for example, 264 VAC), SCR 1  and SCR 2  is cut off, the rectifier filter has no output, and thus the high voltage is cut off; at the same tine SCR 3  is on state and the voltage of the battery is loaded on the output port. Therefore, the voltage output can always be kept at around 300 volts no matter the commercial power is failure or its voltage is too low or too high. 
     The uninterrupted power supply without power loss has the following advantages: 
     1. it has a power consumption commensurate with that of a PN junction of a semiconductor. The overall efficiency of the complete appliance approximates a hundred percent. Thus it is an energy-saving product in the true sense. 
     2. the cost, volume and weight decrease to a percent of those of conventional UPS, respectively. It saves ninety nine percent of the resources. Thus it is truly an environmental protection product. 
     3. it has no problem of frequency instability or harmonic interference. With the uninterrupted power supply without power loss, the computer and its peripherals work more stably, and processing and transmitting of data become more save and secure. 
     4. it can employ natural wind cooling and does not need any rotating heat sink since the heating effect of the complete appliance is low. Thus the dependability is significantly enhanced. Furthermore, no error will happen to the complete appliance in the serviceable life because it has reduced ninety nine percent of the parts of the appliance. 
     5. simple design, easy manufacture and convenient generalization. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings which illustrate the best modes presently contemplated for carrying out the present invention: 
     FIG. 1 is a block diagram of an uninterrupted power supply without power loss; 
     FIG.  2 . is a main circuit diagram, including radio frequency filter, rectifier filter and battery; 
     FIG. 3 is a schematic diagram of detecting circuit; 
     FIG. 4 is a schematic diagram of controlling circuit; and 
     FIG. 5 is a schematic diagram of trigger circuit. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to the figures where like elements have been given like numerical designations to facilitate the reader&#39;s understanding of the present invention, and particularly with reference to the embodiment of the present invention illustrated in the attached figures, the preferred embodiments of the present invention are set forth below. 
     In the block diagram of FIG. 1., a cleaned alternate voltage is obtained after the voltage input passes through radio frequency filter. After passing through the rectifier filter, the obtained voltage turns into a direct current voltage Vo that changes slowly with time, and supplies the load current and the charge current at the meantime. The detecting circuit perceives various changes of the voltage input, voltage output and battery voltage, and then feed the information of these changes to the controlling circuit. The controlling circuit interprets the information and then produces signals of status display and aural warning and trigger, the trigger signal activates the silicon control to control the on state and off state of voltage input Vi and battery voltage E 1  appropriately in time. 
     In the main circuit diagram of FIG. 2., the protector F 1 , capacitor C 1 , C 2 , C 3 , C 4  and C 5 , and inducers ID 1 , ID 2 , and ID 3  constitute radio frequency filter. The diode D 1  and D 2  are connected in series, the silicon control SCR 1  and SCR 2  are arranged in series, the battery E 1 , electric resistor R 1 , and diode D 3  are connected in series, and then the four series arms are installed in parallel, wherein each of the positive poles of D 1 , D 2 , SCR 1  and SCR 2  is upward; each of the positive poles of D 3 , D 4 , E 1  and C 12  is downward; the positive pole and negative pole is connected to the negative pole of C 12  and the negative pole of E 1 , respectively; the first two series arms constitute the semi-controlled rectifier bridge B 1 , and the voltage output of the complete appliance, Vo, is obtained from the two ports of C 12  via resistor R 3  and protector F 2 ; electronic resistor R 4 , silicon control SCR 4  and SCR 5  are connected in series, the positive poles of SCR 4  and SCR 5  are upward, one end of R 4  is connected to the positive pole of E 1 , and the negative pole of SCR 5  is connected to the negative pole of E 1 ; the positive pole and negative pole of the electrolytic capacitor C 14  are connected to the negative poles of SCR 4  and C 12 , respectively. The semi-controlled rectifier bridge B 1  and the other full-wave rectifier filter bridge circuit composed of rectifier bridge B 2 , electrolytic capacitor C 13  and electric resistor R 2  are both connected to the output ports of radio frequency filter. The detecting voltage VT is obtained from the output ports of B 2 . The resistor R 3  is connected to the negative terminal of the output circuit and provides the current A 0  to sample the voltage. In FIG. 2., there are four groups of detecting voltage outputs: voltage outputs +V 0 , −V 0 ; battery voltages +E 0 , −E 0 ; current outputs +A 0 , −A 0 ; and voltage inputs +VT, −VT. 
     The detecting circuit in FIG. 3 consists of six detecting channels with identical structure. In the first channel, the positive pole of the light-emitting diode of the light electric coupler OPT 1  is connected to +VT through resistor R 7 , and the negative pole is connected to T through the potentiometer W 1 , the emitter electrode of OPT 1  triode is connected to the base electrode of triode T 1 , the emitters of them are grounded though resistors R 6  and R 5  respectively, and the collector electrodes of them are all connected to +17 V; Pin  2  and Pin  6  of the controlling circuit U 1  are connected to emitter electrode of the triode T 1  through resistors R 8  and R 9 , and at the meantime are grounded through potentiometers W 2  and W 3 , Pin  1  of U 1  is grounded, Pin  5  is grounded through electric capacitor C 6 , Pin  4  and Pin  8  are connected to +5 V, and Pin  3  produces output signal VIH. 
     The second detecting channel is connected to signal VT, which consists of OPT 2 , T 2 , U 2 , W 4 , W 5 , W 6 , R 10 , R 11 , R 12 , R 13 , R 14  and C 7 ; the third detecting channel is connected to input signal V 0 , which consists of OPT 3 , T 3 , U 3 , W 7 , W 8 , W 9 , R 15 , R 16 , R 17 , R 18 , R 19  and C 8 ; the fourth detecting channel is connected to input signal A 0 , which consists of OPT 4 , T 4 , U 4 , W 10 , W 11 , W 12 , R 20 , R 21 , R 22 , R 23 , R 24  and C 9 ; the fifth detecting channel is connected to input signal E 0 , which consists of OPT 5 , T 5 , U 5 , W 13 , W 14 , W 15 , R 25 , R 26 , R 27 , R 28 , R 29  and C 10 ; the sixth detecting channel is connected to input signal E 0 , which consists of OPT 6 , T 6 , U 6 , W 16 , W 17 , W 18 , R 30 , R 31 , R 32 , R 33 , R 34  and C 11 . The four signals of the detecting circuit from the main circuit, V 0 , E 0 , A 0  and VT, produce six output signals: high input voltage VIH, low input voltage VIL, high output voltage VOH, high output amperage AOH, low electric potential of the battery EL and very low electric potential of the battery ELL. 
     Model number of OPT 1  is  4 N 26 , wherein signals are inputted into the light-emitting diode through R 7  and W 1 . Some of the signals are high voltage. Some of the signals are low voltage. Obtain different step-down voltages of R 1  and then regulate W 1  to accommodate it to input signals of different voltage classes and optimize the current of OPT 1  light-emitting diode. The triode T 1  is 2SC733, which together with R 4  constitutes an emitter follower and produces the first-order current amplification. Model number of the controlling circuit is NE555, wherein Pin  2  and Pin  6  are connected to the emitter electrode of T 1 , and R 8  and R 9  are isolating resistors. The adjusting arm of W 2  is positioned at a place corresponding to the set value of voltage input Too High and the position of the adjusting arm of W 3  corresponds to the set value of voltage input Not High The output signal VIH can be adjusted to a transition point corresponding to the value between Too High and Not High by regulating W 2  and W 3 . It can be leant from the input and output logic relationships that: the output signal is Active-Low when it is to detect the input signal oo High and the output signal is active-High when it is to detect the input signal Too Low wherein VIH, VOH and AOH are all active-low and VIL, EL and Ell are all active-high. 
     Controlling circuit in FIG. 4 consists of U 10 A, U 10 B and U 10 C, two-input AND-NOT gates U 11 A and U 11 B, two-input NOR gate U 12 A, two-input AND gates U 7 A, U 7 B, U 7 C, U 7 D, U 8 A, U 8 B and U 8 C, and NOT gates U 9 A, U 9 B, U 9 C and U 9 D, which produces five trigger signals TRIG 1 -TRIG 5 , and four signals controlling the illuminating status of indicator light: ok for the complete appliance ALLOK, battery discharging EON, normal input voltage VOOK and normal voltage output VIOK, and one control signal to activate aural warning SPK 1 ; and the logic equations to produce the above-mentioned ten signals are: 
     
       
         TRIG 1 =TRIG 2 =!(! VIH#!VOH#!AOH );  
       
     
     
       
         TRIG 3 =TRIG 4 = EON =!( AOH#! VOH#! VIH &amp;  VIL#ELL );  
       
     
     
       
         TRIG 5 =!( VIH &amp;! VIL#AOH &amp;! ELL &amp; VOH );  
       
     
       ALLOK =!(! AOH# VOH# VIL#! VIH# ELL# EL ); 
     
       
           VOOK =!(! AOH#!VOH );  
       
     
     
       
           VIOK =!(! VIH#VIL );  
       
     
     
       
           SPK =!(! EL &amp;! ELL ).  
       
     
     The above logic equations are written in the hardware description language ABEL, a commercially available programmable language. In the ABEL language, the symbol “!” represents a logical complement or inversion operation, the symbol “&amp;” represents a logical AND operation and the symbol “#” represents a logical OR operation. The circuit in FIG. 4 passed the third-order simulation of the Abel language, wherein the U 7 A and U 7 B are two redundant gates that can reduce the time difference of signals TRIG 1 -TRIG 5  to reach the triggered silicon gate. 
     The switch supply SW 1  provides the controlling voltage for the complete appliance, wherein the positive pole thereof is connected to +E 0  through resistor R 35 , the negative pole thereof is connected directly to 0, and an electrolytic capacitor C 15  is connected between the positive and negative pole. There are two groups of voltages on the input port, +5 V and +17 V, with the common ground GND. 
     The trigger circuit in FIG. 5 consists of five groups of circuits with identical structure, wherein each group has a +17V independent direct current voltage provided by a switch supply and the positive poles and the negative poles of those switch supplies are connected to +E 0  and 0, respectively. For the first group of triggered silicon control SCR 1 , the negative pole of the switch supply SW 6  is connected to the negative pole K of the silicon control SCR 1 , and the positive pole thereof is connected to the collector electrode of the light electric coupler OPT 11  triode and the collector electrodes of the triodes T 15  and T 16 ; the negative pole of the OPT 11  light-emitting diode is grounded through potentiometer W 23 , the positive pole thereof is connected to control signal TRIG 1  through resistor R 55 , the emitter electrode of OPT 11  triode and those of T 15  and  16  are connected to the control electrode of silicon control SCR 1  at the meantime through resistors R 54 , R 53  and R 52 . The model number of OPT 11  is  4 N 26 . Change the trigger current flowing through SCR 1  by regulating W 23 . The model numbers of the triodes T 15  and T 16  are 2SC733 and 2SC5250, respectively. They together with R 53  and R  52  constitute an emitter follower to provide second-order amplification of electric currents. 
     The second group of circuits consist of light electric coupler OPT 10 , triodes T 13  and T 14 , potentiometer W 22 , resistors R 8 , R 49 , R 50  and R 51 , and switch supply SW 5 ; the third group of circuits consist of light electric coupler OPT 9 , triodes T 11  and T 12 , potentiometer W 21 , resistors R 44 , R 45 , R 46  and R 47 , and switch supply SW 4 ; the fourth group of circuits consist of light electric coupler OPT 8 , triodes T 9  and T 10 , potentiometer W 20 , resistors R 40 , R 41 , R 42  and R 43 , and switch supply SW 3 ; the fifth group of circuits consist of light electric coupler OPT 7 , triodes T 7  and T 8 , potentiometer W 19 , resistors R 36 , R 37 , R 38  and R 39 , switch supply SW 2 . 
     The trigger circuits produces five groups of trigger signals: SCR 1 -G, SCR 1 -K, SCR 2 -G, SCR 2 -K, SCR 3 -G, SCR 3 -K, SCR 4 -G, SCR 4 -K, SCR 5 -G, SCR 5 -K; these signals trigger the silicon control SCR 1 -SCR 5 , respectively. 
     The working process of the present invention is as follows: 
     First, the silicon controls SCR 1  and SCR 2  that constitute the semi-controlled rectifier bridge B 1  in the FIG. 2 is always on state when commercial power is normal. Actually B 1  is performing full-wave rectification. The pulsating voltage VD outputted therefrom is filtered by C 12  and then turns into a direct current voltage V 0  and outputted. At the meantime VD charges the battery E 1  through resistors R 1  and D 3 . The electric potential of E 1  is connected to the output port through SCR 3 . When everything is normal, the detecting circuit perceives VIH=1, VIL=0, AOH=1 and ELL=0. After these signals pass through the logic gates of the controlling circuit, the result is to get TRIG 1  and TRIG 2  that are high, and TRIG 3 , TRIG 4  and TRIG 5  that are low. Thus SCR 1  and SCR 2  are on state and SCR 3 , SCR 4  and SCR 5  are off state, and the voltage on the output port, V 0 , comes from the semi-controlled rectifier bridge B 1 . 
     Second, there are three cases when the electric potential of the battery is normal and the output ports are short-circuited: 
     1. When commercial power is failure, the detecting circuit perceives VIH=1, VIL=1, AOH=1, and ELL=0. After these signals pass through the logic gates of the controlling circuit, the result is to get TRIG 1 , TRIG 2 , and TRIG 3  that are high. SCR 1  and SCR 2  are off state because of no anode current. The commutating voltage VD equals zero. SCR 3  is always on state during the period. The electric potential of the battery E 1  is loaded onto the output ports. After commercial power supply restores service, VIL=0. After the signal passes through the logic gates of the controlling circuits, the result is to get TRIG 1  and TRIG 2  that are high, and TRIG 3  that is low, which is the same as the status before the power failure. At the moment when commercial power recovers, the direct current voltage V 0  after being rectified and filtered is bigger than the terminal potential of battery E 1  while SCR 3  is off state because of reverse bias. 
     2. When voltage of commercial power is too low, things are similar to those when commercial power is failure. What is different is that SCR 1  and SCR 2  are on state and the commutating voltage VD doesn equal zero. Since SCR 3  has been on state, on the positive pole of D 4  is the terminal potential of E 1 , which is higher than the commutating voltage VD on the negative pole of D 4  and thus D 4  becomes reverse biased. Thus the voltage on the output port comes from the E 1 . With the slow rise of the voltage of commercial power and the slow decrease of the discharge voltage of the battery, the voltages loaded on the positive pole and the negative pole of D 4  become very close to each other. On a certain moment, D 4  becomes forward biased, and then the current output is provided by both V 0  and E 0  at the meantime. When commercial power supply is on normal service again, SCR becomes off state because of reverse bias. 
     3. When the voltage of commercial power is too high, the detecting circuit perceives that VIH=0, VIL=0, AOH=1 and ELL=0. After passing through the logic gates of the controlling circuit, the result is to get TRIG 1  and TRIG 2  that are low, and TRIG 3  that is high, and there are no trigger signals on the controlling electrodes of SCR 1  and SCR 2 . When alternate current voltage crosses zero, they are automatically cut-off and thus the high voltage is cut off. During the process, SCR 3  is always on state, and the electric potential of battery E 1  is loaded on the output ports. When commercial power is normal again, VIH=0, then the signal passes through the logic gates of the controlling circuit and the result is to get TRIG 1  and TRIG 2  that are high, and TRIG 3  that is low, and it returns to the original state. 
     Third, there are two cases when the electric potential of the battery is normal and the output ports are short-circuited: 
     1. When the alternate current voltage is accidentally short-circuited, the detecting circuit perceives that VIH=1, VIL=0, AOH=0 and ELL=0, these signals pass through the logic gates of the controlling circuit and then get TRIG 1 , TRIG 2  and TRIG 3  that are low. Thus SCR 1 , SCR 2  and SCR 3  are cut off, and the voltage on the output port, V 0 , equals zero, so that the user appliance is protected. When the short circuit is relieved, AOH=1 and it restores the original state. 
     2. When the alternate current voltage is abnormal (the alternate current is failure, too low or too high), it can be learnt from the above that: before the short circuit happens, the electric potential of the battery is loaded to the output port through SCR 3 ; and after the short circuit happens, the detecting circuit detects that VIH=0 or VIL=1, AOH=0, and ELL=0, and then these signals pass through the logic gates of the controlling circuit to get TRIG 1 , TRIG 2  and TRIG 3 , that are low, and TRIG 5  that is high. Therefore, SCR 1  and SCR 2  are off state and SCR 5  is on state. Due to the on state of SCR 5 , SCR 3  becomes off state and the voltage on the output port V 0  is cut off, so that the user appliance is protected. When the short circuit is relieved, AOH=1 and it returns into the original state. Hereby, the process of off state of SCR 3  caused by the on state of SCR 5  is the same as that happens when the electric potential of the battery is too low. 
     Fourth, the electric potential of the battery is too low and the output port is short-circuited. When the alternate current voltage is abnormal (the alternate current is failure, too low or too high), SCR 3  is on state, the electric potential of the battery is connected to the output port. It can be learnt from the logic circuit in FIG. 4 that TRIG 4  and TRIG 3  change synchronously and therefore when SCR 3  is on state, SCR 4  is also on state, the potential of E 1  charges the C 14  through the series arm of R 4 , SCR 4 , C 14  and SCR 3 . When the charging current flowing through SCR 4  is lower than its sustaining voltage, SCR 4  is automatically off state and at the moment the potential that has been charged on C 14  is commensurate to that of E 1 . When the failure of commercial power lasts too long and the discharge voltage of the battery approximates the warning voltage, ELL=1. After the signal passes through the logic gates of the controlling circuit, the result is to get TRIG 5  that is high, SCR 5  is on state, and the positive potential on C 14  is loaded on the negative pole of SCR 3  through the forward direct current resistor of SCR 5 . Therefore, SCR 3  is cut off due to reverse bias, and the battery stops discharging to prevent the damages due to over discharging. 
     Fifth, charging and discharging of battery. The positive pole of the battery E 1  and the positive pole of semi-controlled rectifier bridge B 1  are connected to each other, and the negative pole of E 1  is connected to the negative pole of the B 1  through resistor R 1  and diode D 3 . The positive poles of B 1  and E 1  are connected to the output port. The negative pole of B 1  is connected to the output port through diode D 4 . The negative pole of E 1  is connected to the output port through silicon control SCR 3 . When commercial power is normal, B 1  charges E 1  through D 3  and R 1 . When E 1  has just finished discharging, the terminal potential is relatively low, the charging current is very high, and R 1  acts as a current limiting resistor. At the moment, charging of E 1  enters into the fast charging mode. When E 1  is about to be fully charged, the charging current diminishes, and the voltage drop on R 1  is so small that it has no effect on the charging circuit. At the moment, charging of E 1  enters into the floating charge mode. Since the filter electrolytic capacitor C 12  is connected to the left of D 4  and there is no electronic capacitor on the left, the voltage wave on the left and that on the right of D 4  are different: on the left is a single side pulsating sine wave VD with a frequency of 100 Hz and an amplitude of 308 V, and on the right is direct current voltage V 0  that changes slowly with time. V 0  fluctuates with the magnitude of voltage input and the load, but the charging voltage VD of the battery remains basically the same and is approximately equal to the amplitude of the alternate current voltage, which is mainly because the buffering action of D 3 , D 4  and SCR 3 . Only if commercial power is not failure, E 1  is always being charged and never discharges, and doesn fluctuate over time with the change of V 0 . Thus E 1  undergoes floating charge to a potential of 308 V or more than that and the state is continuously maintained. 
     Sixth, some points of explanation: 
     1. The aim of using a semi-controlled rectifier bridge is to cut off the high voltage fast once the voltage of commercial power is too high. If use a conventional rectifier bridge, an additional silicon control must be added apart from the rectifier bridge, and thus the power loss thereof doubles. 
     2. The SW 1  in FIG.  4  and the SW 2 - 6  in FIG. 5 are all low power switch supplies commercially available. Their power ratings are all within 10 W, and the powers of SW 2 -SW 6  are slightly different, depending on the trigger silicon control. For the micromidi uninterrupted power supply without power loss with the overall power of the complete appliance lower than 50 KW, SW 1 -SW 6  can be replaced by a switch supply with six independent coils. 
     3. When commercial power is out of normal range, SCR 3  becomes on state, and the electric potential of E 1  is loaded onto the output port. At the moment, E 1  undergoes free discharge. Apart from a 0.7 V voltage drop on SCR 3 , there are no other power losses. The efficiency=(308-0.7)/308=99.8%. The direct current voltage VD is directly outputted through diode D 4  after rectification. Therefore, the above equation of efficiency is also applicable to the case of normal commercial power supply. 
     4. The present invention keeps the necessary features of UPS entirely, while the main appliance is simple enough to have only several diodes and silicon controls, and get a 25 KW power output with rectifying parts of a current rating of 100 A. The efficacy corresponds to that of a 30 KVA conventional UPS. 
     While there is shown and described herein certain specific alternative forms of the invention, it will be readily apparent to those skilled in the art that the invention is not so limited, but is susceptible to various modifications and rearrangements in design and materials without departing from the spirit and scope of the invention. In particular, it should be noted that the present invention is subject to modification with regard to the dimensional relationships set forth herein and modifications in assembly, materials, size, shape and use.