WO1998059413A1 - Integrated uninterruptible power supply protection system with novel inverter circuit - Google Patents
Integrated uninterruptible power supply protection system with novel inverter circuit Download PDFInfo
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- WO1998059413A1 WO1998059413A1 PCT/CA1998/000602 CA9800602W WO9859413A1 WO 1998059413 A1 WO1998059413 A1 WO 1998059413A1 CA 9800602 W CA9800602 W CA 9800602W WO 9859413 A1 WO9859413 A1 WO 9859413A1
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
- H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
- H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
- H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/33561—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having more than one ouput with independent control
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
- H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
- H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
- H02J9/061—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems for DC powered loads
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
- H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
- H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
- H02J9/062—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems for AC powered loads
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
- H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
- H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/505—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means
- H02M7/515—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means using semiconductor devices only
- H02M7/521—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means using semiconductor devices only in a bridge configuration
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
- H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
- H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/505—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means
- H02M7/515—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means using semiconductor devices only
- H02M7/523—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means using semiconductor devices only with LC-resonance circuit in the main circuit
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
- H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
- H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
- H02M7/5387—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
- H02M7/53871—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration with automatic control of output voltage or current
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/32—Means for protecting converters other than automatic disconnection
Definitions
- the present invention relates to an integrated UPS and power supply system, in which the UPS comprises an inverter circuit for converting a DC voltage into an AC voltage.
- UPS Uninterruptible power supply
- off-line or standby line interactive
- on-line Off-line UPS systems
- off-line UPS systems do not regulate output voltage when the load is operating on utility power.
- off-line UPS systems are ineffective during power surges, spikes and brownouts, i.e. periods when a voltage reduction is initiated by a utility to counter excessive demand on its electric power generation and distribution system.
- an off-line UPS system requires a short transfer time before switching to battery power. These transfer times are typically several milliseconds, which makes off-line UPS devices unsuitable for use with sensitive equipment.
- Line interactive UPS systems regulate voltage by adjusting the utility voltage before it passes to the load, and thus provide protection during brownouts and against power surges and spikes.
- these systems still exhibit transfer times of the order of a millisecond, and therefore are also unsuitable for use with sensitive equipment.
- On-line UPS systems are connected between the power line and the load to provide for continuous voltage regulation and suppression of transients and noise.
- the transfer times for such systems are extremely small, and so they are suitable for very sensitive or highly critical equipment.
- on-line UPS systems provide for an improved and more efficient utilization of input utility power, and the improved power factor helps lower energy costs.
- UPS systems are particularly valuable with respect to computer systems since they provide users with data and equipment protection.
- a significant number of computer system breakdowns are caused by utility power failures and fluctuations, and this may require that expensive hardware be replaced and software reinstalled.
- Power problems also often lead to lockups, crashes, lost data, and faulty data transmissions.
- users need power protection to ensure that an electronic data transfer via the internet is properly completed, without any loss of data or sensitive information, even in the event of a power failure.
- a significant amount of time may be expended and business lost in attempting to recover from power disruptions.
- Computers also now perform multiple functions such as sending faxes and answering telephone calls, making the need for power protection even greater.
- power grids used by businesses may be more reliable than power grids for residential purposes, more and more people have begun working out of their homes.
- utility power supply in developing nations can be very inconsistent, with disruptions often occurring several times a day.
- a UPS system typically includes a storage battery, a battery charger, a switching circuit, and an inverter circuit which converts a DC voltage into an AC voltage.
- Conventional inverter circuits typically employ push-pull circuitry to alternately drive the two primary windings of a transformer and generate an alternating positive/negative or AC signal at the secondary windings of the transformer.
- This type of inverter is widely used in small and medium UPS systems (i.e. below 1 kVA (kilo- voltamperes)), as well as in other equipment which converts DC voltage to AC voltage.
- UPS systems i.e. below 1 kVA (kilo- voltamperes)
- in other equipment which converts DC voltage to AC voltage.
- UPS systems which incorporate these inverters are large, bulky, and generally unsuitable for use with personal computers, fax machines, and other equipment requiring small UPS systems.
- UPS technology While computer network server computer systems are often protected by UPS technology, this is much more rarely the case for individually based computers, despite the significant benefits provided by UPS systems.
- Current UPS technology is also expensive, particularly for on-line UPS systems.
- the present invention comprises an inverter circuit (10) for converting a DC voltage between a first DC input (14) and a second
- said inverter circuit (10) comprising (a) a bridge circuit (3) comprising a plurality of silicon controlled rectifier switches (SI, S2, S3, S4) arranged in a bridge configuration, said bridge circuit being coupled between said first DC input (14) and a first node (15), said bridge circuit further being coupled to said first output terminal (Ol) and said second output terminal (02); (b) a first pulse control circuit (1) responsive to a first pulse signal (II) and coupled to said bridge circuit (3) for turning on a first portion (SI, S3) of said bridge circuit (3);
- a timing circuit (4) coupled to said first and second pulse control circuits (1, 2) for generating the first pulse signal (II) for controlling said first pulse control circuit (1) and the second pulse signal (12) for controlling said second pulse control circuit (2), the first pulse signal and the second pulse signal being in phase opposition, characterized in that:
- the inverter circuit (1) further comprises a power switch circuit (5) responsive to a third pulse signal (13) and coupled between said first node (15) and said second DC input (16); and
- the timing circuit (4) is further coupled to the power switch circuit (5) and generates the third pulse signal (13) for controlling the power switch circuit (5).
- the present invention comprises an inverter circuit (10) for generating an AC voltage having first and second half cycles of opposite polarity and a wave form of a certain shape, said inverter circuit (10) converting a DC voltage between a first DC input (14) and a second DC input (16) into said AC voltage across a load (6), said load (6) being coupled between a first output terminal (Ol) and a second output terminal (02), characterized in that the inverter circuit (10) comprises:
- a bridge circuit (3) comprising a plurality of silicon controlled rectifier switches (SI, S2, S3, S4) arranged in a bridge configuration, said bridge circuit (3) being coupled between said first DC input (14) and a first node (15), said bridge circuit (3) further being coupled to said first output terminal (Ol) and said second output terminal (02);
- a first pulse control circuit (1) responsive to a first pulse signal (II) and coupled to said bridge circuit (3) for turning on a first portion (SI, S3) of said bridge circuit (3);
- a timing circuit (4) coupled to said first and second pulse control circuits (1, 2) and to said power switch circuit (5) for generating a first pulse signal (II) for controlling the first pulse control circuit (1), a second pulse signal (12) for controlling the second pulse control circuit (2), the first pulse signal(Il) and the second pulse signal (12) being in phase opposition, and a third pulse signal (13) for controlling the power switch circuit (5);
- said inverter circuit being configured such that said first pulse signal (II) pulses high and said second pulse signal (12) remains low during the first half cycle of said standard signal; said second pulse signal (12) pulses high and said first pulse signal (II) remains low during the second half cycle of the standard signal; said third pulse signal (13) pulses high if the value of said AC voltage is less than the value of said standard signal; and said third pulse signal (13) remains low if the value of said AC voltage is greater than the value of said standard signal.
- the present invention comprises an integrated uninterruptible power supply (UPS) and power supply system (50) for protecting a device from disruptions in utility AC power, said device having a power supply circuit (62) installed thereon for receiving utility AC power installed thereon, characterized in that said integrated UPS and power supply system comprises said power supply circuit (62) and an uninterruptible power supply system circuit (52), said uninterruptible power supply system circuit comprising a battery (58) and an inverter circuit (10), said inverter circuit not having an iron core transformer and being of small size.
- the integrated UPS and power supply system preferably comprises an inverter circuit in accordance with the present invention.
- Fig. 1 shows an inverter circuit which can be incorporated in a UPS system in accordance with one embodiment of the present invention.
- Fig. 2 shows one of the Pulse Control Circuits of Fig. 1.
- Fig. 3 shows the other of the Pulse Control Circuits of Fig. 1.
- Fig. 4 shows a possible Time Sequencing Circuit for the inverter of Fig. 1.
- Fig. 5 is a timing diagram for the circuit of Fig. 4.
- Fig. 6 illustrates an alternate embodiment of the inverter of Fig. 1
- Fig. 7 illustrates a further alternate embodiment of the inverter of
- Fig. 7a shows another embodiment of the inverter of Fig. 6.
- Fig. 8a and 8b illustrate waveforms for generating a sine wave output voltage.
- Fig. 8c illustrates the concept for generating the waveforms of Fig. Figs. 9a and 9b illustrate the basic concept of an integrated UPS and power supply system.
- Fig. 9c shows another embodiment of an integrated UPS and power supply system.
- Figs- 10 to 13 are detailed schematic circuit diagrams showing one implementation of an integrated UPS and power supply system.
- Figs. 14 and 15 are detailed schematic circuit diagrams showing an implementation of an integrated UPS and power supply system of Fig. 9c.
- Fig. 1 shows an inverter 10 in accordance with one embodiment of the present invention.
- the inverter 10 may be used in a UPS system.
- Inverter 10 comprises a full-bridge circuit 3 having a plurality (i.e. four) silicon controlled rectifier switches, or SCRs, SI, S2, S3, and S4, two pulse control circuits labelled 1 and 2 respectively, a time sequencing circuit 4, and a power switch circuit 5.
- the full bridge circuit 3 is connected directly to a positive DC input terminal 14 and is coupled through the power switch circuit 5 to a negative DC input terminal 16.
- rectifiers SI and S4 are positively connected in series between the DC input 14 and node 15, so that the anode of SI is coupled to the positive DC input
- Diode Dl is connected in parallel with SI so that the cathode of Dl is connected to the anode of SI and the anode of Dl is connected to the cathode of SI.
- Diodes D2, D3, and D4 are similarly connected in parallel across rectifiers S2, S3, and S4 respectively, as shown in Fig. 1.
- the gate and cathode of SCRs SI and S3 are connected to differential control voltage signals Ul and U3 which are generated by Pulse Control
- Time Sequencing Circuit 4 outputs three time- sequencing pulse signals: II, a first half-cycle time sequencing pulse which is the input to Pulse Control Circuit 1; 12, a second half-cycle time sequencing pulse which is the input to Pulse Control Circuit 2; and 13, a control time sequencing pulse which is the input to power switch circuit 5.
- 13 pulses low during the time between the first and second half-cycles (see Fig. 5 which will be described shortly and which shows waveforms for the signals II, 12, and 13 according to this embodiment).
- 13 may pulse high or low depending on whether the output voltage signal is greater or less than a reference waveform voltage signal.
- Pulse Control Circuit 1 has two pairs of mutually isolated terminals to output the control pulse signals Ul and U3
- Pulse Control Circuit 2 has two pairs of mutually isolated terminals to output the control pulse signals U2 and U4.
- pulse transformer Tl has one primary winding and two secondary windings, with the polarity marked terminal of the primary winding connected to a reference voltage +Vf and the other terminal of the primary winding connected to the collector of transistor Ql.
- transformer Tl need not comprise an iron core transformer.
- the emitter of transistor Ql is connected to ground as is one terminal of resistor R5.
- the base of Ql is connected to the other terminal of resistor R5 and to one terminal of capacitor C5.
- the other terminal of capacitor C5 is coupled to the input timing sequence pulse signal II.
- Diode D5 is connected in series with the first secondary winding of transformer Tl, and capacitor Cl and resistor Rl are each connected across the first secondary winding of transformer Tl in the manner shown in Fig. 2.
- Diode D6, capacitor C3, and resistor R3 are similarly connected to the second secondary winding of transformer Tl.
- Control pulse signal Ul is output across the terminals of Cl and Rl
- control pulse signal U3 is output across the terminals of C3 and R3.
- Pulse Control Circuit 2 The description of the configuration of Pulse Control Circuit 2 is the same as the above description for Pulse Control Circuit 1, with components C5, R5, Ql, Tl, D5, Cl, Rl, D6, C3, and R3 correspondingly replaced by C6, R6, Q2, T2, D7, C2, R2, D8, C4, and R4 respectively.
- power switch circuit 5 may comprise one power field effect transistor S5, wherein the grid or gate of S5 receives the time sequencing pulse signal 13 and thereby controls whether the channel between the source and the drain of S5, i.e. the control path, is conducting.
- Fig. 4 illustrates a possible embodiment for the Time Sequencing Circuit 4 and how time sequencing pulses II, 12, and 13 may be generated in this embodiment from the signal 10 which acts as an input to the Time Sequencing Circuit 4.
- the signals II, 12, and 13 may also be generated by a programmable microprocessor. This could also be achieved by a pulse current supply (not shown) as will be clear to those skilled in the art.
- circuit 20 generates complementary high/low signals 28 and 30 which are inverted (by conventional means not shown) every half cycle of 10.
- Circuit 20 may comprise a flip flop triggered by 10, or alternatively signals 28 and 30 may be generated by a programmable microprocessor.
- NOR gate 22 which outputs II
- the other signal 30 from circuit 20 and the signal 10 are inputs to NOR gate 24 which outputs 12.
- signal II pulses high during the first half cycle of 10, i.e the time period of tl + tO
- NOR gate 26 acts as a digital inverter which inverts the input 10 to produce pulse signal 13.
- transistor S5 In operation, during the onset of the first half cycle of 10 power transistor S5 is turned on by the rising edge of 13, and transistor Ql is turned on by the rising edge of II and conducts until the voltage at the base of Ql discharges, at a rate determined by R5 and C5, below the base-emitter threshold voltage.
- pulses are produced on each of the secondary windings of transformer Tl which charge Cl and C3 respectively through D5 and D6 respectively to a certain voltage.
- Ul and U3 reach the trigger voltage necessary to turn SI and S3 on, the output voltage across Ol and 02 becomes positive as shown for V0102 in Fig. 5.
- the load 6 has a high impedance which maintains a stable current when either of the switching device pairs S1-S3 or S2-S4 are conducting. This current through the load is greater than the holding current, which is the minimum current required to maintain the conducting SCRs in a conducting state after they have been turned on.
- power transistor S5 repeats the same turn on and cut off operation as just described for the first cycle, except in this case 12, and not II, pulses high when 13 goes high.
- Control pulses U2 and U4 eventually reach a level which turns on rectifiers S2 and
- the output voltage, V0102 is a two step per half cycle AC voltage signal.
- different output waveforms such as a sine wave, may also be produced by the inverter.
- a filter capacitor C7 is connected between output terminals Ol and
- Inductors LI and L2 and capacitor C7 thereby comprise a filter circuit which increases the duration of the rise and fall times of the output signal, thereby inhibiting high frequency components during the rising and falling edges of the output signal and consequently reducing interference with the load.
- inductors LI and L2 also serve to dampen the load current so that the circuitry can be protected.
- FIG. 6 an alternate embodiment of the power switch circuit 5 is shown comprising the power field effect transistor S5, a second power field effect transistor S6, current limiting resistor RIO, over current detecting resistor R9, gate or grid control resistor R7, gate or grid control transistor Q3, and resistor R8.
- RIO is connected between the drain terminals of S5 and S6.
- the source of S6 is connected to a first terminal of R8 and a first terminal of R9, while the second terminal of R9 is connected to the negative DC voltage 16.
- the first terminal of R8 is also connected to the source of S5 (so that the source of S5 is connected to the source of S6) and the second terminal of R8 is connected to the base of Q3.
- the emitter of Q3 is connected to the negative DC voltage 16 and the collector of Q3 is connected to the gate of S5 and a first terminal of R7.
- the input 13 is coupled to the second terminal of R7 as well as directly to the gate of S6. In this manner, the combination of RIO, S6, and R9 form a control loop or control path for the power switch circuit 5.
- the rising edge of the input pulse signal 13 simultaneously turns on power transistors S5 and S6.
- Resistor R9 samples the magnitude of the load current, and when the load current reaches a certain threshold magnitude, the voltage drop across R9 turns transistor Q3 on, which lowers the gate potential of power transistor S5, and in turn quickly leads to S5 shutting off. With S5 cut off, the load current shifts to flow through power transistor S6, whereby it is limited by the value of resistor RIO.
- the above described current limiting approach which does not entirely cut off the current loop, ensures that maximum power can be outputted while still maintaining safe operation of the circuitry.
- inductor L3 which is connected between terminal 15 and the power switch circuit 5, as shown at terminal 17.
- inductor L3 and capacitor C7 still comprise a filter circuit which increases the duration of the rise and fall times of the output signal, inhibiting high frequency components, and reducing interference with the load.
- Inductor L3 also serves to dampen the load current and thereby provide greater circuitry protection , as did inductors LI and L2 in Fig. 6.
- inductor L3 also provides protection in case a short results from SI and S4 simultaneously conducting or from S2 and S3 simultaneously conducting.
- Inductor L3 stops such a short current from increasing too rapidly, allowing (as explained above) the power switch circuit 5 to detect the high current, switch off transistor S5, and subsequently limit the current in the control path. Also in the embodiment of Fig. 7, diodes Dl, D2, D3, and D4 are replaced by one feedback diode D9 which provides a discharge loop for a load current when the power switch is off.
- Fig. 7a shows still another embodiment of the inverter circuit of the present invention.
- This embodiment includes the diode D9 of Fig. 7, the diodes Dl, D2, D3, and D4 of Fig. 6, as well as a resistor Rll in series with a switch S7.
- the resistor Rll and switch S7 together form a discharge path for the output load capacitance (including C7) at the falling edge of the output waveform.
- the switch S7 turns on after the switches S1-S4, as well as the switches S5 and S6, have turned off (i.e. have stopped conducting).
- the inverter circuit according to the present invention allows for the rise and fall times of the output waveform to be controlled. This can be accomplished by, for example, varying the value of RIO or C7 which together form a time constant for the output voltage signal. In the embodiment of Fig. 7A, the fall time could also be controlled by varying the value of Rll.
- the input capacitance may range from about 0.1 ⁇ F to about 0.47 ⁇ F.
- the rise and fall time constants range from 0.2 ms to 0.57 ms
- the rise and fall times range from about 0.5 ms to 1.5 ms (i.e. about 2.5 times the time constant).
- longer transition times inhibit high frequency components, such as noise, and reduce interference with the load.
- the inverter of the present invention can generate an output waveform which is a close approximation to a certain type of waveform, particularly a sine wave.
- Traditional methods of generating a sine wave output in a full-bridge inverter involve turning the four switches on and off at a high frequency. This operation is fairly complex and results in a high switching loss.
- the inverter By altering the signals from the Time Sequencing Circuit 4, the inverter according to the present invention can be used to produce a stepped or porch sine wave.
- the output voltage signal is continuously compared to a normalized or standard sine wave form signal of a certain frequency and amplitude.
- the II and 12 signals effectively pulse high during alternate half cycles of the standard wave signal: II pulses high and 12 remains low when the standard wave signal is positive and 12 pulses high and II remains low when the standard wave signal is negative (in practice there will be a very short time delay after one of these signals goes low before the other goes high).
- the 13 signal is essentially controlled by the principal of negative feedback. When the output voltage falls below the standard wave signal, 13 goes high turning on the power switch circuit 5 (and transistor S5).
- Fig. 8a illustrates the timing for the signals II, 12, 13 , and the output voltage signal V0102. As shown in Fig. 8a, the pulses of signal 13, which turn on the power switch 5, become narrower near the zero crossings and wider near the positive and negative peaks of the output signal.
- This method of output sine wave generation can be performed by a microprocessor which possesses an analog-to-digital (A/D) conversion function.
- Fig. 8c illustrates this concept generally.
- the output waveform can be sampled by a sampling circuit and A/D (conversion) port 200 in a microprocessor 202, and then compared by comparator function 206 to the numerical amplitude of the standard sine wave already stored in the microprocessor memory at 208.
- the microprocessor 202 (through control module 206) then generates the signals II, 12, and 13 in response.
- the present invention can also be applied to another method of generating a sine wave output voltage signal in which the inverter circuit no longer strictly converts a DC voltage to an AC voltage.
- the voltage at terminal 14 of the inverter circuit (or alternatively at terminal 16) is not a DC signal but resembles a fully rectified half sine wave signal, as shown in Fig. 8b.
- the signal at terminal 16 (or alternatively at terminal 14) remains a DC signal, and preferably is at ground level. It is again necessary, in this embodiment, to compare the output voltage to a standard wave form signal.
- a high power converter which is controlled by a microprocessor generates the voltage signal at terminal 14. In a well known manner similar to that just described for the method illustrated by Fig.
- the output of the high power converter is altered, in response to the results of this comparison, to more closely resemble a half or rectified sine wave voltage signal.
- the signals II, 12, and 13 may be generated as illustrated in Fig. 5, however tO, the time during which the power switch is shut off, is preferably very short in comparison with tl and t2.
- SCR silicon controlled rectifier
- the addition of the power switch 5, however, allows the current through the load 6 to be switched on and cut off, independently from the SCRs S1-S4, at a much higher rate than if the SCRs had to be turned off directly.
- the power switch eliminates the need to turn off a conducting SCR by, for example, connecting its gate and cathode. As discussed further below, this affords the benefits of high speed switching to the inverter circuit 10.
- the inverter of the present invention is capable of driving the SCRs S1-S4
- the SCRs S1-S4 also provide the benefit that, once turned on, they remain in their conducting state until the current through them drops below a certain threshold. Thus there is no need for a continuously applied driving signal to maintain the SCRs in a conductive state. The removal of this requirement reduces the complexity of the Pulse Control Circuits 1 and 2 of the present invention in comparison to prior art transistor based inverter circuits.
- the use of the power switch 5 is also highly advantageous with respect to waveform modulation of the AC output of the inverter.
- Waveform modulation is typically a requirement for inverter circuits, and is usually performed to approximate a sine wave, as described above.
- the AC output of the inverter requires low pass filtering, as effected, for example, by the elements C7 and LI and L2 in Fig. 6.
- greatly improved waveform modulation of the AC output is achieved by rapidly turning the power switch on and off at a rate much faster than the commutation rate of the SCR switches themselves.
- the inductor and capacitor which comprise the low pass filter for the AC output can be made much smaller, because the required cutoff frequency of the low pass filter is much higher.
- the transformers Tl and T2 which isolate the bridge circuit 3 from the pulse control circuits 1, 2 can also be made much smaller and less heavy because the transformers are only required to output very narrow pulse signals to turn the SCRs on. Therefore, the power switch 5 of the present invention permits the inverter circuit 10 to be much smaller in size and weight. This is in addition to the reduction in size and weight already obtained by using SCRs (S1-S4) as the switching elements instead of transistor type switches, as in the prior art. This capability for high speed switching, despite using switches (i.e. SCRs) which are not themselves normally capable of high speed switching, permits the inverter 10 which forms part of the present invention to be of very small size and relatively low cost.
- switches i.e. SCRs
- the inverter circuit according to the present invention does not comprise an iron core transformer and is capable of being designed so that its size and weight are compatible for use in small type UPS systems. Safe and reliable inverter operation is not compromised since the power switch circuit 5 acts to protect the entire system.
- the reduction in size of the UPS system further allows it to be conveniently integrated or merged physically with any conventional switch power supply, such as a PS/2 supply commonly used for personal computers.
- the UPS system according to the present invention is small and compact enough to be fitted into the power supply housing for the device itself. This is particularly beneficial, in terms of the design and portability of the device, for UPS systems which provide at least partial on-line protection and which must be at least partly connected between the utility power line and the load. This concept is illustrated, by way of example, in Fig.
- FIG. 9a which shows an integrated UPS and power supply system 50 (the modules of which are shown Fig. 9b) for a computer system 210 with a peripheral monitor 64.
- the circuitry for the UPS system including an inverter according to the present invention, can be physically combined on the same board 51 as the circuitry for the power supply.
- the housing of an integrated system 50 according to the present invention can be of a size: 150 millimetres in length by 150 millimetres in width by 85 millimetres in height (and with a printed circuit board 144 mm x 105 mm x 30 mm in size). This type of integration would not be possible for prior art UPS systems comprising inverters which use iron core transformers, without significantly increasing the size of the integrated device.
- the integrated system 50 can be conveniently installed in or on an electronic device, in some instance it may be preferable to make the system 50 externally connectable, for instance when the power capacity of a device is high and correspondingly a large battery is needed in the UPS circuit.
- Fig. 9b shows a block diagram which illustrates the basic concept of an integrated UPS and power supply system 50 designed to protect a personal computer system.
- the UPS system 52 generally comprises a relay
- the UPS system is connected through the relay 54 between the utility power line 70 and the load 64, which, in this particular case, comprises a computer monitor.
- the integrated system continuously converts AC to DC power to continuously provide the computer with clean regulated DC voltage signals.
- the integrated system of Fig. 9a provides double conversion to both ⁇ 5 volts DC and +12 volts DC.
- This form of online protection results in essentially a zero transfer time in the event of some sort of utility power failure or disruption.
- the monitor is not backed up by on-line protection (this is not necessary since the transfer time of a few milliseconds, the switching time of the relay, is not visually perceptible to a human user).
- the integrated system may provide complete on-line protection for a computer system or other electronic device.
- Fig. 9c shows another embodiment of the present invention comprising an integrated UPS and ATX computer motherboard power supply system.
- a PS-ON signal 90 from the motherboard (not shown) of the computer controls the normal DC output from 66 to allow for energy savings.
- a 5 V standby (SB) output 92 from DC /DC converter 67 is used to support various communication functions of the microcomputer, such as Wake on LAN, Wake on modem, soft power control, and so on.
- the converter 67 generates the standby output voltage 92 and the battery charger input voltage 94 as long as the integrated system is connected to the AC line 70.
- the DC/DC converter 60 has two outputs 96 and 98.
- the output 96 supplies the voltage VDC to the DC /DC converter 66, and the output 98 supplies the voltage VD or VDC/2 to the node between capacitors 68' and 68".
- a 220/110 AC Volt selector 59 determines whether the input to the inverter circuit 10 is VDC or VDC/2.
- Figs. 10 to 13 are schematic circuit diagrams showing a detailed implementation for the integrated UPS and power switch supply system 50 of Fig. 9b. The operation of Figs 10 to 13 will be well understood by those skilled in the art, and so these are described only briefly here.
- Fig. 12 shows the control block (including timing control) of the system comprising a microprocessor module 80.
- Fig. 13 shows the pulse control circuits 1 and 2 and the full-bridge circuit 3 of the inverter 10.
- Fig. 10 shows the remainder of the integrated UPS and power supply system including a standard power supply circuit 62, relay 54, converter 60, battery charger (voltage regulator) 56, and a 12 V battery 58.
- Fig. 10 also shows a circuit 74, a connector 72, and a buzzer device 76.
- Circuit 74 is an optional circuit designed to control the falling edge of the output signal, but which otherwise does not affect operation.
- Fig. 11 is a block diagram showing how Fig. 12, Fig. 13 and the connector 72 of Fig. 10 interconnect.
- Figs. 14 and 15 are schematic circuit diagrams showing a detailed implementation for the integrated UPS and power switch supply system 50 of Fig. 9c.
- the microprocessor increases and monitors overall performance of the inverter and battery. It also manages power consumption, temperature and output voltage.
- the microprocessor When the system 50 is connected to a computer the microprocessor enables the system to communicate with the computer, and it can also be programmed to protect all unsaved data before automatically shutting down the computer safely.
- the microprocessor also activates a continuous alarm when battery power is in use by sending an appropriate signal to the buzzer device 76. As the battery power becomes weaker the pitch of the alarm can be increased to inform the user to shut down the computer.
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU79034/98A AU7903498A (en) | 1997-06-20 | 1998-06-19 | Integrated uninterruptible power supply protection system with novel inverter circuit |
CA002290403A CA2290403A1 (en) | 1997-06-20 | 1998-06-19 | Integrated uninterruptible power supply protection system with novel inverter circuit |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA 2208380 CA2208380A1 (en) | 1997-06-20 | 1997-06-20 | Integrated uninterruptible power supply protection system with novel inverter circuit |
CA2,208,380 | 1997-06-20 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1998059413A1 true WO1998059413A1 (en) | 1998-12-30 |
Family
ID=4160921
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/CA1998/000602 WO1998059413A1 (en) | 1997-06-20 | 1998-06-19 | Integrated uninterruptible power supply protection system with novel inverter circuit |
Country Status (3)
Country | Link |
---|---|
AU (1) | AU7903498A (en) |
CA (1) | CA2208380A1 (en) |
WO (1) | WO1998059413A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2005004306A1 (en) * | 2003-07-03 | 2005-01-13 | Eppscore Co., Ltd | Uninterruptible power supply for the back up of ac-power supply |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4208711A (en) * | 1978-03-13 | 1980-06-17 | Exxon Research & Engineering Co. | Inverter with naturally commutated mixer |
US4410935A (en) * | 1981-03-23 | 1983-10-18 | General Signal Corporation | Current overload protection for inverter of uninterruptible power supply system |
-
1997
- 1997-06-20 CA CA 2208380 patent/CA2208380A1/en not_active Abandoned
-
1998
- 1998-06-19 WO PCT/CA1998/000602 patent/WO1998059413A1/en active Application Filing
- 1998-06-19 AU AU79034/98A patent/AU7903498A/en not_active Abandoned
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4208711A (en) * | 1978-03-13 | 1980-06-17 | Exxon Research & Engineering Co. | Inverter with naturally commutated mixer |
US4410935A (en) * | 1981-03-23 | 1983-10-18 | General Signal Corporation | Current overload protection for inverter of uninterruptible power supply system |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2005004306A1 (en) * | 2003-07-03 | 2005-01-13 | Eppscore Co., Ltd | Uninterruptible power supply for the back up of ac-power supply |
US7259475B2 (en) | 2003-07-03 | 2007-08-21 | Eppscore Co., Ltd. | Uninterruptible power supply for the backup of AC-power supply |
Also Published As
Publication number | Publication date |
---|---|
CA2208380A1 (en) | 1998-12-20 |
AU7903498A (en) | 1999-01-04 |
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