Classifications

• • 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
  • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
  • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
  • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
  • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac 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
  • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac 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
  • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac 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 with automatic control of output voltage or current, e.g. switching regulators
  • H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac 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 with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
• • 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
  • H02M3/337—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 in push-pull configuration

Definitions

• the present invention relates to a device for increasing a direct-current voltage from a first value, for example 12 volts, to a second value, 24 volts.
• the device comprises a transformer or coil provided with an iron core and change-over devices.
• the device can be used as voltage doubler, for example for vehicles, weapons, etc.
• transformer arrangements are already known in connection with voltage conversion for increasing a direct-current voltage by means of counter electromotive forces that arise in the winding(s) during changes in current direction.
• the known equipment can comprise chokes and relatively large capacitors.
• the known equipment often comprises pure voltage regulators where there is a need for some form of filter arrangement for the outgoing voltage, which together comprises relatively large equipment with a large external volume.
• the principal characteristic of a device or transducer according to the invention is that the direct-current voltage with the first value is connected or is able to be connected to a central tap on the winding and that the ends of the winding are connected to change-over devices as mentioned in the introduction, which changeover devices are arranged to alternately bring about changes in potential of the said ends and thereby to create direct-current voltage pulses with the second value by means of the transformer's or the coil's counter electromotive force.
• the respective change-over devices comprise a pair of transistors.
• the respective change-over devices or pairs of transistors can thereby operate with a change-over ratio which is as close to 50% as possible, that is the distance between the outgoing direct current pulses is as short as possible without the danger arising that both change-over devices or pairs of transistors conduct at the same time with a resultant risk of damage.
• the said embodiments can also comprise the ends of the windings being connected to an output for the direct-current voltage pulses via diodes, which preferably consist of Schottky diodes or corresponding diodes.
• the output voltages on the cathode sides of the diodes are twice the direct-current voltage of the lower value minus the voltage drop across the respective diode.
• a smoothing choke can additionally be arranged before the winding's central tap in order to smooth the direct-current voltage of the first value.
• the device can additionally comprise a monitoring unit that ensures that the respective change-over devices or pairs of transistors conduct for such a long time during the generation of the direct- current voltage of the second value that it compensates for effects of any differences in resistance and/or inductance in the respective halves of the windings on the transformer and/or the resistances in the change-over devices or the pairs of transistors.
• the monitoring unit can also ensure that the change-over devices or the pairs of transistors work well when starting up.
• there is a regulator which is arranged to effect an optimal duty cycle for the direct-current voltage of the second value.
• a sawtooth voltage is used in the device, which sawtooth voltage controls the switching-on and -off times of the change-over devices or the pairs of transistors.
• the regulator or monitoring unit can thereby affect the gradient of the sawtooth voltage in such a way that the change-over time for the respective change-over device or pair of transistors assumes a value that allows the changes in the magnet flows to be equally large for the respective change-overs.
• the regulator can also detect current in the winding halves of the transformer or coil, for example by means of two measuring resistances or corresponding devices. The voltage or voltages which thereby arise across the resistances or corresponding devices affect the switching-on and -off times of the change-over devices or the pairs of transistors and in this way prevent the maximal desired current value from being exceeded.
• a fault indication voltage generated by the regulator can thereby control the switch-off level in the respective change-over device or pair of transistors. Additional embodiments of the invention are apparent from the following subsidiary claims.
• a transducer is realized which in total gives small losses, as certain losses arise only in utilized diodes and change-over devices.
• the reduction of external dimensions is possible by the outgoing voltage not needing to be filtered to any high degree and by chokes and large capacitors being able to be eliminated.
• the transducer operates as a pure voltage doubler and therefore does not need to be provided with any complicated regulating function.
• technically well-tested components can be used.
• the transformer is constructed as a part of a circuit board, which guarantees a small external volume in total.
• Figure 1 shows in detailed schematic form a constructive embodiment of the invention
• Figure 2 shows in diagrammatic form the embodiment of a sawtooth voltage that is generated by a regulator incorporated in Figure 1 , wherein a first version of the sawtooth voltage is indicated by an unbroken line and a second version of the sawtooth voltage is indicated by a dotted line,
• Figure 3 shows in diagrammatic form the switching-off point that is determined by the sawtooth voltage and a switching-off level determined by a fault indication voltage
• Figure 4 shows in diagrammatic form the period times for a change-over device or a pair of transistors incorporated in Figure 1.
• a transformer is indicated by L1 and two Schottky diodes by D1 and D2.
• a regulator REG of type UC 2825 A which can be obtained on the general market.
• the device also comprises a switch output stage SSL, which in turn comprises two pairs of transistors Q1 , Q2 and Q3, Q4 arranged in switch connections.
• a monitoring unit OVE which can be considered to be incorporated in or to interact with the said regulator REG.
• the said monitoring unit comprises among other things a unit U1 and a transistor Q5.
• there is a smoothing choke L2 which is connected to the midpoint of the transformer L1.
• the transformer is a so-called autotransformer.
• the midpoint is indicated by M.
• the respective ends N, N' are pulsed by the pairs of transistors Q1 , Q2 and Q3, Q4 respectively.
• the duty cycle for the switching per transistor pair is to be as close to 50% as possible.
• An incoming voltage of +12 volts, that is the positive pole of a voltage source SK, is connected to the said midpoint M via the said smoothing choke L2.
• the said pairs of transistors Q1, Q2 and Q3, Q4 cause the winding ends N and N' respectively to be connected to zero potential NO and NO' respectively.
• the transformer is thereby connected in such a way that 50% duty cycle per pair of transistors can be obtained.
• the output voltage on the cathode side of D1 and D2 is thereby 2 times the input voltage minus the voltage drop across the diode D1 and D2 respectively. In the ideal case, no or little filtration of the output voltage is thereby required, as it is then in principle a pure DC voltage.
• the said outgoing voltage Eut is essentially equal to + 24 volts.
• the said regulator REG is set in such a way that the maximal duty cycle is attained without the pairs of transistors Q1 , Q2 and Q3, Q4 respectively through-conducting with damage as a result.
• the transistor Q5 also operates when starting up the device in such a way that the output stage has a soft start.
• the regulator REG brings about a sawtooth voltage and the unit U1 is arranged to affect the gradient of this sawtooth voltage in such a way that the switch times of the respective pairs of transistors are designed to permit the magnet flow changes through the iron cores of the transformer to be the same size when the output stage switches.
• the sawtooth voltage which is generated by the regulator together with the surrounding components shown in the figure controls in turn the on- and off-times of the switch transistors.
• the regulator REG operates with a current-limiting function where the current in the respective winding halves of the transformer L1 is detected by two measurement resistances.
• the on- and off-times of the switch output stage are affected by the voltage across these resistances in such a way that the maximal desired current value is never exceeded.
• the regulator REG comprises a comparator function (PWM comparator) to which connection is made via the inputs 1 and 7.
• the comparator function controls the abovementioned switch device's connections and disconnections via the output 14 of the regulator.
• the electromotive voltage Ein is connected to the inductance L and an outgoing voltage value (Eout) of 2 times Ein will thereby arise.
• the resistance measurement function (including R1 and R2) can thereby be implemented with the latter current and after measurement a high-pass function is arranged, and also an integration function, in which the capacitor C6 is involved.
• the integration function is obtained at the regulator's output 6 and forms the average value of the flow change during the respective half period.
• the said output 6 is connected to the input 7 and the connection point is also connected to the comparator function via the input 1 between the resistances R6 and R5, across which the said Eout is connected. If the flow increases linearly during a half period, it is sufficient if the average value of the flow ⁇ ⁇ the saturation value.
• the soft start function effected by the unit OVE is effected by means of the transistor Q5, the control input of which is connected across the resistance R7 and the capacitor C3.
• the resistances R13 and R14 are connected to the anode of the transistor, and one side of the capacitor C3 is connected to the connection point of the resistances R13 and R14.
• the cathode of the transistor is connected to the connection point of the resistance R4 and the capacitor C17, the other side of which in turn is connected to the capacitor C4 and also to the series-connected resistances R11 and R12.
• Figure 2 shows two different sawtooth voltages initiated by the regulator REG in Figure 1 , RT (indicated by an unbroken line) and RT (indicated by a dotted line).
• the choice of, that is the gradient of, the sawtooth voltage is selected by means of the unit U1 in the monitoring unit shown in Figure 1.
• the sawtooth voltage is related to a constant voltage level KN.
• a fault indication voltage emanating from the above irregularities in the transformer's resistance or inductance has caused a voltage level NKN which is changed in relation to the voltage level in Figure 2.
• This change or fault indication voltage controls the switch-off level in the pairs of transistors Q1 , Q2 and Q3, Q4 respectively.
• the switch-off points are indicated in Figure 3 by FP and FP' respectively, which are related to the sawtooth voltages RT and RT' respectively.
• the fault indication voltage on input 1 controls the switch-off level (0-50%). Normally, the voltage is just below 50%.
• the fault indication voltage tries to keep the output voltage in question constant.
• the pulse length depends partly on the gradient of the capacitor voltage VC6, and partly on the fault indication voltage (INV).

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Dc-Dc Converters (AREA)
• Ignition Installations For Internal Combustion Engines (AREA)

Priority Applications (2)

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Publications (1)

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Family Applications (1)

Country Status (4)

Citations (5)

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• 2000
  • 2000-05-11 SE SE0001733A patent/SE522758C2/sv not_active IP Right Cessation
• 2001
  • 2001-05-09 EP EP01930388A patent/EP1303904A1/en not_active Withdrawn
  • 2001-05-09 AU AU2001256919A patent/AU2001256919A1/en not_active Abandoned
  • 2001-05-09 WO PCT/SE2001/001008 patent/WO2001086793A1/en active Application Filing

Patent Citations (5)

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