WO1985002301A1

WO1985002301A1 - Method and device for supplying in emergency conditions a system from the mains

Info

Publication number: WO1985002301A1
Application number: PCT/FR1984/000257
Authority: WO
Inventors: Michel Chanavat
Original assignee: Cooperative D'avant Garde Pour Le Developpement De
Priority date: 1983-11-10
Filing date: 1984-11-09
Publication date: 1985-05-23
Also published as: FR2554991A1; JPS61500524A; EP0165938A1; FR2554991B1

Abstract

The device (100) according to the invention comprises a rectifier (110) to generate, directly from the mains, a high direct voltage; a high frequency direct-direct converter which generates the same high direct voltage from a buffer battery (130); a relieved power common line (150) receiving both high direct voltages thus generated; an inverter (160) of the direct chopping type to generate the alternating voltage for the system components requiring such a supply; a direct chopping supply (170) to generate the direct low voltage supply for the logic circuits. Thereby, there is no need for the inverter to be oversized since it does not withstand the maximum peak currents, very large, of the chopping supplies.

Description

METHOD AND APPARATUS FOR RESCUE-AETTING A SYSTEM FROM THE AREA

The present invention relates to a method and a device for emergency power supply to a system from the mains.

It finds its application each time it is necessary to supply a system (computer system for example, or even a programmed automaton) in a back-up fashion, that is to say a disturbance or a cut of the mains voltage. delivered by the electrical distribution network, at the input of the device, leaves unchanged the AC and DC supply voltages of the system, at the output of the device. The capacity of the back-up device in the event of a prolonged breakdown must be at least such that the powered system can implement procedures for backing up information or halting the peripheral organs aggressively, ^' in the case of a computer system .

The supply devices produced so far to fulfill this function are of the type shown in FIG. 1: the supply device 10 is inserted between the electrical distribution network (for example 220 V / 50H2) and the outlet mains voltage of the system supplied 20. It comprises a charger 11 for a buffer battery 12, which itself supplies an inverter 13 capable of producing an alternating voltage of the same effective value and of the same frequency as the sector.

To size this supply device, that is to say to calculate the power it must be able to deliver, it is necessary to consider not the effective intensity to be supplied to the powered system, but the maximum peak intensity that can be seen on the power line. It is indeed necessary to be able to respond to any significant current call from. system .. In particular, if one uses to produce the voltages continuous a switching power supply 21 or a ballast regulated power supply, very high peak currents are observed, inherent in the use of this very type of circuit. Thus, if we take the example of a system requiring 125 VA of average power in alternating current 220 V (for the supply of fans and a floppy drive motor for example) and 80 W of average power in direct current, it is necessary in practice to provide an inverter of power close to 1 kVA to maintain a sufficient reserve of power. In this example, we observe in particular with a switching power supply a maximum peak intensity of 5.5 A on the supply line, therefore corresponding to an instantaneous power much greater than the effective power requirements actually consumed.

Now inverters are devices whose efficiency is around 55 to 60% due to conduction and switching losses; this leads to large dimensions to ensure correct cooling of the semiconductors, a disadvantage which is added to that of electrical oversizing.

The invention proposes to overcome these drawbacks; it starts from the observation that, in the vast majority of cases, the power requirements are essentially DC power requirements. We have seen above that, in the conventional technique, the oversizing of the inverter results mainly from the intensity peaks produced by the switching power supplies, the sub-assemblies supplied with alternating

(mainly motors) being little subject to this kind of phenomenon. According to a first aspect of the invention, to supply the system on the one hand with alternating voltage of RMS value and frequency corresponding to those of a mains voltage, and on the other hand with at least one low DC voltage, we put implementing the steps consisting in: producing directly from the mains a high continuous voltage, producing on the other hand, from the low voltage of a buffer battery, a high continuous voltage of the same value as the previous one, delivering the two high continuous voltages thus produced on a common line of backed-up power, simultaneously producing, from the high continuous voltage present on this power line, the alternating voltage and the continuous supply voltage (s) of the system.

According to a second aspect of the invention, the device comprises: rectifier means for producing, directly from the mains, a continuous high voltage and delivering this to a common line of backed-up power, a DC-DC converter for producing, from the continuous low voltage of a buffer battery, a high continuous voltage, and deliver the latter also to the power line, the high continuous voltages delivered respectively by the rectifier means and by the DC-DC converter, having substantially the same values, buffer battery charger means, powered by the sector, a direct switching inverter, powered by the line of power, fear to deliver in crimped the alternating supply voltage of the system, a supply and regulation circuit, supplied by the power line, to deliver at output the (the) low (s) DC voltage (s) ( s) system supply.

Here and in the following, we will use the following definitions:

- "mains voltage": alternating voltage delivered by the electrical distribution networks. It is generally in Europe a voltage of 220 V effective at 50 Hz, but these values are not limiting; we can in particular consider a sector of 127 V / 60Hz corresponding to North American standards. - "Low continuous supply voltage": voltage whose value, positive or negative, corresponds to the supply needs of. logic electronic circuits (generally 5 V and 12 V) and the electrical or electromechanical devices which accompany them (generally 12, 24 or 48 V).

- "High DC voltage": voltage whose order of magnitude is that of a voltage obtained by simple rectification and filtering of an AC mains voltage, without the use of a DC-DC converter or other step-up or step-down means. This is for example a voltage of the order of 260 to 350 V for a mains voltage of 220 V rms.

- "Low continuous buffer battery voltage": voltage whose order of magnitude is that of the voltages of large capacity batteries commonly used as buffer batteries (generally 12, 24 or 48 V).

- "Direct switching inverter": inverter making it possible to produce an alternating voltage of effective value and of frequency corresponding to those of a mains voltage, directly from a high direct voltage and therefore without the use of voltage boosting means. Such an inverter is opposed to the conventional inverter supplied with low voltage, that is to say a voltage whose order of magnitude is that of the voltages of the buffer batteries.

Thus, according to the invention, the functions of a back-up supply of AC voltage are dissociated - produced by a low-power inverter permanently supplied but sized according to the only AC needs (therefore without significant power reserve). ) - and on the other hand back-up DC voltage supply - produced by a conventional switching power supply, but supplied with DC high voltage.

Continuous high voltage (back-up) is produced from the buffer battery by a DC-DC step-up converter, also of the conventional type.

The advantage is to only use sub-assemblies with very high efficiency and small dimensions, namely:

. a direct switching inverter (since it is supplied with high DC voltage): in addition to its higher efficiency (85%) than that of inverters supplied with low voltage, it is only dimensioned according to the AC requirements of the system supplied, no longer having to support the maximum peak currents of the feeders with uncoupling.

. a direct switching power supply, also supplied with direct current, a DC-DC converter which advantageously operates at a frequency at least equal to 20 kHz, which allows significant miniaturization and high efficiency. A subsidiary advantage of the invention is to allow the disconnection of the charger and the battery (for example for an exchange of the latter) during operation: the power line is indeed supplied with high continuous voltage (although not backed up ) by rectifying means. On the contrary, in the devices of the prior art, it is necessary to provide an additional switching in order to short-circuit the charger-battery-inverter assembly in the event of intervention. Furthermore, advantageously, the device comprises means for detecting disturbance or interruption of the sector, cooperating with the DC-DC converter so as to supply the latter only from the moment when a disturbance or a break is detected, the reserve time of the inverter and of the supply and filtering circuit being greater than the time of start-up of the DC-DC converter.

Other characteristics and advantages of the invention will appear on reading the detailed description below, made with reference to the appended drawings, in which:

. FIG. 1, already cited, is a schematic representation of a set of the prior art,

. Figure 2 is a schematic representation of an assembly according to the invention.

. FIG. 3 is a particular embodiment of the invention in accordance with the diagram of FIG. 2.

. The device 100 according to, the invention supplies the system 200 with alternating voltage (for example 220 V alternating for a power of 125 VA) and a plura dity of DC voltages (for example 5 V / 10 A, 12 V / 2 A and -12 V / 1 A, corresponding to an average total power of approximately 80 W).

The device 100 includes a rectifier 110 making it possible to obtain a direct voltage of the order of 260 to 350 V directly from the 220V sector. This high continuous voltage supplies a common power line 150.

Furthermore, a charger 120, also supplied by the mains, supplies a buffer battery 130 at a voltage of 48 V for example. This buffer battery is used to supply a DC-DC converter 140 delivering a high DC voltage at the same value (260-350 V) as that produced by the rectifier 110. This high voltage is also applied to the common line 150, from so that it can be indifferently supplied by the rectifier (normal operation) or by the buffer battery and the converter (emergency operation). Line 150 first supplies an inverter

160 with direct switching, that is to say which can directly transform the high direct voltage present on the line into an alternating voltage 220 V / 50 Hz corresponding to that of the sector and serving exclusively to supply the organs of the system 200 requiring a alternating current supply. The power of this inverter is therefore of the same order as that of the power actually consumed by these organs (125 VA in the example).

The line 150 supplies secondly a power supply 170, advantageously a direct breakdown power supply, which allows the direct transformation of the high direct voltage into a low voltage for the power supply of the electronic circuits. It is also possible to provide an extension 180 of this supply line 150 so as to supply other circuits with rescued continuous high voltage. Finally, to avoid permanently operating the converter 140, provision can be made to operate the latter only in the event of an actual cut. In this case, the response time of the control loop which starts the converter must be less than the reserve time of the inverter 160 and the switching power supply 170, for example a response time of 1 ms for a reserve of 20 ms.

The different sub-assemblies used can for example be of the following types, sold by the Applicant:

- for rectifier 110: RHDS type,

- for charger 120: type CBS,

- for the DC-DC converter 140: CCS type,

- for inverter 160: ODDS type,

- for switching power supply 170:. ADFE or ADMS.

FIG. 3 represents a particularly advantageous embodiment of the invention. In this figure, the same references as those used in Figure 2 represent the same elements. The buffer battery 130 supplied by the rectifier means 120 is directly connected to the common power line 150, the DC-DC converter 140 being omitted. In this case, the buffer battery 130 is a high voltage battery, capable of delivering a voltage between 260 and 350 volts continuous. The charging means 120 are adapted accordingly and allow the high voltage battery 130 to be charged at its nominal voltage. As further appears in Figure 3, the rectifier means 110 and the battery 130 are connected to the power line 150 respectively by a diode 111, 131. The operation of the device of Figure 3 will be described below.

Preferably, the nominal voltage of the high-voltage battery 130 can be chosen to be slightly lower than the direct voltage delivered by the rectifier means 110. When there is a mains fault, that is to say during an abnormal drop in the mains voltage, the direct voltage delivered by the rectifier means 110 becomes significantly lower than the nominal capacity of the high-voltage battery 130, which has the effect of causing the diode 111 to block, the conduction of the diode 131 and the supply of the power line by the high voltage battery 130. It will be understood that in the presence of a normal mains voltage, the conduction of the diode 111 and the blocking of the diode 131 ensures the supply of the power line 150 by the rectifier means 110. The embodiment of FIG. 3 allows the implementation of a backup system of simplified structure due to the elimination of the DC-DC converter 140.

The diode 111 can moreover be practically eliminated, the blocking function in the event of a mains fault being able advantageously to be ensured by the rectifier means 110.

Claims

1. A method for back-up supplying a system from the mains, on the one hand in alternating voltage of RMS value and frequency corresponding to those of a mains voltage, and on the other hand in at least one DC low voltage , characterized in that it consists of:. produce direct high voltage directly from the mains,. produce on the other hand, from the low voltage of a buffer battery, a high continuous voltage of the same value as the previous one,. deliver the two high continuous voltages thus produced to a common line of emergency power,. simultaneously produce, from the high direct voltage present on this power line, the alternating voltage and. the DC supply voltage (s) of the system.

2. A device (100) for implementing the method according to claim 1, characterized in that it comprises:

. means (110) for producing direct high voltage directly from the mains,. means (140) for producing, on the other hand, from the low voltage of a buffer battery (130), a high continuous voltage of the same value as the previous one,

. a common line (150) of emergency power receiving the two high continuous voltages thus produced,. means (160, 170) for simultaneously producing, from the high DC voltage present on this common line, the AC voltage and the DC voltage (s) supplying the system.

3. A device (100) for supplying a system (200) with backup power from the mains, on the one hand in alternating voltage of effective value and frequency corresponding to those of a mains voltage, device comprising rectifying means ( 110) to produce direct voltage directly from the mains and deliver to it a common line (150) of back-up power, a dc-dc converter (140) to produce, from the low dc voltage of a battery ( 130) a DC voltage and deliver this also to the power line (150) the DC voltages delivered respectively by the rectifier means and by the DC-DC converter having substantially the same values, charging means (120) of the battery buffer supplied by the sector and an inverter (160) supplied by the power line to deliver the AC supply voltage as an output, characterized in that the means s rectifiers (110) and the DC-DC converter (140) deliver a high voltage to the common power line (150), the inverter (160) being a direct switching inverter and in that the device also comprises a circuit (170) supply and regulation powered by the power line, to output one or more low DC supply voltages to the system.

4. A device according to claim 3, characterized in that the circuit (170) supply and regulation is a direct switching power supply.

5. A device according to claim 3, characterized in that the DC-DC converter (140) operates at a frequency at least equal to 20 kHz.

6. A device according to claim 3, characterized in that it further comprises means for disturbing or cutting the sector, cooperating with the DC-DC converter so as to supply the latter only from the moment when a disturbance or cut is detected , the reserve time of the inverter and of the supply and filtering circuit being greater than the time of start-up of the DC-DC converter.

7. A subassembly for a rescued device according to claim 3, characterized in that it comprises:

. rectifier means (110) for producing, directly from the mains, a continuous high voltage and delivering this to a common line (150) of back-up power,. a dc-dc converter (140) for producing, from the dc low voltage of a buffer battery (130), a dc high voltage, and supplying it also to the power line (150), the high voltages dies delivered respectively by the rectifier means and by the dc-dc converter, having substantially the same values,. charger means (120) of the buffer battery, supplied by the sector.

8. A device (100) for supplying a system (200) with backup power from the mains, on the one hand in alternating voltage of effective value and frequency corresponding to those of a mains voltage, device comprising rectifying means ( 110) to produce direct voltage directly from the mains and deliver it to a common line (150) of emergency power, charging means (120) of a buffer battery (130) to produce an emergency voltage, the charger means being supplied by the sector, and an inverter (160) supplied by the power line to deliver at the output the alternating supply voltage of the system, characterized in that the rectifier means (110) and the buffer battery (130) deliver a high voltage to the common power line (150), the inverter being a direct switching inverter, and in that the device further comprises a supply and regulation circuit (170) supplied by the power line to deliver one or more low DC supply voltages to the system.

9. Device according to claim 8, characterized in that the rectifier means (110) and the battery (130) are connected to the power line (150) respectively by a diode (111), (131).