GB2216277A

GB2216277A - Controlling and diagnosing the charge level of batteries

Info

Publication number: GB2216277A
Application number: GB8904771A
Authority: GB
Inventors: Gian Pietro Beghelli
Original assignee: GPB Beghelli SRL
Current assignee: GPB Beghelli SRL
Priority date: 1988-03-02
Filing date: 1989-03-02
Publication date: 1989-10-04
Anticipated expiration: 2009-03-02
Also published as: FI108322B; IT1219776B; IT8803355A0; FI890997A0; FR2628264A1; FI890997A; GB2216277B; FR2628264B1

Abstract

In an arrangement for controlling and diagnosing the charge level of batteries 10, 11 in a stand by power supply system, switches 8, 9, 12, 13 may be operated by a microprocessor control circuit 7 of a control and diagnosis circuit 6 whereby to connect individual batteries in turn, e.g battery 11 as shown, to a circuit 14 for both charging and discharging purposes. Each battery is diagnosed during a discharge cycle and may be re-charged accordingly. Batteries not being tested or charged at any moment remain on standby duty. <IMAGE>

Description

SYSTEM FOR MONITORING AtXD DIAGNOSING THE CHARGE LEVEL OF BATTERIES, PARTICULARLY FOR STkND-BY ELECTRICAL SETPLY tAITS The present invention relates to a sophisticated system for monitoring and diagnosing the batteries of a "stand-by" unit, i.e.

a unit able to ensure the continuity of the electrical supply to electrical machinery or plant and able to inform the user of the charge level and reliability of the batteries.

Electrical and electronic machines and plant are known whose continuous operation is essential even in the event of sudden failures in the supply from the normal electrical mains.

It is also known that in emergency situations resulting from the sudden failure of the mains voltage, so-called "stand-by" units automatically come into operation; these units are formed by blocks comprising a group of batteries, each having the same electrical voltage-. generally 12 V. The operating situation of the plant can usually be summarized by states in which mains voltage is present or absent: in the first case power is supplied from the mains to the user load and, through a voltage rectifier, for charging and maintaining the batteries; in the second case, triggered automatically when there is no mains voltage, the batteries supply electrical energy to an inverter which supplies the load without interruption.

In the current state of the art, the only solution to the problems of ascertaining the charge level of the individual batteries and thus finding out how efficient these devices will be when needed is to use inspection procedures which are not particularly reliable and are in any case very costly, for instance by carrying out a complete discharge cycle for the unit at periodic intervals, making use of the times at which the plant in question is least used and disabling the unit manually so that the whole unit can be replaced in the case of defects in a single battery which cannot be identified.This known system is therefore unsatisfactory both because during testing the stand-by unit is disabled and cannot perform its function in the event of a failure in the mains supply because of the inspection being carried out and because the possibility of ascertaining the actual level of efficiency and autonomy of the battery unit is reduced since it is impossible to locate the individual defective element.

According to the invention there is provided a control system as claimed in Claim 1 or Claim 6.

An example of the invention will now be described with reference to the accompanying drawings, in which Fig. 1 is a diagram of the components of the system with the stand-by unit and with the unit for monitoring and diagnosing the charge level; Fig. 2 is a diagram of the components of the battery unit circuit for the stand-by supply and the circuit providing for the monitoring and diagnosis of one battery in turn.

In normal conditions, the mains electrical supply supplies power to the load via the line or via the converter-inverter unit (see blocks 1 and 3) and simultaneously supplies a rectifier 1 designed to maintain the charge level of the batteries of the unit 2. In the absence of mains voltage, the battery unit 2 supplies power to the load via the inverter 3 with no interruption in the supply to the user.

The load is connected to the mains by the static by-pass 4 in order to meet current surge requirements and with the manual by-pass 5 designed to exclude the batteries during inspections and maintenance. The component 6 is a battery charge and discharge control circuit.

The battery circuit, in normal conditions of continuous supply, comes into operation in the absence of mains voltage. since the relays 8 and 18 are normally in the open position, and supplies the line via the series of individual batteries 10 of the unit2, the terminals of the line being supplied with an overall voltage which is a multiple of the individual voltages of the batteries.

As shown in Fig. 2, in which an operation to monitor the battery 11 is shown, the power relay 9 and the relay 13 modify their position and shut the battery 11 into a separate circuit. In this way the battery 11 is excluded from the circuit of the unit and the charge and discharge monitoring and diagnosis circuit 6, whose components form part of the prior art, is activated.

The block 6 comprises, in particular: - a test control citcuit 7 which, via a microprocessor, supplies control signals to a battery charger-simulated load circuit 14 and to the relays mentioned above.

This test control circuit 7 receives a clock signal 15 and a signal 16 showing the presence or absence of the mains supply.

- a battery charger-simulated load circuit which carries out the alternating functions of discharging the battery in reference conditions (constant current at a predetermined value) and recharging the battery.

This circuit is supplied by direct current from the rectifier bridge to the contacts 17, 17'.

The circuit group formed by the current integrator 18, operational amplifiers 19,19', DEnrX 20 and logic gates 21 supplies the user, via an LED display 22, with information on the result of the tests carried out by the system.

Subsequent operations are activated at the relay contactors 9 and 13, moving from the state shown at 8 and 12 by timers which manage the sequence of the operations to be carried out as a result of the pilot signals 23.

Acoustic and/or optical signals show any individual batteries whose efficiency is not normal.

The output signal 24 to the voltmeter is taken from the stand-by supply in Fig. 2.

It is evident that the periodic exclusion of one component from the battery unit does not entail any loss of reliability on the part of the system since the remaining elements are perfectly able to supply the electrical energy which may be needed in the event of a mains failure. The advantages of eliminating manual control by the operator and indentifying or replacing a single component of the battery unit rather than the whole unit are evident. It is necessary to discharge the battery since it is normally a lead battery and a measurement of voltage is not sufficient to assess its efficiency since the battery, even if defective, has a voltage equivalent to the nominal voltage at its terminals.

The present invention achieves the above objects and in particular makes the stand-by supply as reliable as possible through self-monitoring operations which do not affect the continuity or the efficiency of the system even temporatily and allows highly economic management without the need for costly operations, making it possible to replace a single component which is unrelIable.

Claims

CLAIMS:

1. A system for controlling and diagnosing the charge level of batteries particularly for stand-by electrical supply units, characterized in that it comprises a control circuit for charging and discharging the batteries mounted on a circuit-type support, the input and output signals of which regulate timed and sequential cycles involving the functions of monitoring and diagnosing the battery unit this diagnosis being based on an analysis of the behaviour of these batteries in respect of a controlled discharge.

2. A system as claimed in Claim 1, characterized in that a singe battery is subjected in turn to the monitoring and diagnosis cycle by energization or de-energization.

3. A system as claimed Claims 1 and 2, characterized in that the monitoring and diagnosis cycle is carried out without disabling the operation of the stand-by unit.

4. A system as claimed in the preceding claims, characterized in that the monitoring and diagnosis cycle is carried out automatically by suitable programmers and electrical timers, manual operation being needed only at the start and end of the cycle.

5. A system as claimed in the preceding claims, characterized in that acoustic and/or optical signals show the individual defective battery, allowing its elimination without disabling the operation of the stand-by unit.

6. A stand-by electric supply system comprising a plurality of batteries connectible to an output line, a discharge and recharge unit and means for disconnecting each battery in turn for a predetermined period from said output line and for connecting that battery to said unit while so disconnected.

7. A system as claimed in Claim 6 comprising means to sense the condition of the battery connected te said unit.

8. A system as claimed in Claim 7 comprising means responsive to the sensing means to maintain a said battery disconnected from said output line.

9. A stand-by electric supply system substantially as herein described with reference to the accompanying drawings.