GB2593048A

GB2593048A - Actuator and power supply

Info

Publication number: GB2593048A
Application number: GB2102207.4A
Authority: GB
Inventors: Gordon Andrew Watson Benjamin; Peacock Martin; Keith Parfitt Andrew
Original assignee: Amp Procurement Ltd
Current assignee: Amp Procurement Ltd
Priority date: 2020-02-18
Filing date: 2021-02-17
Publication date: 2021-09-15
Also published as: GB202102207D0; GB202002212D0

Abstract

An uninterruptible power supply 9 (UPS) for use in a hazardous environment. The UPS has an electrical input 13 for receiving AC input power and for transmitting and receiving control and monitoring information, and an electrical output 15 which provides power to a load. A backup power supply provides power to the UPS upon failure/interruption of the AC input power. The backup power supply has a rectifier 21, a battery with one or more cell 17, and an inverter 27 for converting the DC battery output to AC. A system monitor, e.g. a battery health monitor 23, controls switching of power upon failure. The UPS is preferably disposed within a cabinet 11. The load may be a valve, such that during a dangerous event, e.g. a fire, an actuator may open/close the valve without risk to human life.

Description

Actuator and Power Supply

Field

The present invention relates to a power supply and in particular to an uninterruptible power supply for the operation of actuators used in potentially hazardous and other environments.

Background

There are many workplaces which have the potential to be hazardous to human health and well-being, for example, oil rigs, power stations, mines, chemical plants, refineries and ships. Such locations may contain explosive or otherwise dangerous chemicals, fire hazards, have a flood risk or other hazard.

Where a person works at a location in one of these environments, they will require HVAC (heating, ventilation and air conditioning) systems to provide a safe supply of air to their location. HVAC systems comprise a network of conduits which circulate, heat and replace the air for use at locations in the hazardous environment.

Should a situation arise where a hazard presents itself in a location, it may be necessary to isolate that location from its surroundings. As well as the doors and passageways for human entry and exit, conduits which form part of an HVAC system must be closed and sealed to be gas and or watertight. In these circumstances, conduits are fitted with valves which effect a gas and/or watertight seal.

One problem associated with the control of valves in a hazardous environment is that, if a hazard has occurred, such as an accident or fire, the mains power source which controls the valve may have been interrupted. Whilst many such valves may be operated manually, in some circumstances, manual operation of the valve may risk serious injury or death. Accordingly, it is known to provide a back-up power supply which would take over in the event of failure of the main supply. In many cases a battery is used for this purpose.

Depending on the location, a battery power source may be used to power 5 several actuators employed to close a valve. These devices are known as uninterruptible power supplies (UPS).

However, known battery-based solutions have several problems associated with them. Poor battery performance accounts for around 20% of all functional UPS io failures. Adverse environmental conditions can shorten battery life; the life of a battery is cut approximately in half if the battery is stored consistently above room temperature.

Summary of the Invention

It is an object of the present invention to provide an improved uninterruptible power supply and which addresses the above problems.

In accordance with a first aspect of the invention there is provided an uninterruptible power supply (UPS) for use in a hazardous environment, the UPS comprising: an electrical input for, receiving AC input power which is supplied to a UPS output and for transmitting and receiving control and monitoring information; an electrical output which provides power to a load; a backup power supply which comprises, a rectifier for converting an AC input to DC, a battery with one or more cell, and an inverter for converting a DC battery output to AC; and a system monitor, wherein, upon failure or interruption of the AC input power, the battery discharges through the inverter to provide power to the UPS output.

Preferably, the AC input power is supplied directly to the UPS output.

Preferably, the AC input power is supplied to the battery for charging.

Preferably, the AC input power is connected to the battery via a switch.

Preferably, the system monitor comprises a battery health monitor.

Preferably, the system monitor comprises a system fault monitor Preferably, the system fault monitor monitors the AC power input.

Preferably the system fault monitor provides monitoring information to a central location via dedicated wiring..

Preferably the system fault monitor provides monitoring information to a user interface on the UPS.

Preferably the system fault monitor monitors UPS temperature.

Preferably the system fault monitor monitors to detect component faults.

Preferably, the battery health monitor comprises an electrical load through which the battery is discharged and from which the characteristics of the discharge are monitored.

Preferably the electrical load is Incorporated in the UPS.

Preferably the electrical load is connected to the battery via a switch.

Preferably the UPS is mounted within a cabinet.

Preferably the cabinet is constructed from steel.

Preferably the cabinet is substantially cuboid in the shape.

Preferably the cabinet has an access panel on the front face of the cabinet.

Preferably the cabinet further comprises vents.

Preferably, the vents are positioned on the access panel.

io Preferably, the cabinet further comprises a valve through which a fire retardant material may be injected into the cabinet.

Preferably, the fire retardant material is carbon dioxide.

Preferably, the cabinet further comprises mounting brackets positioned on the rear of the cabinet.

Preferably, the rectifier, inverter and battery are spaced apart inside the cabinet to disperse any heat generated by their operation.

Preferably, the rectifier inverter and battery are located on separate internal walls of the cabinet.

Preferably, the electrical input is located on the top of the cabinet.

Preferably, the electrical input comprises a single cable.

Preferably the electrical input is coupled to the UPS via a gland plate.

Preferably the UPS further comprises a temperature controller Preferably, the temperature controller comprises a thermostatically controlled heater.

Preferably the hazardous environment comprises a ship and the load is an actuator which closes a valve in a conduit through a bulkhead.

Preferably, the conduit comprises a duct in a heating, ventilation and air-conditioning system.

Brief Description of the Drawings

io The invention will be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a schematic diagram 1 of a UPS in accordance with the present invention coupled to a central power source and a load; Figure 2 is a schematic diagram of a UPS in accordance with the present invention Figure 3a is a front perspective view of a UPS in accordance with the present invention and figure 3b is a front perspective view of the same UPS with front and top panels removed; Figure 4a is a front view of the UPS of figures 3A and 3B and Figure 4b shows the indicator panel 63 in more detail; and Figures 5a to 5i show an example of a circuit used to provide electricity to a load and to monitor the health of the battery in a UPS in accordance with the present invention.

Detailed Description of the Drawings

In the present invention, the UPS shall provide the capability to automatically close the valves following loss of connection to main power supply.

Figure 1 is a schematic diagram 1 of a UPS 5 through which power is provided from the control system 3 to a load seven. In the UPS of the present invention all power and control signals are routed through the UPS so as to provide a single point of control for the load.

Figure 2 is a schematic diagram of a UPS in accordance with the present invention. The UPS 9 comprises a cabinet 11 in which the components of the UPS are located. Whilst figure 2 is a schematic diagram, it does illustrate the feature that certain components of this example of the UPS are arranged on the outer walls of the cabinet 11. One reason for this is to separate heat generating components from one another as a passive means of controlling the temperature inside the cabinet 11.

Figure 2 shows and input connection 13 which is positioned on the top surface of the cabinet and which receives an input signal from a central location. The input signal comprises a power signal for the load and communication signals which allow the UPS to send battery health information back to the central location. The output 15 is connected to the load directly and is also directly connected to the input power signal and to the battery from where it can supply an alternative power source to the load.

The UPS also contains a plurality of cells which form the battery 17 which, as stated above, forms the alternative power source should the main power source be interrupted. The UPS also contains a battery health monitor 23. The purpose of the battery health monitor is to notify the operator that the battery has deteriorated and needs replaced or ensure that the UPS will remain operable should there be an interruption in the main supply.

The health of the battery is checked using the health monitor 23 at predetermined time intervals. The time intervals are selected based on the known characteristics of the battery such as the normal discharge rate, its response to changes in ambient temperature and others. The present invention allows for frequent battery health checks. Advantageously, it allows this process to be carried out entirely within the UPS because the UPS contains a health monitor load 25 through which the battery may be discharged as and when required. Should, for example, the temperature inside the UPS be consistently above or below a predetermined value, the present invention is able to quickly io and easily perform a health check using the health monitor load 25. Figure 2 also shows a rectifier 21 which converts an AC input current into a DC current and an inverter which converts the DC current from the battery into an AC current which is supplied to the load via the output 15. In another embodiment, it is programmed to carry out health checks at fixed intervals and report on the state of the battery via the connected LEDs and to report a detected fault via the digital output.

Heater 29 is provided with a temperature sensor such that if the temperature within the UPS cabinet 11 drops below a predetermined level the heater will come on to prevent condensation and be switched off once the temperature approaches or exceeds a second higher level. Bus 19 is provided as a means for connecting all of the components in a suitable and efficient manner.

Figure 3a is a front perspective view of a UPS in accordance with the present invention and figure 3b is a front perspective view of the same UPS with front and top panels removed. Figure 3a shows a cabinet 33 with a detachable front panel 35. The front panel has a handle 37 to assist with removal of the front panel 35. Four vents 39 are shown spaced across the front panel. The vents may contain high specification dust and particulate filters to ensure that cooling air may enter the UPS but the amount of particulate material which enters is minimised. The front panel also has a CO2 inlet 41; CO2 is used as a flame suppressant in the event of fire.

The cabinet also has mounting brackets 45 which are designed to minimise transmission of shock and vibration to the Cabinet. The top surface of the cabinet 33 contains four lifting eyelets 49 and a gland plate 43 through which the electrical input to the UPS is run.

Figure 3B shows the front panel 35 and top panel 43 removed from the cabinet 33. In the case of both the front panel and the top panel, it will be noted that there is an overlap between or around the edges of the openings 47 and 51 which minimises the ingress of particulates and generally improves the seal on in the UPS cabinet 33.

The opening 51 exposes features of the UPS which are showing schematically in figure 2. The battery 55 is shown fixed to the bottom inside surface of the cabinet 33 the health monitor load 59 and rectifier 57 as shown fixed to the far side inside surface of the cabinet 33. The bus 61 and health monitor are mounted on racks which are connected to the rear inside surface of the cabinet 33. In at least one other embodiment, the monitor indicates other parameters such as charging, discharging through various sequences of flashing the LEDs Figure 4a is a front view of the UPS of figures 3a and 3b. Figure 4b shows the indicator panel 63 in more detail. Figure 4a shows the inverter 65 mounted on the inside side wall of the cabinet 33 along with the other features shown in figure 4a. The indicator panel of figure 4b shows a series of indicator lights. These are rectifier fault 69, inverter fault 71 mains fail 73, heater on 75. Heater switch 77 and lamp test button 79 also shown. The right-hand side of the indicator panel 63 contains the battery health warning lights. The green light 81 signifies good battery health, the amber light 83 signifies intermediate battery health and the red light 85 signifies poor battery health and an urgent need to replace the battery.

Figures 5a to 5i show an example of a circuit used to provide electricity to the load and to monitor the health of the battery in a UPS in accordance with the present invention. The separate figures represent different modes of operation of the UPS and therefore identical reference numerals are used for identical features in each of the figures. In some of the figures reference numerals are omitted for the sake of clarity and the features of the circuit will be described with respect to figure 5a with additional features and functionality described with reference to the remaining figures 5b to Si.

Figure 5a shows a circuit 91 which comprises a power and communications input 92 which is connected directly to the output 94 via connection 109 and is also connected to the rectifier 93. The rectifier converts the AC input signal to a io DC signal for charging the battery 105. The connection between the rectifier 93 and the battery 105 contains a switch in a first position 95 which is connected to the rectifier and a second position 96 which allows the rectifier to be disconnected from the battery 105 and for the battery 105 to be connected to the health monitor load 97 during the process of checking the battery's health.

Also illustrated on the battery is a battery charge level 125. The battery is also connected to the inverter 107 which converts the DC output of the battery to an AC signal as an output from the UPS 94. The output is connected directly to the load which in this example is a valve 113. The health monitor load 97 is coupled to indicator lights 99, 101 and 103 which provide battery health information. As previously described the indicator lights are mounted on the external surface of the cabinet in which the UPS is contained.

Three inputs to an OR Gate 111 are shown. These inputs provide signals which act to close the valve by completing the circuit with the power source, either the main source at input 92 or the battery supply. Input 119 to the OR gate 111 is the input from the main power source 91, input 121 to the OR gate 111 is the emergency stop button input and input 123 to the OR gate 111 is a separate close valve input. The valve is closed when at least one of the inputs sends a signal to the OR gate.

Figure 5a shows the operation of normal charging of the battery. In this figure current is provided from the power and/or communications input 92 via the I0 rectifier 93 and switch 95 to the battery. The indicator light 99 shows that the battery is adequately charged.

Figure 5b is similar to figure 5a but shows a situation where the battery 105 is charged but is provided with a top up trickle charge 117.

Figure Sc shows a situation where a current is provided to the battery 105 from the input 92 via the other rectifier 93 to fully charge the battery. Accordingly, the state of charge of the battery 127 is shown as being lower than in figures 5a io and 5b. It is also noted that the green indicator light 99 is on, which shows that despite being low on charge the battery health is good. The LEDs will indicate the charging state.

Figure 5d shows a situation where the battery 105 is charged, the green indicator light is switched on 99 and OR gate 111 has received a signal from the close valve input 123 which acts to close the valve 113.

Figure 5e shows a similar situation except that, in this case, it is the emergency stop signal 121 that is live and this similarly causes the valve to be closed.

Figure 5f shows closure of the valve when the instruction is received and signal created via line 119. In this case, the mains supply has failed power to the output 94 is provided via the battery 105 which partially discharges through the inverter 107.

The discharge test is performed if the mains is healthy and the monitor has not picked up a problem with the battery, in which case an alarm will be signalled and no further tests will be carried out until the system has been reset and/or the battery changed.

Figure 5g shows operation of the circuit when the battery health is being checked. As can be seen, the switch moves to position 96 which disconnects the rectifier 93 and connects the load 97 to the battery and the battery is either

II

fully or partially discharged through the load 97. Data is collected on discharge rate and other battery health metrics to determine the health of the battery.

Figure 5h shows a situation in which the charge level of the battery is reduced 133 and displayed on the UPS as an amber warning light 101. Figure Si shows a situation where the charge level of the battery is seriously depleted 135 and this is shown as a red warning light 103 on the UPS.

In the above examples of the present invention, the power source is 230V, 1 io phase, 60Hz earthed platform electrical distribution system. Where there are a number of UPSs in a single vessel or other structure, they may be linked and provide the means for connection to the remote push buttons at a command station.

In at least one embodiment of the invention, the UPS shall be manufactured to a minimum protection rating of ingress protection IP56 which is an international standard which covers the protection of equipment from dust and jets of water from heavy seas. The cabinet is built to withstand all mechanical, electrical and thermal stresses which may arise from shock or vibration within a ship or short-circuit faults.

In use, one purpose of the present invention is to be able to ascertain the condition of the battery by a simple local visual or remote indication, showing whether the battery is healthy, nearing replacement or needs to be replaced 25 immediately.

The battery health monitor as used in at least one embodiment of the present invention will test and monitor the condition of the battery and indicate when the battery needs to be replaced.

This system will comprise the following: 1. Controller 2. Load Resistor 3. LED Output 4. Clean Contact Output 5. System Reset Input It is integrated into the UPS and operates as follows: 1. Under normal conditions the rectifier charges the battery and the Inverter is in standby/inhibit mode waiting for the actuator start signal.

2. When the signal is given, the existing AC supply closes an actuator. If there is no AC feed, the Inverter draws power from the battery and closes the actuator.

3. When the actuator is closed, the UPS returns to normal charging condition (if the AC feed is available.) The battery health monitor will be programmed with the unique characteristics of the actual battery used. This will include voltage range, capacity, temperature effects, life effects etc. In addition, the battery will be selected to have a long float life cycle, for example 15 years at 20°C, a long storage life of greater than 2 years at 25 °C, the capability of having good or excellent higher rate discharge, have wide operating temperatures -65°C to+80 °C, high shock and vibration resistance and a cycle life of up to 5000 cycles at 10% depth of discharge.

In at least one embodiment of the present invention, the system will use life cycle phases to indicate the condition of the battery. The final phase will indicate that replacement of the batteries is required. The coloured LEDs indicate the life cycle phase of the battery. Once the final phase is reached the battery test will be conducted two further times to verify the results.

A discharge test may be completed on a daily basis, the interval between tests may be changed, typically by changing the firmware. This will continue if the battery is suitable charged and the system condition is acceptable, that is: 1. The system has AC mains available; and 2. The battery condition is deemed to be healthy. In

In the event that the battery test cannot be undertaken, the system will check the condition three further times in order to conduct the test, after which a warning will be given to indicate charging or replacement is required.

In at least one embodiment of the present invention, the sequence of operation for battery testing is as follows.

1 The Charger/Rectifier will be disconnected from the battery. The charger will remain powered to provide the power feed for the controller.

io 2 If the charger feed is lost at any stage the system will immediately suspend the test and remove the test load.

3 The resistor load will be connected across the battery.

4 The battery will be discharged for a 10-minute period.

The temperature will be measured so results can be adjusted 6 The results of the test will be recorded and compared against battery data and previous test results; if results fall below pre-set limits, then the Amber-Red alarm will be given (otherwise the indication is Green). Alternatively, the system may use manufacturer data tables to assess the battery condition.

7 A visual and remote (via volt-free contact) indication of the battery health status will be given.

8 When the battery is replaced then the BHTM controller must be re-set via a pushbutton that will be in the cabinet, not accessible from the outside.

The present invention provides a UPS which allows battery testing using an internal source to monitor battery testing in safety critical locations where the provision of a power source to a load is safety critical. The UPS is configured to passively and actively adjust the heat in the UPS cabinet to maximise the performance of the battery, by for example, preventing condensation.

Improvements and modifications may be incorporated herein without deviating from the scope of the invention.

Claims

Claims 1. An uninterruptible power supply (UPS) for use in a hazardous environment, the UPS comprising: an electrical input for, receiving AC input power which is supplied to a UPS output and for transmitting and receiving control and monitoring information; an electrical output which provides power to a load; a backup power supply which comprises, a rectifier for converting an AC input to DC, a battery with one or more cell, and an inverter for converting a DC battery output to AC; and a system monitor, wherein, upon failure or interruption of the AC input power, the battery discharges through the inverter to provide power to the UPS output.
2. The uninterruptible power supply as claimed in claim 1 wherein, the AC input power is supplied directly to the UPS output.
3. The uninterruptible power supply as claimed in claim 1 or claim 2 wherein, the AC input power is supplied to the battery for charging.
4. The uninterruptible power supply as claimed in any preceding claim wherein, the AC input power is connected to the battery via a switch.
5. The uninterruptible power supply as claimed in any preceding claim wherein, the system monitor comprises a battery health monitor.
6. The uninterruptible power supply as claimed in any preceding claim wherein, the system monitor comprises a system fault monitor.
7. The uninterruptible power supply as claimed in claim 6 wherein, the system fault monitor monitors the AC power input. I5
8. The uninterruptible power supply as claimed in claim 6 or claim 7 wherein the system fault monitor provides monitoring information to a central location via dedicated wiring.
9. The uninterruptible power supply as claimed in claim 6 wherein, the system fault monitor provides monitoring information to a user interface on the UPS.
10. The uninterruptible power supply as claimed in claim 6 wherein, the io system fault monitor monitors UPS temperature.
11. The uninterruptible power supply as claimed in claim 6 wherein, the system fault monitor detects component faults.
12. The uninterruptible power supply as claimed in claim 5 wherein, the battery health monitor comprises an electrical load through which the battery is discharged and from which the characteristics of the discharge are monitored.
13. The uninterruptible power supply as claimed in claim 12 wherein, the electrical load is incorporated in the UPS.
14. The uninterruptible power supply as claimed in claim 12 wherein, the electrical load is connected to the battery via a switch.
15. The uninterruptible power supply as claimed in any preceding claim wherein, the UPS is mounted within a cabinet.
16. The uninterruptible power supply as claimed in claim 15 wherein, the cabinet is constructed from steel.
17. The uninterruptible power supply as claimed in claim 15 or claim 16 wherein, the cabinet is substantially cuboid in the shape.
18. The uninterruptible power supply as claimed in any of claims 15 to 17 wherein, the cabinet has an access panel on the front face of the cabinet.
19. The uninterruptible power supply as claimed in any of claims 15 to 18 wherein, the cabinet further comprises vents.
20. The uninterruptible power supply as claimed in claim 19 wherein, the vents are positioned on the access panel.io
21. The uninterruptible power supply as claimed in claim 19 or claim 20 wherein, the cabinet further comprises a valve through which a fire retardant material may be injected into the cabinet.
22. The uninterruptible power supply as claimed in claim 21 wherein, the fire retardant material is carbon dioxide.
23. The uninterruptible power supply as claimed in claims 15 to 22 wherein, the rectifier, inverter and battery are spaced apart inside the cabinet to disperse any heat generated by their operation.
24. The uninterruptible power supply as claimed in claims 15 to 23 wherein, the rectifier inverter and battery are located on separate internal walls of the cabinet.
25. The uninterruptible power supply as claimed in claims 15 to 24 wherein, the electrical input is located on the top of the cabinet.
26. The uninterruptible power supply as claimed in claims 15 to 25 wherein, , the electrical input comprises a single cable.
27. The uninterruptible power supply as claimed in any preceding claim wherein, the UPS further comprises a temperature controller
28. The uninterruptible power supply as claimed in claim 27 wherein, the temperature controller comprises a thermostatically controlled heater.
29. The uninterruptible power supply as claimed in any preceding claim wherein, the hazardous environment comprises a ship and the load is an actuator which closes a valve in a conduit through a bulkhead.
30. The uninterruptible power supply as claimed in claim 29 wherein, the conduit comprises a duct in a heating, ventilation and air-conditioning system.