WO2003098791A1

WO2003098791A1 - Loop power system

Info

Publication number: WO2003098791A1
Application number: PCT/NZ2003/000096
Authority: WO
Inventors: Raymond Kaukohea Puna
Original assignee: Loop Power System Limited
Priority date: 2002-05-19
Filing date: 2003-05-19
Publication date: 2003-11-27
Also published as: NZ517292A; AU2003234370A1

Abstract

A power supply system arranged to provide electrical power, includes at least one battery, an inverter connected to the battery(s) and arranged to deliver output power calibrated to a predetermined level to a load, and a charger arranged to also receive a proportion of the output power of the inverter and provide charging power to the battery(s). Preferably the power supply is arranged so that the output load on the inverter comprising the output load on the power supply and the charger together, is limited to less than about 70% of the output load capacity of the inverter, and so that the output load on the power supply is limited to less than about 50% of the output load capacity of the inverter.

Description

LOOP POWER SYSTEM

FIELD OF INVENTION

The invention relates to a power supply system in which part of the load is used to supply power back to a power storage device of the power supply system.

BACKGROUND

Many systems currently exist for the generation of electrical power. These systems include hydroelectric, gas, coal and thermal power stations, wind turbines, solar panels and electrochemical generators such as batteries. All of these systems are open loop systems in which the energy generating the power is used only once. For example in a hydroelectric power station water moves downwards and its gravitational potential energy and kinetic energy are harnessed to turn turbines coupled to electrical generators. Once the water has passed through the turbines it no longer containing the gravitational potential energy it had before entering the hydroelectric power station. Similarly when wind turns a wind turbine the wind cannot be turned around to turn the turbine again without using more energy than is generated by the turbine.

Sustainable power generation is becoming more important in an age concerned about the environment and the effect of pollution generated by conventional power stations on the environment. Power generation systems using solar and wind power have already been invented but suffer from high costs and in some cases low efficiency.

As well as this in remote locations it may be expensive to be connected to the existing network of power lines due to the length of power lines needed to establish the connection. Stations to log data and the like in remote locations need power and are often run using generators. However these systems may need constant refueling and/or maintenance increasing the cost of running the stations. There is a need for a power supply system that uses sustainable generation and that produces little or no pollution.

SUMMARY OF INVENTION

In broad terms in one aspect the invention comprises a power supply system arranged to produce electrical power including; at least one battery arranged to supply power to an inverter, an inverter arranged to receive power from the battery(s) and produce output power calibrated to a predetermined level, and a charger arranged to receive a proportion of power from the inverter and provide power to the battery or battery bank.

The power generator may further include a power supply such as a solar panel or a thermal panel arranged to supply further power to the battery(s).

Preferably when the power generator includes a power supply it also includes a regulator arranged to regulate the voltage and current of power supplied to the battery or battery bank and also arranged to dump power when the battery(s) is charged to the appropriate level.

The inverter may be arranged to supply either single phase AC, three phase AC or DC power.

Preferably the battery or battery bank produces 12 VDC, 48 VDC or 96 VDC output. However batteries that produce other output voltages may be used if required.

Preferably the inverter is arranged to limit the output load to about 70% of the load capacity. Preferably the charging unit is arranged to measure the level of charge on the battery(s) and supply power to the battery(s) as required to maintain the battery(s) at a predetermined level.

BRIEF DESCRIPTION OF DRAWINGS

Preferred form systems and apparatus of the invention are further described with reference to the accompanying figures by way of example only and without intending to be limiting, wherein;

Figure 1 is a diagram of a first embodiment of power generator of the invention, and

Figure 2 is a diagram of a second embodiment of power generator of the invention including a power supply.

DETAILED DESCRIPTION OF PREFERRED FORMS

Figure 1 shows on embodiment of power generator of the invention. The power generator includes battery or battery bank 1, inverter 2 and charger 3. The battery or battery bank supplies power to the inverter 2. Inverter 2 then converts the current and voltage supplied by the battery or battery bank 1 into the current and voltage required to power the load. Some of the power output of the inverter is fed to charger 3. The charger maintains the float level of battery or battery bank 1 using the power supplied by inverter 2.

In one embodiment the inverter has a 12 VDC input and produces and output of 240 VAC with current between 5A and 35A as required. The output level is mains power so that appliances may be plugged directly into the generator. The load may be calibrated to the requirements of the user of the power generator and must not be exceeded. If the load is exceeded the power generator will run flat. In preferred embodiments the inverter includes a shut down or power interrupt means that prevents the output load from being exceeded. The inverter may also include a display screen that displays the current output level. The inverter may also include function keys such as an on/off switch and keys that allow a user to set the level of load that the inverter will power. The display screen may be an LCD screen or any other suitable screen. The inverter is chosen first by determining the user load requirements and then the charger load requirements. From these two measures the total load required from the inverter is assessed and an inverter capable of producing the required load is used. The total load required from the inverter is ideally less than about 70% of the capacity of the inverter. Of this amount ideally the load available for the user is less than 50% of the capacity of the inverter. The difference between the load available to the user and the total load is the load available to the charger to charge the battery(s).

In some embodiments a regulator may be included between battery bank 1 and inverter 2. This regulator takes power from battery bank 1 and transforms it to a suitable input voltage and current for inverter 2. The regulator is not required if the output of battery bank 1 falls within the range of allowed inputs for inverter 2.

The battery or battery bank may be arranged to produce any suitable voltage for the inverter. In general the inverter will be chosen first and capable of putting out a certain amount of power and the battery(s) will be chosen to supply the maximum input required by the inverter. Common values for the battery or battery bank include 12 VDC, 48 VDC and 96 VDC but these battery power values should not be seen as limiting. The battery(s) may further include a sensor arranged to request charge from the charging unit if the sensor detects that the charge on the battery(s) is below a predetermined value. In this way the battery sensor ensures that the charge on the battery(s) does not fall too low and that the battery(s) does not run flat.

If more than one battery or battery bank is used then ideally the charging unit is arranged to charge a first battery or battery bank as a second battery or battery bank discharges into the inverter. Once the second battery or battery bank is fully discharged the battery or battery bank controller or the charger switches the battery receiving the charge so that the second battery or battery bank is charged and the first battery or battery bank begins to discharge into the inverter. A third battery or battery bank may be used between the other batteries or battery banks and the inverter. If a third battery or battery bank is used in this way it receives charge from the other batteries or battery banks and discharges into the inverter. The battery banks may be part of a single battery bank unit.

The charging unit takes its input from the output of the inverter and sends charge to the battery(s) as required. The charging unit operates at an agreed frequency with the battery(s) and ensures that the frequency is synchronised with the battery(s). When the charging unit senses that the charge level on the battery(s) is too low or when the charging unit receives a request for more charge from the battery(s) then charge is supplied to the battery(s) to bring the battery(s) charge level up to within a predetermined range. When the battery(s) does not need charging the charging unit my wait in an inoperative mode until either the battery(s) requests further charge or the charger senses that the battery(s) require further charge.

- The power generator may also include diodes 4 between the battery(s) and the inverter and between the charger and the battery(s). The diodes are used to ensure that the components of the power generator are connected up correctly so that the current flows in the correct direction and to prevent major damage occurring to the components if they are connected up incorrectly.

Figure 2 shows a second embodiment of power generator of the invention. This second power generator includes a battery(s) 1 , inverter 2, charger 3, regulator 5 and power supply 6. The battery(s), inverter and charger are arranged to operate in the same way as described with reference to Figure 1. Power supply 6 is included as part of the power generator for instances when the maximum load allowed is run continuously and the generator is unable to maintain the balance in the battery(s). Power supply 6 can then be used to supply extra power to the battery(s) as required.

Regulator 5 is used with power supply 6 to regulate the power from power supply 6 and either supply power to the battery(s) or dump excess power. The regulator may convert the power from power supply 6 into the voltage and current required for the battery(s). The regulator may be further arranged to receive a signal from the battery(s) when the charge on the battery(s) falls below a predetermined level and the charger is not producing enough power to recharge the battery(s) and following that signal provide power to the battery(s). Alternatively the regulator may be arranged to sense the charge on the battery(s) and provide power to the battery(s) if the charge sensed by the regulator is below a predetermined level. If no power is required by the battery(s) and the regulator is receiving power from power supply 6 then the regulator is arranged to dump the excess power through lines 7. Lines 7 lead to a power dump device. The power dump device may cycle dumped power back to the regulator or through the power supply.

Power supply 6 may be a solar panel or a thermal panel or any other suitable power supply device. If the power supply is a thermal panel in one embodiment the power supply may be provided with heat from inverter 2. If the power supply is a solar panel in one embodiment the power supply may be supplied light from at least one bulb powered by inverter 2.

In a further embodiment the charger 3 is attached to regulator 5 instead of battery bank 1. In this embodiment the output of the regulator is the only input to battery bank 1. One advantage of connecting the charger to the regulator is that the regulator can control the charging of the battery bank and pass charge to the battery bank from the power supply or charger as required. The foregoing describes the invention including a preferred form thereof. Alterations and modifications as will be obvious to those skilled in the art are intended to be incorporated within the scope hereof.

Claims

WHAT WE CLAIM IS:

1. A power supply system arranged to provide electrical power, including: at least one battery, an inverter connected to the battery(s) and arranged to deliver output power up to a predetermined level to a load, and a charger arranged to also receive a proportion of the output power of the inverter and provide charging power to the battery(s).

2. A power supply system according to claim 1 including a further power source arranged to supply power directly or indirectly to the battery(s).

3. A power supply according to claim 2 wherein said further power source comprises an associated solar panel or thermal panel.

4. A power supply according to claim 2 or claim 3 including a regulator arranged to regulate the voltage and current of power supplied to the battery(s) from said further power source.

5. A power supply according to any one of claims 1 to 4 wherein the inverter is arranged to supply either single phase AC, three phase AC or DC power.

6. A power supply according to any one of claims 1 to 5 which is arranged so that the output load on the inverter comprising the output load on the power supply and the charger together, is limited to less than about 70% of the output load capacity of the inverter.

7. A power supply according to claim 6 which is arranged so that the output load on the power supply is limited to less than about 50% of the output load capacity of the inverter.

8. A power supply according to any one of claims 1 to 7 wherein the charger is arranged to monitor the charge state of the battery(s) and supply charge to the battery(s) as required to maintain charge state of the battery(s) at a predetermined level.

9. A power supply system arranged to provide electrical power, including: at least one battery, an inverter connected to the battery(s) and arranged to deliver output power up to a predetermined level to a load and arranged so that the output load on the inverter is limited to less than the output load capacity of the inverter, a charger arranged to monitor the charge state of the battery(s) and also receive a proportion of the output power of the inverter and provide charging power to the battery(s) when required, and a further power source also arranged to supply power directly or indirectly to the battery(s) when the output load on the power supply is such that the charger is otherwise unable to maintain the charge state of the battery(s) at or towards a predetermined level.