Co-generated power supply system

Abstract

In a co-generated power supply system for performing dispersed power supply to a load, a wind turbine generator, a solar cell and a fuel cell whose rated voltages are made equal to a rated voltage of a storage battery are used as DC power sources. These DC power sources, a commercial AC power source and the load are connected to each other via a bi-directional electronic transformer. Thus, the co-generated power supply system, in which the electric power of a natural energy system having many fluctuation factors is combined with stable electric power such as a load leveling battery or a fuel cell, allows the stable electric power to be supplied to the load via the electronic transformer commonly, thereby reducing the cost and enhancing the performance of the entire system.

Description

[0001]This application is a divisional application of application Ser. No. 10 / 630,692, filed Jul. 31, 2003.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to a novel co-generated power supply system, which is useful for co-generated power supply of a combination of natural energy and stable energy such as a fuel cell and power storage energy during the nighttime and midnight, and especially, which can efficiently supply electric power to a load by connecting a plurality of AC and DC energy sources to each other via an electronic transformer, a diode and an OR circuit.[0004]2. Description of the Related Art[0005]As a typical example of clean energy, the solar cell has been prevalant. Furthermore, the wind turbine generator has been introduced in local regions. Since in these types of natural energy, the duration of sunshine, the operation rate of a windmill or generated electric power fluctuates at all times due to variations in weather o...

AI Technical Summary

Benefits of technology

[0014]In view of the foregoing, it is the main object of the present invention to provide a novel co-generated power supply system, in which electric power of a natural energy system having many fluctuation factors is combined with stable electric power such as a battery storing midnight electric power or a fuel cell, so that the stable electric power is supplied to a load via an electronic transformer commonly used at a usage rate of almost 100%, thus reducing the cost and enhancing the performance of the entire system, so as to spread and make more prevalent the co-generated power supply and save the energy.

[0015]According to the novel co-generated power supply system of the present invention, in the case where the electric power is supplied directly to the load from both AC and DC sources as illustrated in FIG. 3, the efficiency can be enhanced by the amount of removed efficiency η1 of the inverter in comparison with the prior art illustrated in FIG. 1. Furthermore, although it might be necessary to insert a device used as both insulator and transformer between the commercial AC power source and the co-generated power equipment for the reason of protection, the efficiency η1 of the DC-AC inverter of several kilowatts or less including an insulating function is about 90% and the efficiency η1′ of the electronic transformer of the same capacity is about 94% to 95%, resulting in η1<η1′. Thus, the system of the present invention can still achieve better efficiency.

Problems solved by technology

Since in these types of natural energy, the duration of sunshine, the operation rate of a windmill or generated electric power fluctuates at all times due to variations in weather or meteorological situations, it is difficult to stably supply electric power.

In contrast, a dimmer, a space heating appliance and an automatic rice cooker of a thyristor phase control system cannot be used with DC under present circumstances.

As a consequence, there has arisen an immediate inconvenience that the appliance only for AC and the household electric appliance for both of AC and DC must be used with separate indoor wiring systems (i.e., receptacles) independent of each other.

However, the DC power generation energy always is reversely converted into the commercial AC through an inverter in the conventional system, and then, is converted into the DC again within an actual load, and further, is converted into a high frequency inverter or a variable frequency AC power, so as to drive an electric motor or a compressor, thereby increasing a conversion loss.

If control equipment such as an inverter is provided for each electric power of the energy generating source of a low operating rate in the above-described manner, the cost of the entire system is increased, thereby leading to one factor of inhibition of popular use.

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