Method for controlling the power of a system, and device for controlling the power of a system

Abstract

A method for controlling the power of a system, and a device for controlling the power of a system, the system having an electric energy source, electric consumers, an energy storage, an inverter, and a charge controller, the system being connected via an interconnected power sensor to the in particular public AC electric power supply, and the power sensor may be used for ascertaining the power withdrawn by the system from the in particular public AC electric power supply, or for ascertaining a corresponding quantity, such as the active power withdrawn from the in particular public AC electric power supply, the sensor signal being transmitted to a controller which regulates the power withdrawn from the in particular public AC electric power supply toward zero by appropriate actuation of the inverter and the charge controller.

Claims

1. A method for controlling a power of a system that includes an electric energy source, an electric consumer, an energy storage, an inverter, and a charge controller, the method comprising: connecting the system via an interconnected power sensor to a public AC electric power supply, the interconnected power sensor capable of one of: ascertaining a power withdrawn by the system from the public AC electric power supply, and ascertaining a quantity corresponding to the withdrawn power; and transmitting a sensor signal to a controller that regulates a power supply from the public AC electric power supply toward zero by appropriate actuation of the inverter and the charge controller; wherein if a photovoltaically generated electric power exceeds a power consumed by the electric consumer: the controller controls the charge controller in such a way that excess power is routed to the energy storage and only power that is in excess thereof is injected into the public AC electric power supply; and the inverter is at least one of switched into a quiescent state, deactivated, and switched off by the controller; and wherein if the photovoltaically generated electric power drops below the power consumed by the electric consumer: the controller controls the inverter in such a way that the electric consumer is supplied with power from the energy storage and only power required by the electric consumer in excess of the photovoltaically generated electric power and the power supplied from the energy storage is supplied by the public AC electric power supply; and the controller at least one of switches the charge controller into a quiescent state, deactivates the charge controller, and switches the charge controller off.

2. The method as recited in claim 1, wherein the corresponding quantity includes an active power withdrawn from the public AC electric power supply.

3. The method as recited in claim 1, wherein the electric energy source includes one of a photovoltaic system and a regenerative energy source.

4. The method as recited in claim 3, wherein the regenerative energy source includes wind power.

5. The method as recited in claim 1, wherein the inverter and the charge controller are activated alternatively.

6. The method as recited in claim 1, wherein a hysteresis is taken into account when actuating at least one of the charge controller and the inverter.

7. The method as recited in claim 1, wherein a signal electronics system of the inverter carries out a charge control for the energy storage.

8. The method as recited in claim 7, wherein the signal electronics system is situated in a housing of the inverter.

9. The method as recited in claim 1, further comprising: providing a sensor for detecting a temperature of the energy storage; and supplying a sensor signal of the temperature detecting sensor to a signal electronics system of the inverter, so that a temperature-dependent charge control is able to be implemented for the energy storage.

10. A device for controlling a power of a system that includes an electric energy source, an electric consumer, an energy storage, an inverter, and a charge controller, the device comprising: a power sensor interconnected between the system and a public AC electric power supply, the power sensor one of: ascertaining a power withdrawn by the system from the public AC electric power supply, and ascertaining a quantity corresponding to the withdrawn power, wherein a sensor signal from the power sensor is supplied to a controller which controls the power withdrawn from the public AC electric power supply towards zero by appropriate control of at least one of the inverter and the charge controller via a control path; wherein if a photovoltaically generated electric power exceeds a power consumed by the electric consumer: the controller controls the charge controller in such a way that excess power is routed to the energy storage and only power that is in excess thereof is injected into the public AC electric power supply; and the inverter is at least one of switched into a quiescent state, deactivated, and switched off by the controller; and wherein if the photovoltaically generated electric power drops below the power consumed by the electric consumer: the controller controls the inverter in such a way that the electric consumer is supplied with power from the energy storage and only power required by the electric consumer in excess of the photovoltaically generated electric power and the power supplied from the energy storage is supplied by the public AC electric power supply; and the controller at least one of switches the charge controller into a quiescent state, deactivates the charge controller, and switches the charge controller off.

11. The device as recited in claim 10, wherein the corresponding quantity includes an active power withdrawn from the public AC electric power supply.

12. The device as recited in claim 10, wherein the controller includes a housing disposed in a signal electronics system.

13. The device as recited in claim 10, wherein the control path from a direction of the controller has a selector switch, so that either the inverter or the charge controller is activated.

14. The device as recited in claim 13, wherein a hysteresis is provided during the activation.

15. The device as recited in claim 10, wherein a signal electronics system of the inverter is situated inside a housing of the inverter.

16. The device as recited in claim 10, further comprising: a sensor for detecting a temperature of the energy storage, wherein a sensor signal of the temperature detecting sensor is supplied to a signal electronics system of the inverter, so that a temperature-dependent charge control is able to be implemented for the energy storage.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The FIGURE illustrates a schematic structure of a system according to the present invention.

DETAILED DESCRIPTION

(2) Using a photovoltaic system 1, which in particular includes solar modules, a direct current is generated, the direct current being supplied to an inverter 2, which generates an alternating voltage. An input counter 3, which detects the electric energy made available, is situated at the output of inverter 2.

(3) Consumers 4, in particular a washing machine, a refrigerator, an electric automobile, are supplyable at the output of the inverter. Inverter 2 synchronizes the voltage it has generated to the voltage of the in particular public AC electric power supply 10.

(4) A four-quadrant energy counter 9, especially an active power sensor, is situated between the in particular public AC electric power supply 10 and the output of inverter 2 and/or input counter 3. Utilizing this four-quadrant energy counter 9, it is therefore detectable whether an energy withdrawal from the in particular public AC electric power supply 10 or an energy supply to the in particular public AC electric power supply 10 is taking place. In other words, the direction of the energy flow from the system into the in particular public AC electric power supply 10 or from the in particular public AC electric power supply 10 into the system is detected.

(5) Depending on the detected active power and/or the direction of the energy flow, a switch S is actuated, which activates either a charge controller 5, especially including a rectifier, or an inverter 6.

(6) Charge controller 5 supplies energy storage 7 with current injected by inverter 2 in order to charge it, provided it is activated.

(7) When inverter 6 is activated, energy storage 7 is discharged by supplying the DC-side terminal of inverter 6 from there. At its AC voltage output, inverter 6 supplies the system, i.e., especially the consumers, with an alternating voltage. This makes it possible to supply the consumers from energy storage 7 via inverter 6, and the withdrawal from the in particular public AC electric energy supply 10 is kept to a minimum.

(8) That is to say, the power, especially the effective power, withdrawn by the system from the in particular public supply 10 is detected with the aid of the four-quadrant energy counter 9, in particular the active power sensor; it is supplied as actual value to a controller, which regulates this actual value to the setpoint value of zero by appropriate actuation of control 8 of switch S. In this manner as little energy as possible is withdrawn from the in particular public AC electric energy supply 10 and, given high solar radiation, the excess energy is supplied predominantly into energy storage 7. Only when energy storage 7 has been charged and if excess photovoltaically generated energy is still available, will this energy be injected into the in particular public AC electric power supply 10.

(9) If no photovoltaically generated power is available or barely any is available, power from energy storage 7 is supplied to consumers of the system and as little as possible from the in particular public AC electric power supply 10. Only when energy storage 7 is depleted and inverter 6 is unable to supply sufficient power will power be routed to the consumers of the system from the in particular public AC electric power supply 10.

(10) In one further exemplary embodiment according to the present invention, the charge controller has an inverter which is actuated in a pulse-width modulated manner, the inverter's DC-side terminal being supplied by a rectifier of the charge controller. The AC-voltage-side output of the inverter is rectified by a further rectifier and charge voltage is thus provided to the energy storage. This makes it possible to detect the charge current and the charge voltage with the aid of the charge controller using its respective sensors, and energy storage 7 is charged to the maximum charge power.

LIST OF REFERENCE NUMERALS

(11) 1 photovoltaic system, in particular solar modules

(12) 2 inverter

(13) 3 input counter

(14) 4 consumers, in particular washing machine, refrigerator, electric automobile

(15) 5 charge controller, in particular including a rectifier

(16) 6 inverter

(17) 7 energy storage

(18) 8 control

(19) 9 four-quadrant energy counter, in particular active power sensor

(20) 10 in particular public AC electric power supply

(21) S switch