Apparatus and method for electrically killing plants

Abstract

An electrical energy processing unit of apparatus to kill a plant or at least attenuate plant growth, the electrical energy processing unit comprising: a converter configured to receive unprocessed electrical energy from an electrical energy source, to convert the unprocessed electrical energy to processed electrical energy and to output said processed electrical energy to an applicator unit; a control circuit operable to control the converter to convert the unprocessed electrical energy to the processed electrical energy, wherein the processed electrical energy comprises a waveform with a frequency of at least 18 kHz and with a peak voltage of at least 1 kV.

1 . An electrical energy processing unit of an apparatus to kill a plant or at least attenuate plant growth, the electrical energy processing unit comprising:
 a converter configured to receive unprocessed electrical energy from an electrical energy source, to convert the unprocessed electrical energy to processed electrical energy, and to transmit said processed electrical energy between an applicator electrode of an applicator unit and an earth electrode of an earth unit,   wherein the processed electrical energy comprises a waveform with a frequency of at least 18 kHz and with a peak voltage of at least 1 kV.   
     
     
         2 . The electrical energy processing unit according to  claim 1 , wherein the electrical energy processing unit is configured to produce processed electrical energy that comprises a current of at least 10 mA rms and/or a power of at least 5 W. 
     
     
         3 . The electrical energy processing unit according to  claim 1 , wherein the electrical energy processing unit is configured to produce processed electrical energy that is operable to kill a plant or at least partially attenuating plant growth with a treatment time of at least 10 milliseconds. 
     
     
         4 . The electrical energy processing unit according to  claim 1 , further comprising a control circuit operable to control the converter to convert the unprocessed electrical energy to the processed electrical energy, wherein the control circuit is configured to control an aspect of the processed electrical energy comprising one or a combination of the: voltage; current; power, the said aspect controlled to be:
 maintained substantially at a predetermined value; or   below or above a predetermined value; or   
     
     
         5 . The electrical energy processing unit according to  claim 4 , wherein the control circuit is configured to control the said aspect of the processed electrical energy by controlling an amplitude and/or duty cycle or period of the processed electrical energy. 
     
     
         6 . The electrical energy processing unit according to  claim 1 , further comprising a control circuit operable to control the converter to convert the unprocessed electrical energy to the processed electrical energy, wherein the control circuit is configured to control the voltage of the processed electrical energy, and the control circuit is configured to:
 in response to a decreasing voltage of the processed electrical energy increase the amplitude and/or duty cycle or period thereof; and/or   in response to an increasing voltage of the processed electrical energy decrease the amplitude and/or duty cycle or period thereof.   
     
     
         7 . The electrical energy processing unit according to  claim 1 , further comprising a control circuit operable to control the converter to convert the unprocessed electrical energy to the processed electrical energy, wherein the control circuit is configured to control the current or power of the processed electrical energy, and the control circuit is configured to:
 in response to a decreasing current of the processed electrical energy increase the amplitude and/or duty cycle or period thereof; and/or   in response to an increasing current of the processed electrical energy decrease the amplitude and/or duty cycle or period thereof.   
     
     
         8 . The electrical energy processing unit according to  claim 1 , further comprising a control circuit operable to control the converter to convert the unprocessed electrical energy to the processed electrical energy, wherein the converter comprises at least one sensor, the control circuit being operatively connected to the sensor to receive therefrom a converter feedback signal, the converter feedback signal comprising information to monitor an aspect of the processed electric energy, wherein the control circuit is configured to provide closed-loop control of the said aspect of the processed electrical energy using the said converter feedback signal. 
     
     
         9 . An apparatus to electrically kill a plant or at least attenuate plant growth, the apparatus comprising:
 the electrical energy processing unit according to  claim 1 ; and   at least one applicator unit to apply the processed electrical energy to a plant, the applicator unit comprising an applicator electrode, the applicator electrode comprising an electrically conductive material, which is connected to the converter of the electrical energy processing unit to receive therefrom the processed electrical energy.   
     
     
         10 . The apparatus according to  claim 9 , wherein the applicator electrode is configured for direct transmission of the processed electrical energy to a plant. 
     
     
         11 . The apparatus according to  claim 9 , further comprising an earth unit, the earth unit comprising an earth electrode of electrically conductive material, which is connected to the converter to receive the processed electrical energy transmitted from the applicator unit through a load comprising a plant. 
     
     
         12 . The apparatus according to  claim 11 , wherein the earth electrode comprises a substantially flat surface configured to receive the processed electrical energy when resting on a surface of the ground. 
     
     
         13 . The apparatus according to  claim 9 , further comprising an energy source connected to the electrical energy processing unit or at least a portion of an electrical interface for connecting an electrical energy source to the electrical energy processing unit. 
     
     
         14 . A method to electrically kill a plant or at least attenuate plant growth comprising:
 supplying processed electrical energy to a plant using the apparatus according to  claim 9 ,   wherein the processed electrical energy comprises a waveform with a frequency of at least 18 kHz and with a peak voltage of at least 1 kV.   
     
     
         15 . The method according to of  claim 14 , wherein the earth electrode of the apparatus comprises a substantially flat surface configured to receive the processed electrical energy when resting on a surface of the ground, and wherein the method further comprises using the apparatus to electrically kill or at least attenuate growth of a first plant located at a first location and a second plant located at a second location by: moving the earth electrode of the earth unit along the ground whilst maintaining electrical continuity between the earth unit and the ground. 
     
     
         16 . A use of an electrical energy processing unit for treating a plant to kill or at least attenuate growth thereof by applying a frequency of at least 18 kHz and with a peak voltage of at least 1 kV thereto. 
     
     
         17 . A computer program for a processor of a control circuit of an electrical energy processing unit according to  claim 1 , the computer program comprising program code to control the converter to generate processed electrical energy with a waveform that has a frequency of at least 18 kHz and with a peak voltage of at least 1 kV. 
     
     
         18 . A non-transitory computer readable medium comprising the computer program according to  claim 17 .