Power management apparatus for energy harvesting

A method of controlling a power management apparatus, the power management apparatus comprising an inductor connection for connecting to an inductor, a first energy harvesting input channel for connecting to a first electrical energy harvesting source, a first energy storage element output for connecting to an energy storage element and a switching circuit, the first energy harvesting input channel comprising a first input line and a second input line, the method comprising:

• operating the switching circuit to transfer energy between the first energy harvesting input channel and the first energy storage element connection by a sequence of energy transfer cycles, each of the energy transfer cycles comprising:
• an energise phase in which energy is transferred from the first energy harvesting input channel to the inductor connection for an energise time (tE) to transfer energy to the inductor and;
• a de-energise phase in which energy is transferred from the inductor connection to the first energy storage element connection for a de-energise time (tD),
• wherein the first energy harvesting input channel is allocated a plurality of the energy transfer cycles, with a harvesting cycle period (tP) between start times of successive energy transfer cycles;
• wherein the first energy harvesting input channel is capable of receiving an electrical signal from the set of an AC electrical signal and a DC electrical signal and the method comprises determining a type of an electrical signal received at the first energy harvesting input channel, where the type is one of an AC electrical signal and a DC electrical signal, and determining an energise time (tE) and a harvesting cycle period (tP) for the switching circuit based on the determined type, and
• wherein the method comprises determining a type of an electrical signal received at the first energy harvesting input channel by detecting a relative polarity of a signal on the first input line and a signal on the second input line.

A computer program product comprising a non-transitory computer-readable storage medium having instructions stored on the medium which, when the instructions are executed by a computer, cause the computer to carry out a method of

• operating a switching circuit to transfer energy between a first energy harvesting input channel and a first energy storage element connection by a sequence of energy transfer cycles, each of the energy transfer cycles comprising:
• an energise phase in which energy is transferred from the first energy harvesting input channel to an inductor connection for an energise time (tE) to transfer energy to the inductor and;
• a de-energise phase in which energy is transferred from the inductor connection to a first energy storage element connection for a de-energise time (tD),
• wherein the first energy harvesting input channel is allocated a plurality of the energy transfer cycles, with a harvesting cycle period (tP) between start times of successive energy transfer cycles;
• determining a type of an electrical signal received at the first energy harvesting input channel, where the type is one of an AC electrical signal and a DC electrical signal, and determining an energise time (tE) and a harvesting cycle period (tP) for the switching circuit based on the determined type, and
• determining a type of an electrical signal received at the first energy harvesting input channel by detecting a relative polarity of a signal on a first input line of the first energy harvesting input channel and a signal on a second input line of the first energy harvesting input channel.