For bio-electrically generating electric power from organic ingredients of a waste water flowing in a flow direction, an anode is immersed in the waste water in a first spatial area, and oxygen is supplied to a cathode which is electrically connected to the anode and arranged in a second spatial area delimited from the first spatial area by means of a proton-permeable membrane. A voltage between the anode and the cathode is increased by a DC/DC converter located at the anode and the cathode, and a further voltage between a further anode in said or a further first spatial area and a further cathode in said or a further second spatial area is increased by a further DC/DC converter located at the further anode and the further cathode. A DC voltage link is charged with the DC/DC converter and the further DC/DC converter connected in parallel to the DC voltage link.

A power supply device for supplying power to a load by combining a secondary battery and a capacitor includes a switching element which switches the supply of power to the load from the capacitor, a DC-DC converter which enables a voltage of the capacitor to be stepped up and supplied to the load and a control unit which enables power to be supplied to the load by pulse-controlling the switching element, controlling the DC-DC converter to output a pulse current alternately with the switching element and combining the alternately output pulse currents if the voltage of the capacitor drops below a minimum voltage capable of driving the load.

A power supply device for supplying power to a load by combining a secondary battery and a capacitor includes a switching element which switches the supply of power to the load from the capacitor, a DC-DC converter which enables a voltage of the capacitor to be stepped up and supplied to the load and a control unit which enables power to be supplied to the load by pulse-controlling the switching element, controlling the DC-DC converter to output a pulse current alternately with the switching element and combining the alternately output pulse currents if the voltage of the capacitor drops below a minimum voltage capable of driving the load.

A converter control arrangement (18) for regulating the output current of a dc source power converter (16) comprises a current regulator (20) for regulating the output current based on a comparison of an output current value (I.sub.out) of the dc source power converter (16) with a desired target current value (I.sub.tgt). When the output voltage value (V.sub.out) of the dc source power converter (16) is within a normal operating voltage range between minimum and maximum voltage values (V.sub.min, V.sub.max) defined with respect to a voltage reference value (V.sub.ref) of the dc source power converter (16), the converter control arrangement (18) controls the target current value (I.sub.tgt) so that it is equal to a desired reference current value (I.sub.ref). When the output voltage value (V.sub.out) is outside the normal operating voltage range, which typically indicates a fault condition, the converter control arrangement (18) modulates the reference current value (I.sub.ref) to provide a target current value (I.sub.tgt) that is less than the reference current value (I.sub.ref).

A converter control arrangement (18) for regulating the output current of a dc source power converter (16) comprises a current regulator (20) for regulating the output current based on a comparison of an output current value (I.sub.out) of the dc source power converter (16) with a desired target current value (I.sub.tgt). When the output voltage value (V.sub.out) of the dc source power converter (16) is within a normal operating voltage range between minimum and maximum voltage values (V.sub.min, V.sub.max) defined with respect to a voltage reference value (V.sub.ref) of the dc source power converter (16), the converter control arrangement (18) controls the target current value (I.sub.tgt) so that it is equal to a desired reference current value (I.sub.ref). When the output voltage value (V.sub.out) is outside the normal operating voltage range, which typically indicates a fault condition, the converter control arrangement (18) modulates the reference current value (I.sub.ref) to provide a target current value (I.sub.tgt) that is less than the reference current value (I.sub.ref).

In order to protect reverse currents, several strings of a photovoltaic generator, which are connected in small groups respectively via a DC/DC-converter, parallel to a common DC voltage intermediate circuit, the current which flows over each of the DC/DC-converter is detected and if a reverse current is detected flowing through one of the DC/DC converters, the converter is stopped by controlling the DC/DC-converter.

In order to protect reverse currents, several strings of a photovoltaic generator, which are connected in small groups respectively via a DC/DC-converter, parallel to a common DC voltage intermediate circuit, the current which flows over each of the DC/DC-converter is detected and if a reverse current is detected flowing through one of the DC/DC converters, the converter is stopped by controlling the DC/DC-converter.

To provide a bandgap reference circuit capable of shortening a start time at power-on in a circuit lowered in power consumption. There is provided a bandgap reference circuit using an op amplifier to generate a reference voltage, which is equipped with a first current source connected between a power supply terminal and an operating current input terminal of the op amplifier, a second current source having one end connected to the power supply terminal, and a switch connected between the other end of the second current source and the operating current input terminal of the op amplifier, and in which a switch is turned on at power-on and turned off after starting of the reference voltage.

In a control apparatus for a power conversion apparatus, a spectrum changing unit changes a spectrum of at least one of bus harmonic components and switch harmonic components so as to meet at least one of a separation condition and a reduction condition. The bus harmonic components are harmonic components superimposed on a voltage of the bus in accompaniment with on-off operations of switches configuring at least one power conversion apparatuses. The switch harmonic components are harmonic components included in a switching pattern of switches configuring the remaining at least one power conversion apparatus. The separation condition is that the frequencies of both harmonic components are separated by a predetermined value or more. The reduction condition is that an amplitude of at least one harmonic component is reduced when the difference between the frequencies of both harmonic components is less than the predetermined value.

In a control apparatus for a power conversion apparatus, a spectrum changing unit changes a spectrum of at least one of bus harmonic components and switch harmonic components so as to meet at least one of a separation condition and a reduction condition. The bus harmonic components are harmonic components superimposed on a voltage of the bus in accompaniment with on-off operations of switches configuring at least one power conversion apparatuses. The switch harmonic components are harmonic components included in a switching pattern of switches configuring the remaining at least one power conversion apparatus. The separation condition is that the frequencies of both harmonic components are separated by a predetermined value or more. The reduction condition is that an amplitude of at least one harmonic component is reduced when the difference between the frequencies of both harmonic components is less than the predetermined value.