A power supply device may include a connector configured to electrically couple the power supply device to a conductor of the underground power lines; a voltage divider configured to receive an input voltage from the conductor, the voltage divider comprising a capacitor and divider voltage control electronics in series with the capacitor; and, a surge resistor in series with the capacitor and configured to provide impulse protection from surge events. The divider voltage control electronics may be configured to regulate an output voltage of the voltage divider to support variable loads on the voltage divider.

A charging device includes a passive auxiliary circuit and a rectifier which is connected downstream of the auxiliary circuit. The passive auxiliary circuit includes input nodes and output nodes. Between the input node and the output nodes, two impedances are connected. Here, an imaginary component of the first impedance has a positive non-zero value and an imaginary component of the second impedance a negative non-zero value or vice versa.

A charging device includes a passive auxiliary circuit and a rectifier which is connected downstream of the auxiliary circuit. The passive auxiliary circuit includes input nodes and output nodes. Between the input node and the output nodes, two impedances are connected. Here, an imaginary component of the first impedance has a positive non-zero value and an imaginary component of the second impedance a negative non-zero value or vice versa.

The brake driving control circuit, which controls an electromagnetic brake that releases the brake by applying a current, is provided with: a first rectifying element provided between a first power supply of a first circuit voltage and one terminal of the electromagnetic brake; a cut-off switch inserted into a line through which the first power supply supplies power; a first switching element provided between the other terminal of the electromagnetic brake and a ground point; and a second switching element and a second rectifying element provided in series between a second power supply of a second circuit voltage, which is different from the first circuit voltage, and the one terminal of the electromagnetic brake.

The brake driving control circuit, which controls an electromagnetic brake that releases the brake by applying a current, is provided with: a first rectifying element provided between a first power supply of a first circuit voltage and one terminal of the electromagnetic brake; a cut-off switch inserted into a line through which the first power supply supplies power; a first switching element provided between the other terminal of the electromagnetic brake and a ground point; and a second switching element and a second rectifying element provided in series between a second power supply of a second circuit voltage, which is different from the first circuit voltage, and the one terminal of the electromagnetic brake.

An apparatus having an AC rectifier configured to generate one or more rectified signals from an alternating current (AC) signal, bus having a positive line and a negative line, parallel converter connected between the positive line and the negative line, and bulk capacitor coupled to the parallel converter. The bus is connected to the AC rectifier to receive a first of the rectified signals between the positive line and the negative line. The apparatus has a controller configured to operate the parallel converter in a first mode in which energy from a second of the rectified signals from the AC rectifier is stored in the bulk capacitor and a second mode in which the energy stored in the bulk capacitor is discharged to the bus to increase a voltage on the bus during at least an initial portion of the second mode.

An apparatus having an AC rectifier configured to generate one or more rectified signals from an alternating current (AC) signal, bus having a positive line and a negative line, parallel converter connected between the positive line and the negative line, and bulk capacitor coupled to the parallel converter. The bus is connected to the AC rectifier to receive a first of the rectified signals between the positive line and the negative line. The apparatus has a controller configured to operate the parallel converter in a first mode in which energy from a second of the rectified signals from the AC rectifier is stored in the bulk capacitor and a second mode in which the energy stored in the bulk capacitor is discharged to the bus to increase a voltage on the bus during at least an initial portion of the second mode.

A method of powering a controller using an intermediate device with power from an environmental system may include receiving current from a power wire from the environmental system; passing the current from the power wire to a second command wire from the controller; monitoring the current flowing between the power wire and the second command wire while the current is below a threshold indicative of an amount of current used to power the controller from the environmental system; detecting when the current flowing between the power wire and the second command wire exceeds the threshold indicating that the controller is sending a command to the environmental system to perform the function; and sending a command to environmental system using a first command wire from the environmental system after detecting that the current exceeds the threshold.

Power isolators for providing electrical isolation between an input port and an output port that exhibit low electromagnetic interference (EMI) are described. The low EMI may be achieved by, for example, canceling out a common mode current across a transformer in the power isolator that may be converted into EMI. The power isolator may include at least one oscillator circuit that is configured to apply a first signal to a first transformer and a second, different signal to a second transformer. The first and second signals may be configured such that the common mode current generated in each of the first and second transformers has an opposite direction. Thus, the common mode currents in the first and second transformers may at least partially cancel out. As a result, the EMI exhibited by the power isolator may be reduced.

Power isolators for providing electrical isolation between an input port and an output port that exhibit low electromagnetic interference (EMI) are described. The low EMI may be achieved by, for example, canceling out a common mode current across a transformer in the power isolator that may be converted into EMI. The power isolator may include at least one oscillator circuit that is configured to apply a first signal to a first transformer and a second, different signal to a second transformer. The first and second signals may be configured such that the common mode current generated in each of the first and second transformers has an opposite direction. Thus, the common mode currents in the first and second transformers may at least partially cancel out. As a result, the EMI exhibited by the power isolator may be reduced.