Abstract: The present disclosure relates to an uninterruptible power supply (UPS) for monitoring and prioritizing use of available power. The UPS has an electronic controller with a memory and a software control module. The UPS also has a battery, a rectifier for rectifying available AC power from a primary external AC power source to produce DC power, an inverter in communication with the rectifier for generating AC power from the DC power provided by the rectifier, and a DC/DC converter in communication with the rectifier for producing a DC charging current for use in charging the battery. The electronic controller and the software control module are configured to dynamically prioritize the use of available power from at least one of the primary AC power source and from the battery, to maintain adequate power to a load being supported by the UPS, as well as to charge the battery of the UPS when predetermined operating conditions are met.

Abstract: System and method for managing a cumulative DC offset in a magnetizable material. A primary driving AC voltage and a magnetic flux sensor. The flux sensor output is continuously received into memory while the flux sensor output for each phase half-cycle is processed to continuously compute and re-compute in real time a flux-second integral for each half-cycle. The two half-cycle flux-second integrals are compared to each other for a DC offset value and the offset value drives a slow loop DC compensation circuit to steer a PWM control.

Abstract: Described are a method for suppressing overshoot of an output voltage or output current, a charging device, and a medium. The method for suppressing the overshoot of the output voltage or output current includes the following. A loop in an open-loop state in a closed-loop control circuit is determined. A wave-sending control value output by the closed-loop control circuit at a present beat is obtained. The wave-sending control value output at the present beat is assigned to an open-loop output value at the present beat, where the open-loop output value is an output value of the loop in the open-loop state. An open-loop output value of a loop in the open-loop state at a next beat is calculated by using an assigned open-loop output value at the present beat.

Abstract: An apparatus for generating an output voltage including a microcontroller unit (MCU) configured to selectively generate a data modulating signal; and a voltage regulator configured to generate an output voltage modulated based on the data modulating signal. Another aspect relates to a method of generating an output voltage comprising selectively generating a data modulating signal; and bucking and boosting an output voltage based on the data modulating signal. An additional aspect relates to an apparatus for generating an output voltage comprising means to selectively generate a data modulating signal, and means for bucking and boosting an output voltage based on the data modulating signal.

Abstract: A charging system for an electric vehicle includes: a rechargeable energy storage device adapted to store electrical energy and to supply the stored electrical energy to at least one electric motor of the vehicle to propel the vehicle; a charger adapted to supply electrical energy to the energy storage device according to a selectable power rating of at least two power ratings to charge and/or recharge the energy storage device based on a selected one of power ratings; and a controller adapted to select one of the power ratings of the charger to set the charger to charge and/or recharge the energy storage device based on the selected one of the power ratings.

Abstract: A monitoring system and method for operation of energy storage system are provided, the system includes a collection module, configured to collect operation data of the energy storage system; a predictive module, configured to predict the operation data to obtain predictive data of future development trend of the energy storage system; a processing module, configured to process the operation data and the predictive data to obtain an operation state of battery packs in the energy storage system; a storage module, configured to store the operation data, the predictive data and the operation state of the battery packs; and an evaluation module, configured to evaluate an operation state of the energy storage system according to operation data, predictive data and the operation state of the battery packs. The energy storage system is monitored, and the operation state of the energy storage system is evaluated by combining with power grid dispatch instructions.

Abstract: A power delivery system may include an inductive power converter comprising a shared connection to a shared voltage from a battery, multiple inductive phases, each of the multiple inductive phases configured to generate a respective voltage from the shared voltage, multiple regulated voltage connections, and one or more switches configured and arranged to selectively assign at least one of the multiple inductive phases to a regulated voltage connection selected from the multiple regulated voltage connections.

Abstract: A controller for a voltage converter, such as a buck converter, includes: a switching regulator circuit having high side and low side switches; comparators configured to compare a voltage of an output circuit to reference voltages; and a control circuit coupled to the current comparators, configured to receive outputs from the comparators, and configured to generate a control signal for alternatingly switching the high side and low side switches off and on, such that the low side switch is off when the high side switch is on, and the high side switch is off when the low side switch is on, and wherein the control circuit includes a latching circuit configured to latch a signal corresponding to at least one of the outputs from the comparators. A method of operating a buck converter in connection with a fixed high-frequency automotive radar system, with reliable over-current detection, is also disclosed.

Abstract: In general, techniques are described that are directed to a device that includes a power storage device, an electrical load, and a first regulated power converter including components configured to generate, during a first time period and using electrical energy received from a power source external to the device, a first power signal to charge the power storage device. A second regulated power converter includes components configured to determine a charging current at which to charge the power storage device, determine a total amount of current flowing to the power storage device that includes current sourced by the second power converter less current sinked by the electrical load, and generate, during a second time period that is non-overlapping with the first time period, using electrical energy from the power source and based on determined the total amount of current, a second power signal to charge the power storage device.

Abstract: Examples described herein provide a method that includes determining whether a vehicle is operating in a first high voltage mode or a second high voltage mode. The method further includes, responsive to determining that the vehicle is operating in the first high voltage mode, providing electric power to an electric motor at a first high voltage and providing electric power to an auxiliary device at a second high voltage that is different than the first high voltage. The method further includes, responsive to determining that the vehicle is operating in the second high voltage mode, providing electric power to the electric motor at the second high voltage and providing electric power to the auxiliary device at the second high voltage.

Abstract: Systems and methods for controlling a plurality of DC/DC converters that are coupled to either a renewable energy source or an energy storage device. The system automatically detects the energy source coupled to the relevant DC/DC converter and operates accordingly. If the DC/DC converter is coupled to a renewable energy source (such as a PV panel), the system maximizes power extraction from the energy source. If the DC/DC converter is coupled to an energy storage device, the system performs charge/discharge functions for the attached energy storage device.

Abstract: A switching power supply device includes first to fourth switches sequentially connected in series, an inductor, a first capacitor whose first end is connected to a connection node of the first switch and the second switch and whose second end is connected to a connection node of the third switch, the fourth switch, and the inductor, a second capacitor whose first end is connected to a connection node of the second switch and the third switch, and a controller that controls switching on and off of the first to fourth switches. In at least one of a first pair configured with the first switch and the third switch and a second pair configured with the second switch and the fourth switch, the controller shifts a timing of switching from off to on between two switches.

Abstract: System and method for managing a cumulative DC offset in a magnetizable material. A primary driving AC voltage and a magnetic flux sensor. The flux sensor output is continuously received into memory while the the flux sensor output for each phase half-cycle is processed to continuously compute and re-compute in real time a flux-second integral for each half-cycle. The two half-cycle flux-second integrals are compared to each other for a DC offset value and the offset value drives a slow loop DC compensation circuit to steer a PWM control.

Abstract: A communication system includes a primary apparatus and a plurality of secondary apparatuses connected in a daisy chain to the primary apparatus. In each of the secondary apparatuses, a detecting unit detects a current. In response to a switching unit being in an on state, the switching unit allows a current from a primary apparatus to be applied to a detecting unit of at least one other secondary apparatus that is positioned further toward the primary apparatus side than own secondary apparatus is. In response to the switching unit being in an off state, the switching unit allows the current from the primary apparatus not to be applied to the detecting unit of the at least one other secondary apparatus and the detecting unit of the own secondary apparatus. A secondary control unit sets an ID of the secondary apparatus based on a detection result of the detecting unit.

Abstract: A power control system is provided for AC mains, including an input bridge rectifier connected to the AC power mains, and a buck regulator circuit connected to the DC output of the input bridge rectifier, the output of the buck regulator circuit providing a DC power output bus. A current sensor is connected to the output of the buck regulator circuit, and one or more capacitors is connected across the DC power output bus for receiving current from the buck regulator circuit. The buck regulator circuit is controlled to limit peak output current thereof.

Abstract: Provided is a method of operating an electrical system including a first battery, a second battery coupled in series with the first battery, and a battery equalizer coupled to the first battery and the second battery and configured to supply an equalizing current to the first battery. The method includes monitoring a level of the equalizing current, determining, based on monitoring of the level of the equalizing current, that the equalizing current is saturated, and reducing a level of current supplied at a positive terminal of the first battery in response to determining that the equalizing current is saturated. The methods may take an action to reduce the demand for current that is supplied by the first battery.

Abstract: A device charging system includes a legacy battery-powered mobile electronic device configured for wired-only charging and a wireless charging enabled battery pack. The wireless charging enabled battery pack may contain one or more battery cells as well as a power management integrated circuit (IC) configured to manage charging of the battery cells. The wireless charging enabled battery pack also contains a wireless power module to receive power wirelessly from a WPT (wireless power transfer) power source outside of the legacy device. In keeping with embodiments of the disclosure, a pack microcontroller in the battery pack interfaces to the legacy device, presenting an interface consistent with a wired-only charged battery pack.

Abstract: Power management techniques are disclosed. For instance, an apparatus may include a bidirectional voltage converter circuit, and a control module that selectively operates the bidirectional voltage converter circuit in a charging mode and a delivery mode. The charging mode converts a voltage provided by an interface (e.g., a USB interface) into a charging voltage employed by an energy storage module (e.g., a rechargeable battery). Conversely, the delivery mode converts a voltage provided by the energy storage module into a voltage employed by the interface. Other embodiments are described and claimed.

Abstract: In accordance with disclosed embodiments, a power conversion system and method are provided. The power conversion system comprises a main power source configured to deliver drive power to a load and an add-on power module. The add-on power module comprises an isolated DC/DC converter and a low voltage source coupled in series with a high voltage source. The add-on power module is coupled to the main power source and the load and configured to output boost power to the load. The power conversion system further comprises a controller coupled to the main power source and the add-on power module, wherein the controller is configured to: determine that the load requires power from the main power source, and if so, direct boost power from the add-on power module to the load; and direct drive power from the main power source to the load when boost power falls below a predetermined threshold.

Abstract: Disclosed herein is a control circuit of an isolated power supply including a first transformer and a primary-side transistor connected to a primary winding of the first transformer. The control circuit includes a timing generator that generates a timing signal with reference to an edge of a switching signal generated on a secondary side of the isolated power supply, a sampling circuit that, in response to the timing signal, samples an electric signal to be monitored, the electric signal to be monitored being an electric signal on the secondary side of the isolated power supply, and a feedback controller that, based on an output of the sampling circuit, generates a primary-side pulse signal to be supplied to the primary-side transistor.

Abstract: A solar array power generation system includes a solar array electrically connected to a control system. The solar array has a plurality of solar modules, each module having at least one DC/DC converter for converting the raw panel output to an optimized high voltage, low current output. In a further embodiment, each DC/DC converter requires a signal to enable power output of the solar modules.

Abstract: In a power supply system and a method for controlling the same, at least one battery from among a plurality of batteries is designated as a charging-side battery, and the remaining batteries are designated as discharging-side batteries. Next, the difference in current between the current flowing from the discharging-side batteries and the current flowing into the charging-side battery is determined on the basis of currents measured by a plurality of current measuring instruments. Next, the transformation rate of a voltage transformer connected to the discharging-side batteries is determined on the basis of the determined difference in current.

Abstract: A system for preventing magnetic saturation and for controlling and managing DC offset in a transformer cores. A magnetic flux sensor is disposed within a bore within the core transformer core. The sensor transmits a sensor output that is continuously received by a processor that is programed to continuously compare in real time the sensor output with a stored selectable maximum flux sensor output value. Responsive to the comparison of real-time sensor output value to the stored maximum value, the microprocessor either allows, during each driving voltage half-cycle, the driving voltage to continue unabated while the sensor output remains below the selectable maximum value, or triggers a gate to modify the driving voltage for the remainder of the half-cycle when the selectable maximum value is reached.

Abstract: A system and method for combining power from DC power sources. Each power source is coupled to a converter. Each converter converts input power to output power by monitoring and maintaining the input power at a maximum power point. Substantially all input power is converted to the output power, and the controlling is performed by allowing output voltage of the converter to vary. The converters are coupled in series. An inverter is connected in parallel with the series connection of the converters and inverts a DC input to the inverter from the converters into an AC output. The inverter maintains the voltage at the inverter input at a desirable voltage by varying the amount of the series current drawn from the converters. The series current and the output power of the converters, determine the output voltage at each converter.

Abstract: Various aspects of invention provide portable power manager operating methods. One aspect of the invention provides a method for operating a power manager having a plurality of device ports for connecting with external power devices and a power bus for connecting with each device port. The method includes: disconnecting each device port from the power bus when no external power device is connected to the device port; accessing information from newly connected external power devices; determining if the newly connected external power devices can be connected to the power bus without power conversion; if not, determining if the newly connected external power devices can be connected to the power bus over an available power converter; and if so, configuring the available power converter for suitable power conversion.

Abstract: A flying capacitor (FC)-type 3-level power conversion device turns on or off first to fourth semiconductor switching elements based on comparison between a flying capacitor voltage and a half of higher-voltage side filter capacitor voltage, comparison between the higher-voltage side filter capacitor voltage and the flying capacitor voltage plus a lower-voltage side filter capacitor voltage, comparison between the flying capacitor voltage and the lower-voltage side filter capacitor voltage, and comparison between the lower-voltage side filter capacitor voltage or the higher-voltage side filter capacitor voltage and a filter capacitor voltage command value, so that an electric current flows along a path including a filter reactor L and charging a flying capacitor so as to charge a lower-voltage side filter capacitor or a higher-voltage side filter capacitor to predetermined values.

Abstract: Distributed maximum power point tracking systems, structures, and processes are provided for power generation structures, such as for but not limited to a solar panel arrays. In an exemplary solar panel string structure, distributed maximum power point tracking (DMPPT) modules are provided, such as integrated into or retrofitted for each solar panel. The DMPPT modules provide panel level control for startup, operation, monitoring, and shutdown, and further provide flexible design and operation for strings of multiple panels. The strings are typically linked in parallel to a combiner box, and then toward and enhanced inverter module, which is typically connected to a power grid. Enhanced inverters are controllable either locally or remotely, wherein system status is readily determined, and operation of one or more sections of the system are readily controlled. The system provides increased operation time, and increased power production and efficiency, over a wide range of operating conditions.

Abstract: This application provides a photovoltaic power generation system. The system includes at least one first photovoltaic module, a photovoltaic inverter, a first two-way DC/DC converter, and at least one first energy storage unit, and further includes at least one second photovoltaic module or at least one second energy storage unit. The photovoltaic inverter includes a DC/DC converter and a DC-AC inverter, where the DC/DC converter is electrically connected to the at least one first photovoltaic module, and the DC/DC converter is connected to the DC-AC inverter through a direct current bus. For the photovoltaic power generation system, photovoltaic arrays and energy storage devices can be configured flexibly to cope with peaks and troughs of power consumption.

Abstract: An apparatus includes a first group of switches connected in series, a second group of switches connected in series, a first flying capacitor between a first common node and a third common node of the first group of switches, a second flying capacitor between a first common node and a third common node of the second group of switches, wherein the first group of switches and the second group of switches are configured such that the apparatus operates in one of three operating modes including a bypass operating mode, a hybrid operating mode and a boost/buck operating mode.

Abstract: A power conversion module, a vehicle-mounted charger, and an electric vehicle may be used in the field of new energy vehicles. The power conversion module includes a power factor correction PFC module and a first direct current-direct current DC-DC converter. A first primary circuit of the first DC-DC converter has a first bridge arm, a second bridge arm, a third bridge arm, and a fourth bridge arm. A first switch is disposed between the first bridge arm and an inductor at an interface of the PFC module, and a second switch is disposed between the third bridge arm and another interface of the PFC module.

Abstract: A high-frequency electromagnetic induction control circuit includes a charging control circuit, a battery control and protection circuit, a battery, a main control MCU, a display control circuit, a keyboard control circuit, a drive circuit, a high-frequency heating circuit, and an induction heating circuit. The charging control circuit supplies a charging voltage and a charging current for the battery. The battery control and protection circuit is configured to detect whether the charging voltage and the charging current are qualified. The battery supplies power for the main control MCU. The main control MCU is configured to detect an input voltage of the battery, and the display control circuit sends out a signal whether the battery is in an under-voltage state. The keyboard control circuit is configured to control the main control MCU to operate. The output voltage of the main control MCU is boosted by the drive circuit.

Abstract: The present invention discloses a flying capacitor converter, a short circuit current suppression circuit for the same and an energy storage system. The flying capacitor converter comprises a controller, and has a high voltage side connected to a first power source and a low voltage side connected to a second power source. The short circuit current suppression circuit comprises: at least one current detection unit connected to the low voltage side and/or the high voltage side of the flying capacitor converter; and at least one switch set connected in series to the high voltage side and/or the low voltage side of the flying capacitor converter, wherein the controller controls the switch set to cut off a connection between the flying capacitor converter and the first power source and/or between the flying capacitor converter and the second power source, when the current detection unit detects a short circuit.

Abstract: A power converter includes a network of switches having a first capacitor switch coupled to a first flying-capacitor, a first switch to couple a second flying-capacitor to a first port, an inductor coupled to a ground switch. A driver drives the network of switches in two states. In the first state the ground port is coupled to a second port via a first path comprising the first flying-capacitor and the inductor, and the first port is coupled to the second port via a second path comprising the first switch, the second flying-capacitor and the inductor. In the second state the ground is coupled to the second port via a third path comprising the ground switch and the inductor, and one of the first port and the ground port is coupled to the second port via a fourth path comprising the first flying-capacitor while bypassing the inductor.

Abstract: A power electronics assembly for a mobile application includes a first power electronics component selectively coupled to a high source on a first side and coupled to a high voltage battery on a second side, a second power electronics component selectively coupled to one of a low load or a low voltage battery on a first side and coupled to the high voltage battery on a second side; and a controller, including an operating mode circuit structured to determine a discharge operating mode for the mobile application, a power electronics configuration circuit structured to provide a switch state value for the first power electronics component and the second power electronics component in response to the discharge operating mode, and wherein the first power electronics component and the second power electronics component are responsive to the switch state value to coupled selected ones of the high source, low load, and low voltage battery to the high voltage battery.

Abstract: To provide a sensor apparatus and sensor system using a low-power input source such as a microbial fuel cell, provided is a sensor apparatus including a microbial fuel cell; a boosting DC-DC circuit that operates based on an input voltage from the microbial fuel cell and boosts the input voltage; a power storage element that stores power output from the boosting DC-DC circuit; and a sensor element that operates based on power output from the power storage element, as well as a sensor system that includes this sensor apparatus and a wireless communication apparatus.

Abstract: An energy system for an electrically-driven vehicle is provided along with methods for operating the energy system. The energy system has a low-voltage charging function and an active load-balancing system for traction batteries.

Abstract: A charging device provides the ability to fast charge various personal electronic devices in a wireless manner without being tethered by a cable. The charging device includes a first housing with an input charging port and an output charging port. A charging adapter is fashioned as a second housing with an AC power adapter and a plurality of charging jacks, each capable of receiving the input charging port of the first housing.

Abstract: Systems and methods for modular charging of vehicles are described. For example, a method may include connecting a vehicle to a charger using a charging plug interface that includes a first pair of conductors connected to alternating current terminals of an on-board alternating current-to-direct current converter of the vehicle and a second pair of conductors connected to terminals of a battery of the vehicle; and charging the battery of the vehicle via direct current flowing through the second pair of conductors concurrent with charging of the battery via alternating current flowing through the first pair of conductors to power the on-board alternating current to direct current converter.

Abstract: An input module may include a first resistor and a second resistor coupled in series with the first resistor. The input module may also include a switch that may electrically isolate the second resistor based on a voltage output by an additional input module electrically coupled to the input module via a terminal base.

Abstract: The present invention relates to a wireless charging system including a boost converter and a transmission coil structure at a transmission side. The wireless charging system includes a boost converter 150 configured to boost a first DC voltage input to an input terminal to a second DC voltage, a DC/AC inverter 160 configured to receive the boosted second DC voltage from the boost converter to convert the received second DC voltage to AC power, and a transmission coil structure 170 which is electrically connected to the DC/AC inverter to generate a temporally variable magnetic field for wireless supplying from the AC power. The first DC voltage and the second DC voltage of the boost converter 150 may be maintained to predetermined fixed values. The transmission coil structure 170 is formed by winding a wire on a magnetic sheet many times in a spiral shape and the winding coil has a circular shape having predetermined inner radius and outer radius, a pitch, and the turn number.

Abstract: An energy distribution system. The energy distribution system has a housing with a rear terminal and a front terminal. An inlet unit receives air therethrough. The inlet unit then passes the air through a one-way valve into a reservoir where the air molecules undergo ionization. Once ionized, the gaseous air is converted into a plasma state. After being converted into the plasma state, electric energy is generated by a pair of magnets and stored in a capacitor.

Abstract: This power conversion device includes: a power conversion unit 20 provided between a DC power supply 2 and an AC electric path 3 and configured to perform DC/AC power conversion; and a control unit 14 configured to control the power conversion unit 20. The control unit 14 includes a determination unit 25 configured to determine whether or not a starting current has flowed through the AC electric path 3, and an adjustment unit 26 configured to adjust an AC voltage generated by the power conversion unit 20, on the basis of a result of the determination by the determination unit 25.

Abstract: Various embodiments are directed to methods for use with a surgical device to harvest energy from a surgical generator. The surgical device in use in conjunction with the surgical generator may comprise an energy storage device in electrical communication with a surgical generator to provide energy to charge the energy storage device. The method may comprise the steps of receiving a drive signal from the generator. The method may also comprise directing at least a portion of the drive signal to the energy storage device in a first mode. The method may further comprise directing at least a portion of the drive signal to at least one energy element in a second mode.

Abstract: A switching cell includes: a half-bridge circuit including a first electronic switch and a second electronic switch connected in series between a first input terminal and a second input terminal of an electronic converter, wherein a first capacitor is connected in parallel to the first electronic switch and a second capacitor is connected in parallel to the second electronic switch; a first inductor connected between a first output terminal of the electronic converter and an intermediate point between the first electronic switch and the second electronic switch; a second inductor and a first capacitor connected in series between a first terminal of the first inductor and the intermediate point; a switching circuit connected between the first terminal of the first inductor and a second output terminal of the electronic converter; and a third capacitance connected between the first terminal of the first inductor and the second input terminal.

Abstract: Smart batteries and smart battery systems are disclosed. A smart battery may include an energy-storage unit providing a cathode tab and an anode tab. The smart battery may also include a circuit integrated with the energy-storage unit. The circuit may be configured to provide electrical connections to the cathode tab and the anode tab of the energy-storage unit to an external device; measure a current, a voltage, a temperature, and/or an internal resistance of the energy-storage unit; control an input/output property of the energy-storage unit; and establish a data connection with the external device.

Abstract: The invention concerns a measurement unit including: an electric ambient energy recovery generator; an element of capacitive storage of the electric energy generated by the generator; an electric battery; a first branch coupling an output node of the generator to a first electrode of the capacitive storage element; a second branch coupling a first terminal of the battery to the first electrode of the capacitive storage element; and an active circuit capable of transmitting a radio event indicator signal each time the voltage across the capacitive storage element exceeds a first threshold, wherein, in operation, the capacitive storage element simultaneously receives a first charge current originating from the generator via the first branch and a second charge current originating from the battery via the second branch.

Abstract: An object of the present invention is to provide a charging apparatus having high efficiency of charging a battery by inputting an alternating current voltage. A charging apparatus that charges a direct current battery includes a step-down converter unit to which a direct current voltage from a power supply is input and that converts the direct current voltage, and when a voltage of the direct current battery is between a predetermined first voltage smaller than a charge completion voltage of the direct current battery and the charge completion voltage, a variable voltage that increases from the first voltage to the charge completion voltage in accordance with charging of the direct current battery is input to the step-down converter unit.

Abstract: In some embodiments, a cooling system for an induction charger includes a thermal conditioning module in fluid communication with an induction charging assembly, which includes a dock and an induction charging module. The dock can be configured to receive a portable electronic device, such as a cell phone, that is configured to accept inductive charging from the induction charging module. The thermal conditioning module can include a fan or other fluid encouraging assembly, ducting, and a thermoelectric device (e.g., a Peltier device). A fluid, such as air, can flow from the fan and across and/or through the thermoelectric device, thereby conditioning the fluid. The conditioned fluid can be provided to the dock to at least partially offset the heat generated by the inductive charging and/or the portable electronic device.

Abstract: According to some embodiments, a bi-directional converter is configured to operate in a boost mode or a buck mode. The bi-directional converter includes a hysteresis control unit that includes a comparator that can be configured to determine whether the reference voltage has a positive slope or a negative slope in conjunction with the bi-directional converter operating in boost mode or buck mode. In addition, the comparator is configured to compare a fractional load voltage to a reference voltage so that the output load voltage corresponds to the waveform shape of the reference voltage.

Abstract: An apparatus for charging a plurality of series connected battery cells, includes a first and second input terminals for providing a charging voltage to the plurality of series connected battery cell. A transformer includes a primary side associated with the charging voltage and a secondary side includes a plurality of portions. Each of the plurality of portions is connected across at least one of the plurality of series connected battery cell. A switch in series between each of the plurality of portions of the secondary side and the at least one of the plurality of series connected battery cells increases an impedance between the portion of the secondary side and the associated one of the plurality of series connected battery cells in a first state and decreases the impedance between the portion of the secondary side and the associated one of the plurality of series connected battery cells in a second state.