A cordless system has cordless system components that include a cordless device, such as a cordless power tool, a battery pack and a charger. The battery pack is mated with either the cordless device to provide power to operate the cordless device or to the charger to charge the battery cells in the battery pack. In an aspect, the cordless system has an identification and communication system by which the battery pack identifies and communicates information about the battery pack to the cordless device or to the charger to which the battery pack is mated. In an, the battery pack of the cordless system is capable of multiple modes, such as controlling the cordless device and controlling the charger. In an aspect, the battery pack validates the cordless device or charger to which it is mated. in an aspect of the invention, the cordless system uses any of a wired interface, radio frequency interface, an optical interface or a magnetic interface to communicate information between the battery pack and the cordless device or charger to which the battery pack is mated. In an aspect, female terminals are used in a terminal block of the battery pack to protect against foreign objects contacting the terminals. In aspect, the terminals in the terminal block of the battery pack are staggered or scattered to reduce the likelihood of a short circuit. In an aspect of the invention, the battery pack has a trap door that closes when the battery pack is not mated to a cordless device or charger to protect the terminal block of the battery pack. In an aspect of the invention, multi-spring, split contact terminals are used in the terminal block of at least one of the cordless system components. In an aspect of the invention, the battery cells are Lithium Ion battery cells.

Cordless power system

To prevent a battery from being over-discharged and to thus improve a cycle life of the battery, a microcomputer electrically interrupts connection between the battery and a cordless power tool to compulsorily stop driving the tool when the battery voltage has become equal to or fallen below a first predetermined value. Also, to enable an operator to know that the battery is in a near over-discharge condition, the microcomputer performs a switching control of a load current when the battery voltage is above the first predetermined voltage but has become equal to or falls below the second predetermined voltage. As a result, the rotation of the motor of the tool goes abruptly slow down or the motor rotates in an irregular fashion, whereby the operator recognizes that the battery is in a charge-need condition.

Battery pack and cordless power tool using the same as power source

A power supply system capable of supplying power from a power transmitter to a power receiver in an electrically non-contact manner, in which a power transmission module is attached to the power transmitter and a power reception module is attached to the power receiver. The power transmission module has a plurality of transmission-side coils for transmitting power and a plurality of transmission-side switches for turning on/off operation of the transmission-side coils. The power reception module has a plurality of reception-side coils for receiving power, a plurality of reception-side switches for turning on/off operation of the reception-side coils and, further, has a determination circuit for performing control so as to operate any of the transmission-side coils and any of the reception-side coils in a combination realizing highest power transmission efficiency.

Non-contact power supply system

A power supply system is provided, having: a primary side coil; a power transmission apparatus having a primary side circuit for feeding a pulse voltage resulted from switching a DC voltage which is obtained by rectifying and smoothing a commercial power supply to the primary side coil; a secondary side coil magnetically coupled to the primary side coil; and power reception equipment having a secondary side circuit for rectifying and smoothing voltage induced across the secondary side coil, wherein there is provided a power adjusting section for adjusting a level of power to be transmitted according to power required by the power reception equipment. The power adjusting section has, in the primary side circuit, a carrier wave oscillation circuit for supplying a carrier wave to the primary side coil, a demodulation circuit for demodulating a modulated signal transmitted from the secondary circuit and received by the primary side coil, and a power change-over section for selecting a level of power to be transmitted according to an information signal from the power reception equipment and demodulated by the demodulation circuit. The power adjusting section has, in the secondary side circuit, a modulation circuit for modulating the carrier wave fed from the carrier wave oscillation circuit and received by the secondary side coil with the information signal from the power reception equipment and transmitting the modulated signal.

Power supply system

Power supply systems and methods are provided. In one aspect, a power supply system includes a frame, a power input to receive input power from a power source, a power output to provide output power to a load, at least one battery module mounted in the frame and having a battery output that provides battery power, at least one power module mounted in the frame and coupled to the power input to receive the input power, coupled to the battery output to receive the battery power, and coupled to the power output to provide the output power from at least one of the battery power and the input power, a first controller coupled to the at least one power module, and a second controller, substantially similar to the first controller, coupled to the first controller, and coupled to the at least one power module, wherein each of the first controller and the second controller are configured to determine operational parameters of the power supply system and store a first set of parameters determined by the first controller and a second set of parameters determined by the second controller.

Method and apparatus for providing uninterruptible power

An uninterruptible power system has a transformer with a primary connected to input terminals, a secondary connected to output terminals, a static switch connected between the input terminals and the primary, and an auxiliary primary connected to an inverter which is supplied by a battery to provide output voltage to the output terminals when a main AC power system connected to the input terminals has failed. The primary has multiple taps at different voltage levels and a buck-boost winding. The taps of the transformer are switched and the buck-boost winding is controlled to provide either buck, boost, or pass-by to allow control of the output voltage from the transformer to within a few percent of a desired voltage level despite large changes in the input voltage. A battery charger coupled to the auxiliary primary operates as a boost converter to provide current to charge the battery at a current level which tracks the input voltage from the AC power system, thereby providing a substantially unity power factor to the AC power system. The voltage control of the output voltage also controls the voltage at the output of the auxiliary primary to which the battery charger is connected, whereby the voltage applied to the charger is substantially regulated and the output power of the charger itself is substantially regulated. The charger can be operated in programmable modes to provide a desired charge configuration for the battery. Detection of faults in the AC power system is enhanced by accurate detection of the zero crossings of the input voltage from the AC power system, and by comparison of the AC input power waveform with an adaptive reference.

Uninterruptible power system

A back-up uninterruptible power system has a power supply path from input terminals connected to AC power system lines to normally supply power to a load. Upon the occurrence of a line fault, a static switch in the power supply path interrupts the connection between the AC power lines and the load and an inverter is turned on to provide power derived from an auxiliary battery through a transformer to the power supply path to supply AC power to the load. By using the static switch, switching from line connection to backup power can be done quickly, within a half cycle, so that substantially no interruption of the output waveform is observed. The inverter can be operated to provide a commutation pulse to the SCRs in the static switch to commutate an SCR which might otherwise continue conducting after the triggering signals to the gates are cut off and before the inverter supplies the AC power to the load. A relay connected between the input terminals and the static switch is controlled to open relay contacts after the static switch has interrupted the current flow to the load, thereby providing positive electrical isolation of the AC power system from the uninterruptible power system while allowing the mechanical relay contacts to switch only during times of no current. Line fault detection is carried out by creating a digital waveform composed of an average of prior cycles of the AC input waveform, converting the stored waveform to an analog signal, and comparing it with the present input signal in phase lock therewith to detect deviation of the input signal from the reference waveform.

Back-up uninterruptible power system

Power compensation is provided from a power compensation device (30) to a utility power network (20) carrying a nominal voltage. The power compensation device has a steady-state power delivery characteristic. The power compensation is provided by detecting a change of a predetermined magnitude in the nominal voltage on the utility power network and controlling the power compensation device to deliver, for a first period of time and in response to the detected change in the nominal voltage, reactive power to the utility power network. The power compensation device is controlled to deliver, for a second period of time following the first period of time, reactive power to the utility power network at a level that is a factor N (N>1) greater than the steady-state power delivery characteristic of the power compensation device.

Voltage regulation of a utility power network

The run-time available from an uninterruptible power system is accurately determined both during supply of power from the battery to the load and during the time where power is supplied directly from an AC power system to the load. During power outages, where power is supplied from the battery through the inverter to the load, the remaining run-time is first estimated by calculation and then corrected by modification of the calculated value according to the reciprocal of the run-time slope. Alternatively, a scaling factor is used as part of the first run-time calculations and a correction factor which applies more corrective weight as the time on inverter progresses may be used. During power outages and when power is supplied from the AC power system to the load the maximum available run-time is extrapolated from a table of values representing maximum available run-times at various levels of power being supplied to the load from a fully charged battery. These values are updated after inverter runs to reflect actual system run-times. The maximum run-times are thereby adapted to reflect battery aging and other unique characteristics of the system.

Method and apparatus for adaptive and corrective determination of battery run-time in uninterruptible power systems

Power is provided from an energy storage device to a utility network based on a detected condition, such as a fault, in the network. Specifically, it is determined whether a fault on the utility network is a near fault or a far fault relative to the energy storage device. Whether a fault is classified as 'near' or 'far' is determined based on a voltage drop in the utility network. Power is then supplied to the utility network based on whether the fault is a near fault or a far fault.

Thomas G Hubert

Papers

Uninterruptible power system

Back-up uninterruptible power system

Voltage regulation of a utility power network

Method and apparatus for adaptive and corrective determination of battery run-time in uninterruptible power systems

Method and apparatus for providing power to a utility network