摘要:
A spread-spectrum power converter uses an inter-cycle duty-cycle error compensation to achieve a combination of high-precision tracking of a target average duty cycle and a favorable noise signature. The pulse train consists of a series of cycles having cycle durations of a positive integer of clock cycles, pulse durations of a whole number of clock cycles, and duty cycles corresponding to a ratio of pulse durations over cycle durations. The pulse durations are selected at least in part as functions of a target average duty cycle, the respective cycle durations, and a ripple (or other) error from other cycles in the train. The cycle durations can also be in part a function of the target average duty cycle so that the duty cycle errors can be minimized.
摘要:
A power conservation system (PCS) includes a data handler, a controller and a power switch. The data handler is located between a host network and a network printer, while the power switch is between an AC power source and the printer's power input. The PCS can thus shut down the printer during periods when no data is being sent to the printer. The PCS monitors data to and from the printer, allowing it to track the printer's state and to capture its network identification. State tracking permits the PCS to emulate the printer when it is down and when it is booting. Additionally, the information stored in a state memory of the data handler can permit the printer's last ready state to be reconstructed after it turns on and boots to a ready state. In some cases, the data handler can answer network requests without turning on the printer. Thus, the PCS provides for effective power conservation while remaining invisible to a user.
摘要:
A phase-controlled power delivery system for a load such as an incandescent lamp controls the rate of transition of an AC power waveform as a function of switch temperature or other heat-related parameter to provide for time-varying optimization of a tradeoff between heat and noise.
摘要:
A spread-spectrum power converter uses an inter-cycle duty-cycle error compensation to achieve a combination of high-precision tracking of a target average duty cycle and a favorable noise signature. The pulse train consists of a series of cycles having cycle durations of a positive integer of clock cycles, pulse durations of a whole number of clock cycles, and duty cycles corresponding to a ratio of pulse durations over cycle durations. The pulse durations are selected at least in part as functions of a target average duty cycle, the respective cycle durations, and a ripple (or other) error from other cycles in the train. The cycle durations can also be in part a function of the target average duty cycle so that the duty cycle errors can be minimized.
摘要:
A phase-controlled power delivery system for a load such as an incandescent lamp controls the rate of transition of an AC power waveform as a function of switch temperature or other heat-related parameter to provide for time-varying optimization of a tradeoff between heat and noise.
摘要:
A phase-controlled power modulation system switches modes in response to circuit-threatening conditions to avert the necessity of a shutdown. Normal operation is in reverse phase control (RPC) mode. When an inductive load sensor detects the presence an inductive load, the system switches to a forward phase control (FPC) mode (FPC) to minimize voltage spikes that would otherwise result from the load's opposition to voltage transitions. When an overcurrent sensor detects an overcurrent, the system switches into an asymmetric hybrid mode (AHPC) to maximize delivered power while remaining within switch current handling capacity. In AHPC mode, an RPC component of a half-cycle waveform is cut off at the current limit, while an FPC component of the same half-cycle waveform is triggered after the source voltage drops to a confidence threshold below the current limit to ensure that current limiting is not triggered again during the same half-cycle. In response to excessive temperature, a short transition mode is entered to reduce the heat generated at the switches until the temperature abates.
摘要:
A refrigerated appliance that dispenses items includes a power source and a cooling system. Power control circuitry is electrically coupled between a power source (e.g., power cord coupled to a wall outlet) and components (for example, a compressor and one or more circulating fans of the cooling system) of the appliance. A controller, which is operably coupled to the power control circuitry, is adapted to manage the supply of electrical power to such components by intelligently transitioning between a normal-operation mode and at least one power-conserving mode. To achieve efficient power conservation, the controller automatically transitions between the at least one power-conserving mode and the normal-operation mode based upon at least one temperature signal, at least one dispensing event signal, and possibly other data signals supplied to the controller.
摘要:
A refrigerated vending machine provides separate power conservation modes for the cooling system and the panel lights. Power conservation for the panel lights takes into account whether the vending machine is located indoors or outdoors. The location can be indicated by a setting by the vending machine operator or may be determined automatically according to maximum brightness or color temperature. If the vending machine is outdoors, the panel lights are turned off when the ambient is bright (to save energy when the panel lights are not needed) and turned on when the ambient is dark (to attract customers). If the vending machine is indoors, the panel lights are turned off when the ambient is dark (since the room is presumably vacant) and turned on when the ambient is bright (indicating the room is in use). Optionally, an occupancy sensor can be used to turn off the panel lights if the room light is on but no one has been detected in it. The cooling system uses a conservation mode in which circulation fans are switched off so only items in a position to be dispensed first or second are kept at the desired temperature.
摘要:
A refrigerated soda vending machine includes sensors for monitoring various parameters such as temperature within its refrigerated chamber and for monitoring occupancy in the chamber vicinity. Sensor data is used to determine when to switch between normal and power-conservation modes of operation. In either mode, a cooling system is regulated so that a compressor goes on when an upper internal temperature threshold is reached and off when a lower internal temperature threshold is reached. In normal mode, fans circulate air to maintain a relatively uniform temperature throughout the chamber. During power-conservation mode, the fans are mostly off when the compressor is off. In the absence of circulation, the temperature within the refrigerated chamber stratifies so that a lower cool zone and an upper warm zone can be differentiated. Soda cans are held in vertical stacks so that the lowest cans are located in the cool zone.
摘要:
An external power-management device controls the supply of electric power from a wall outlet to a refrigerated vending machine. The system includes a switch that couples power in an ON condition and decouples in an OFF condition. The switch is controlled by a controller based on data received from a current sensor, an occupancy sensor, a temperature sensor, and a time-of-year circuit. Upon startup, the current is monitored to determine maxima and minima for the vending machine. The system supplies power to the appliance during business hours as indicated by the time-of-year circuit and while the vicinity is occupied as determined by the occupancy sensor irrespective of the values for current and temperature. Absent the current sensor, the power would be decoupled after a predetermined duration of non-occupancy during nonbusiness hours. However, if the current sensor indicates a high (relative to the previously determined minima and maxima) current at the proposed shutdown time, shutdown is aborted to avoid interruption of a compression (cooling) cycle initiated by the vending machine. The temperature is used in determining when, after shutdown, power is resumed to permit vending machine contents to be cooled.