Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
  • F25D29/00—Arrangement or mounting of control or safety devices
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B49/00—Arrangement or mounting of control or safety devices
  • F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B2600/00—Control issues
  • F25B2600/02—Compressor control
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B2600/00—Control issues
  • F25B2600/11—Fan speed control
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
  • F25B2700/17—Speeds
  • F25B2700/171—Speeds of the compressor
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
  • F25B2700/17—Speeds
  • F25B2700/172—Speeds of the condenser fan
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
  • F25B2700/17—Speeds
  • F25B2700/173—Speeds of the evaporator fan

Definitions

• the invention generally relates to refrigeration systems and controllers.
• the invention relates to refrigeration systems and controllers which are used to control electronically commutated (EC) motors and carry out other functions in addition to controlling motors.
• EC electronically commutated
• Beverage coolers are one type of refrigeration system utilized throughout the world to provide cost effective storage and delivery of consumable products in retail stores and other public distribution points. Beverage coolers utilize cooling devices to maintain the product at a serving temperature below the ambient temperature.
• the cooling devices typically include a compressor to compress a refrigerant, a condenser to condense the refrigerant and an evaporator to evaporate the refrigerant, as is well known. Internal cabinet lighting may also be provided.
• system controller may include the facility to accept input from one or more activity detectors such as door switches and movement sensors, and a real-time clock, thus allowing the storage temperature to be automatically adjusted to minimise power consumption during low-usage periods such as store closing hours, thus minimising operating costs.
• activity detectors such as door switches and movement sensors
• real-time clock a real-time clock
• the invention consists in a refrigeration system containing at least one motor driven refrigerant compressor, at least one motor driven fan, at least one temperature sensor, and a refrigeration system controller, at least one of the compressor or fan motors being an electronically commutated motor, and the refrigeration system controller containing at least one microprocessor determining the commutation of at least one of the electronically commutated motors driven from the system controller and the operation of any other motors in the refrigeration system, the microprocessor additionally determining the operation of at least said electronically commutated motor in relation to the temperature sensor output.
• the microprocessor receives inputs from or provides outputs to other ancillaries of the refrigeration system.
• the microprocessor receives inputs from door position sensors, fan speed sensors, and other environment sensors and determines the operating conditions of any motors from these inputs.
• the system controller contains means to switch on and off any motors which are not commutated by the system controller in response to signals from the temperature sensing means.
• the algorithm by which the motors and any other external devices are controlled includes inputs from presence detecting means such as door status, vibration, or motion detection
• the algorithm by which motors and any other external devices are controlled includes a history of presence data recorded over a period of at least a day
• the algorithm by which motors and any other external devices are controlled includes inputs received from a user interface or other programming means
• the system controller also contains means to convert mains-voltage input power into one or more low voltage outputs suitable for driving LED lighting.
• this means also supplies low voltage power to the at least one microprocessor and to other low voltage electronics within the controller
• system controller commutates more than one motor all motors commutated share a common high voltage DC supply
• a method of controlling a refrigeration system having at least one electronically commutated motor and other electrical ancillaries by:
• the method includes controlling any cooling fan motors using the microprocessor.
• the method includes detecting any stalled fan motors using the microprocessor.
• the method includes controlling the refrigeration system lights from the microprocessor.
• the method includes providing a single low voltage power supply for the microprocessor and the lighting system.
• the method includes providing a single high voltage DC supply for the motors commutated by the system
• the microprocessor controls a refrigeration system compressor in accordance with the refrigeration temperature.
• FIG. 1 is a block diagram of a known electronically commutated refrigeration system motor controller.
• FIG. 2 is a block diagram of a typical known beverage cooler system controller.
• FIG. 3 is a block diagram of an integrated refrigeration controller which includes electronically commutated control of three motors and control of LED lighting and other functions.
• FIG. 4 is a possible process flow control for the initializaton of such a refrigeration controller.
• FIG. 5 is a process flow diagram of other controlled portions of the inventive beverage cooler. Description of the Invention
• FIG. 1 a block diagram of a typical known electronically commutated motor controller 101.
• This controller 101 includes mains input 102 to a mains inputs processing stage 103, which typically comprises electronic noise suppression, inrush current suppression, fusing, and may also include power factor correction.
• a high voltage DC bus stage 104 rectifies the mains and provides a high voltage DC supply capable of providing the high currents to a motor controller 107 which powers the motor, in this case an evaporator fan motor 108.
• a low voltage power supply 105 derived from the high voltage supply 104 reduces the DC voltage to a suitable level to power the control electronics for a microprocessor 106 and smoothes it to an acceptable standard for reliable functionality.
• a power stage feeds current from the high voltage supply to the motor under control of the microprocessor 106 and may pass signals to the microprocessor 106 which can be used to infer motor status parameters such as rotor position and speed.
• FIG. 2 a block diagram 201 of a typical known beverage cooler refrigeration system controller is shown.
• This includes a mains input processing stage 203 for mains supply 202 similar to that described above, a low voltage power supply 210, a microprocessor 212 which takes inputs from a real-time clock 211, a user interface 214, and several external sensors such as that for temperature at 216 or activity sensors 215. All these inputs are used to calculate when to switch AC power to motors and lighting off and on through a bank of high-current relays at 204, these controlling motors either directly as for condenser fan motor 207 and refrigerant compressor 208 or via a motor controller 205 such as is described with reference to FIG. 1.
• a motor controller 205 such as is described with reference to FIG. 1.
• a mains input processing block 303 similarly cleans the mains input before supplying it to a high voltage DC supplier 304 and also supplies a low voltage converter in the form of DC switch mode power supply 311.
• This supply primarily produces current for the LED lighting 318 associated with illuminating the interior and the advertising of the beverage cooler but also supplies the real time clock 312, the microprocessor 313 and the input conditioning 314.
• the input conditioning at 314 accepts information from temperature sensors 316 and from activity sensors, such as door open position sensors and proximity motion sensors which allow the beverage dispenser to react to changes in its environment.
• the microprocessor provides control for the motor control power stages of the refrigeration system, which electronically commutate one or more of the motors or which may provide simple switched on/off power control of the remaining motors, in each case via power control stages 305, 306, 307 respectively to the evaporator fan motor, the compressor motor or the condenser fan motor. No attempt is made to vary the HVDC supply of 304 since this would require independent control for each motor and a multiplication of the more expensive parts of the power supply.
• Scheduling control of the various ancillaries such as motors and the sensing and response to the various sensors requires careful design of the microprocessor software, since it is important, for instance, that the microprocessor 313 continues to produce the commutator control for evaporator fan motor 308 despite having to control the other motors and react to the sensors and the user interface. For this reason control is split into the primary tasks of controlling the motors, and secondary tasks of monitoring the sensors and reacting to the inputs.
• the secondary tasks may be managed by a low-priority loop which calls low-level subroutines to control detail aspects of motor and system control. This loop and its subroutines may be interrupted by higher-priority interrupts related to the time-critical aspects of controlling the motors.
• FIG. 4 shows one possible control system process flow for the low priority loop in which at step 401 the microprocessor starts the system up at power initiation and then enters a low priority initialization sequence at step 402 in which at step 403 it checks settings such as storage temperature which may have been entered via the user interface. At step 404 it checks the presence history of persons opening the beverage cooler and at step 405 it calculates from this the location status, that is, whether at the current and near future times the location where the cooler is placed can be expected to experience high, low, or zero activity.
• step 406 From these calculations can be performed at step 406 from the system settings for the location including such parameters as a setpoint temperature, the desired lighting status, and maximum fan speeds based on the store status and the user settings. For example if the system calculates that the store has been closed for more than 1 hour, setpoint temperature may be raised and fan speeds reduced, as the beverages need not be kept stably at a desirable drinking temperature, and display lighting may be switched off, while advertising lighting may be left on or off depending on user settings.
• setpoint temperature may be raised and fan speeds reduced, as the beverages need not be kept stably at a desirable drinking temperature, and display lighting may be switched off, while advertising lighting may be left on or off depending on user settings.
• step 407 and 408 the lighting is switched off or on or dimmed to match the settings calculated in step 406, and at step 409 temperature is measured from a temperature sensor and compared with the set point calculated at step 406.
• step 410 motor speed and/or torque targets for fan and compressor motor are calculated and set so as to most rapidly and economically bring temperature closer to target. The general initialization of parameters is now complete.
• Block 411 contains an abbreviated version of a general system sanity check algorithm for each motor on the operating status of the motor which is carried out on a timed interrupt driven basis, but also following initialization.
• the system checks whether the particular motor should be running and if it is currently off the system returns at step 413.
• the motor state is detected, as a speed sensor, measuring whether the motors are actually running, and if so checks at step 415 that the speed and current being drawn , are as expected. If they are then any exception flags which are set are reset at step 416 and the system enters or re-enters the main control loop at step 417.
• the speed/current check at step 415 when failed, results in a comparison of the found conditions at step 424 with those which correspond to the beverage cooler door being open, since this results in a change in the air flow patterns within the cabinet and changes in the motor loading as the air patterns at the door are disturbed compared to the stable situation with the door closed.
• These transient changes can be detected by the microprocessor and correspond to the presence of a person which allows the "door open” flag to be set at step 425 and a recorded presence history updated to show an access at step 426. It may also be used to modify the machine operation to cope with the "door open” condition. When the door is closed again the fan motor should revert to its original running condition, and the door will be recorded as shut.
• step 427 If the change in speed or current is not a "door open" event an attempt is made at step 427 to classify it as another known type of change, for instance one due to a clogged condenser. In such a case the appropriate flag is set at step 428 and control returns to the main loop. Otherwise the condition is analysed as either hazardous or acceptable at step 429, the system shut down to avoid damage at step 419 if hazardous (for instance if the compressor motor is or flagged at step 430 as an alarm condition.
• FIG. 5 shows in block 501 the main control loop 502. Typically this is an idle loop, acting to accept the interrupt driven routines which actually control the motors and monitor the conditions.
• interrupts are event driven interrupts at block 503 and time driven interrupts at block 504.
• the former might be such things as the detection of a "motor stalled" flag, while among the latter could be the increase of the beverage temperature outside the access hours of the location or the occurrence of the regular check of the environment settings and sensor as at block 505.
• a settings and environment check will divert at step 506 to step 403 of FIG. 4 before reentering the motor check routine.
• Fig 5 at block 510 shows one typical subroutine which manages the detail of motor startup.
• this routine which is called from step 418 a request for motor startup is received at step 511.
• a check is made as to whether the motor is actually sustainably rotating at step 512 (in other words that the motor is turning fast enough to be considered started) and if it is not a check is made at step 513 as to whether an excessive number of previous starts have been attempted. If so then there is clearly something in error with the load on the motor, so the motor is marked as stalled at step 514 and control returns to the main loop at step 515 with a stalled exception flag set.
• the motor is aligned at step 516 to a known position, normally by applying current to one phase for a prolonged period.
• Current is then stepped to the next phase at 519 after a predetermined period set at step 517 and timed at step 518, and this is repeated through step 520 at diminishing periods, thus changing phases at the poles and accelerating the motor in an open-loop period, until speed is high enough for an EMF to be detected on the non-actuated phase via the loop to step 512.
• the routine ends by exiting at step 515 and the motor commutates as normal, controlled by interrupt- driven switching routines. If EMF is not detected, the cycle may be repeated several times, until either a successful start is achieved or the motor is determined to be stalled. This routine may be called repeatedly using different parameters to start multiple motors in sequence.
• Fig 5 shows one typical interrupt-driven routine to deal with time-critical tasks, in this case commutating a motor.
• This routine is called whenever one of the motors is detected as having rotated far enough to require commutation.
• the routine is entered at a phase transition step 531 and calculates at step 532 the period since the last commutation, from which instantaneous motor speed can be inferred. If this shows motor speed as too low, the phase current setting is increased to accelerate the motor at step 533. If too high, phase current setting is decreased at step 534 to slow the motor. Power is then switched to the new phase at step 535, and the new current settings applied before exiting the routine.
• a similar lower priority routine may be the ancillary task of detecting an open door, to allow load compensation or to allow some interaction with the person opening the door. While detection of the door opening may be by a pressure activated door switch it may equally well be by way of detection of a change in the loading on the evaporator fan motor within the beverage cooler, since this will alter as the air circulation alters on door opening. Thus a simple detection of a change in fan motor speed or current draw because of a different flow pattern can act to detect the opening of the beverage cooler door. Other conditions, such as vibration, may also be sensed and some specified action taken on the occurrence of unexpected values.
• interrupt-driven routines such as the above can be used to manage the time- critical tasks of operating a motor or motors, or of reading inputs, as each routine is designed to have a sufficiently small duration as not to noticeably impact the main system control loop.
• an accumulation of such interrupts may slow the control loop setting machine conditions in response to environment, customer use and motor conditions, it may be slowed by several orders of magnitude compared with its uninterrupted speed without affecting overall system performance, as the time constants in the overall system are of the order of minutes rather than milliseconds.
• control system allows other combinations of conditions to be checked, for instance a reduction in evaporator fan loading with time probably infers that the fan or evaporator needs cleaning, and an alert could be issued to warn of this.
• control system may take many forms provided that the control system provides for the control of any commutated motors as a first priority and responds to other inputs and control requirements as a lower priority.
• the controller of the invention is used in the control of the motors and ancillaries which are employed it the refrigeration industry.
• the present invention is therefore industrially applicable.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Mechanical Engineering (AREA)
• Thermal Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Devices That Are Associated With Refrigeration Equipment (AREA)

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• 2011
  • 2011-03-03 CN CN201180020643.7A patent/CN102869931B/zh not_active Expired - Fee Related
  • 2011-03-03 US US13/582,664 patent/US20130205807A1/en not_active Abandoned
  • 2011-03-03 WO PCT/NZ2011/000031 patent/WO2011108947A1/en active Application Filing
  • 2011-03-03 BR BR112012022453-0A patent/BR112012022453B1/pt active IP Right Grant
  • 2011-03-03 MX MX2012010282A patent/MX338483B/es active IP Right Grant
  • 2011-03-03 EP EP11750976.0A patent/EP2542842B1/en active Active

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