Power supply for refrigeration units
First Claim
1. In a refrigeration system, the combination comprising a refrigeration unit having a refrigerated enclosure and a compressor driven by an AC motor, a battery, inverter circuit means responsive to connection to said battery to supply first AC power to said motor, connection means for connection to a source of second AC power, first switch means operatively connected to said AC power connection means, said inverter circuit means and said motor, said first switch means having a first switch position for connecting said compressor motor to said inverter circuit means and a second switch position for connecting said compressor motor to said AC power connection means, battery charging means electrically connected to said AC power connection means and adapted to be responsive to said second AC power to provide a series of pulses for charging said battery, second switch means operable in unison with said first switch means and having third and fourth switch positions corresponding to said first and second switch positions of said first switch means, said third switch position of said second switch means being arranged to connect said battery to said inverter circuit means to enable said inverter circuit means, said fourth switch position being arranged to connect said battery to said battery charging means to enable said battery charging means according to the charge on said battery, and third switch means responsive to a predetermined condition of said refrigeration unit to remove power from said compressor motor regardless of the switch positions of said first and second switch means.
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Accused Products
Abstract
A battery powered inverter power supply for recreational vehicle refrigeration units or the like which is adapted to operate in a DC mode wherein power is supplied to the inverter and refrigeration unit from a vehicle battery, and in an AC mode wherein power is supplied to the refrigeration unit from a source of normal household power. A cold control circuit is responsive to a thermostatic sensor within the refrigerated enclosure to apply battery power to the inverter power supply only when the supply is operating in the DC mode and cooling is required. A battery charger is operable during the AC mode to automatically recharge the vehicle battery.
61 Citations
32 Claims
- 1. In a refrigeration system, the combination comprising a refrigeration unit having a refrigerated enclosure and a compressor driven by an AC motor, a battery, inverter circuit means responsive to connection to said battery to supply first AC power to said motor, connection means for connection to a source of second AC power, first switch means operatively connected to said AC power connection means, said inverter circuit means and said motor, said first switch means having a first switch position for connecting said compressor motor to said inverter circuit means and a second switch position for connecting said compressor motor to said AC power connection means, battery charging means electrically connected to said AC power connection means and adapted to be responsive to said second AC power to provide a series of pulses for charging said battery, second switch means operable in unison with said first switch means and having third and fourth switch positions corresponding to said first and second switch positions of said first switch means, said third switch position of said second switch means being arranged to connect said battery to said inverter circuit means to enable said inverter circuit means, said fourth switch position being arranged to connect said battery to said battery charging means to enable said battery charging means according to the charge on said battery, and third switch means responsive to a predetermined condition of said refrigeration unit to remove power from said compressor motor regardless of the switch positions of said first and second switch means.
- 16. In a refrigeration system, the combination comprising a refrigeration unit having a refrigerated enclosure and a compressor driven by an AC induction motor, a source of DC power, inverter circuit means including triggering circuit means responsive to connection to said DC power source to supply a series of periodic triggering signals and inverter switching means operatively connected to said DC power source and responsive to said triggering signals to provide AC power to said induction motor, said inverter switching means drawing substantially no power from said DC power source in the absence of said triggering signals, and control circuit means operatively connecting said DC power source to said triggering circuit means and responsive to a predetermined condition of said refrigeration system to disconnect said DC power source from said triggering circuit means, said control circuit means comprising first switching means having a conductive condition responsive to said predetermined condition of said refrigeration system, a control circuit operatively connected to said first switching means to supply a control signal in response to the conductive condition of said first switching means, and second switching means comprising a first electronic switch having first and second electrodes electrically connecting said DC power source and to said triggering circuit means and a control electrode responsive to said control signal to change the conductive condition of said first electronic switch.
- 22. In a refrigeration system, the combination comprising a refrigeration unit having a compressor driven by an AC motor, a battery which provides a source of DC power, inverter circuit means responsive to connection to said battery to supply first AC power to said motor from said battery, said inverter circuit means including rectifier means and a transformer having a primary winding connected in series with said rectifier means across said battery and having a secondary winding connected to said motor, AC power input means connected to said motor and to said secondary and adapted for connection to a source of second AC power so that when said AC power input means is connected to said AC source said second AC power is applied to said motor and to said secondary winding thereby inducing an AC signal in said primary, said rectifier means being arranged to rectify said induced AC signal and develop DC power for charging said battery, regulating means connected to said battery and responsive to the charge level thereof to provide a first signal, and switch means connected between said AC power input means and said transformer secondary and responsive to said first digital to place said second AC power across said secondary when said charge level of said battery is below a first predetermined level, said switch means comprising an electronic switch having a control electrode, and first and second main electrodes respectively electrically connected to said AC power input means and to said secondary winding, the conductive condition between said first and second electrodes being responsive to a triggering signal at said control electrode, and triggering means responsive to said first signal to provide said triggering signal when said charge level is below said first predetermined level.
- 25. In a refrigeration system, the combination comprising a refrigeration unit having a compressor driven by an AC motor, a battery which provides a source of DC power, inverter circuit means responsive to connection to said battery to supply first AC power to said motor from said battery, said inverter circuit means including rectifier means and a transformer having a primary winding connected in series with said rectifier means across said battery and having a secondary winding connected to said motor, AC power input means connected to said motor and to said secondary and adapted for connection to a source of second AC power so that when said AC power input means is connected to said AC source said second AC power is applied to said motor and to said secondary winding thereby inducing an AC signal in said primary, said rectifier means being arranged to rectify said induced AC signal and develop DC power for charging said battery, regulating means connected to said battery and responsive to the charge level thereof to provide a first signal, and switch means connected between said AC power input means and said transformer secondary and responsive to said first signal to place said second AC power across said secondary when said charge level of said battery is below a first predetermined level, said regulating means providing said first signal when said battery reaches said first predetermined minimum charge level and maintaining said first signal until said charge level rises to a second predetermined level higher than said first level.
- 28. In a refrigeration system, the combination comprising a refrigeration unit having a compressor driven by an AC motor, a source of DC power, inverter circuit means responsive to connection to said DC power source to supply first AC power to said motor, AC power input means adapted for connection to a source of second AC power, first switch means having first and second switch positions, said first switch means selectively connecting said compressor motor directly to said inverter circuit means and to said AC power input means in said first and second switch positions respectively, second switch means operatively coupled to said first switch means, said second switch means connecting said DC power source to said inverter circuit means when said first switch means is in said first switch position, and sensing means electrically coupled to said AC power input means to sense connection thereof to said AC power source, said sensing means being in a first conductive condition when said AC power input means is disconnected from said AC power source and in a second conductive condition when said AC power input means is connected to said AC source, and wherein said first and second switch means are operatively connected to said sensing means such that said first and second switch means are in said first and third switch positions, respectively, when said sensing means is in said first condition and in said second and fourth switch positions, respectively, when said sensing means is in said second condition.
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32. In a refrigeration system, the combination comprising a refrigeration unit having a compressor driven by an AC motor, a source of DC power, inverter circuit means responsive to connection to said DC power source to supply first AC power to said motor, AC power input means adapted for connection to a source of second AC power, said inverter circuit means including reactive output coupling means electrically isolating said inverter circuit means against direct electrical conduction between said inverter circuit means and said AC power input means and against direct electrical conduction between said inverter circuit means and said compressor motor, first switch means having first and second switch positions, said first switch means selectively connecting said compressor motor to said inverter circuit means and to said AC power input means in said first and second switch positions, respectively, second switch means operatively coupled to said first switch means, said second switch means connecting said DC power source to said inverter circuit means when said first switch means is in said first switch position, and third switch means responsive to a predetermined condition of said refrigeration unit to remove power from said compressor motor regardless of the switch positions of said first and second switch means, said third switch means including reactive coupling means electrically isolating said third switch means against direct electrical conduction between said third switch means and said source of AC power and against direct electrical conduction between said third switch means and said motor.
Specification