Phase change assisted heat sink
AssigneeBAE Systems Controls Inc.
InventorsTimothy Michael Grewe, Steve William Osovski
Life of this patent
Estimating the term…
Abstract
In an electric vehicle, the traction motor is driven from a battery by way of a controllable electric power switcher. In operation of the switcher, the power losses of the switches depends upon the power being handled; during acceleration the power is high, and at constant speed on level ground the power is small. Thus, the power “dissipated” by the switches varies with time. A cooler transfers heat from the switcher. During acceleration, the cooler may not be sufficient to limit the instantaneous switch temperature. A phase-change heat “sink” coupled to the switches absorbs heat from the switches during hard acceleration, and returns the heat to the cooler under more constant-speed conditions.
Claims5
A vehicle including
- an electric traction drive machine;
- a source of electrical energy;
- a controllable switching arrangement coupled to said traction drive machine and to said source of electrical energy, for coupling energy between said source of electrical energy and said motor under the control of control signals;
- operator-controlled control means coupled to said switching arrangement, for controlling the amount of energy coupled between said source and said machine by synthesizing a current waveform;
- a cooling system coupled to said controllable switching arrangement, for transferring heat from said switching arrangement to ambient;
- and
- a phase change energy transducer coupled to said cooling system and to said switching arrangement, for transiently absorbing heat generated by said switching arrangement in excess of that which said cooling system can instantaneously transfer.
An apparatus, comprising:
- an electrical machine [drive motor];
- a source of electrical energy;
- controllable switching means coupled to said machine [motor] and to said source of electrical energy, for providing energy to said machine [motor] from said source in an amount which varies with time, whereby the energy handled by said switching means varies with time, and the power-loss-generated heat in said switching means also varies with time;
- cooling means coupled to said switching means, for transferring said heat from said switching means to ambient, whereby the instantaneous temperature of said switching means tends to vary in response to the power being handled by said switching means;
- and
- phase change energy transducing means thermally coupled to said switching means and to said cooling means, for absorbing heat from said switching means when said instantaneous temperature of said switching means tends to rise, and for releasing heat to said cooling means when said instantaneous temperature of said switching means tends to fall, thereby tending to maintain said temperature of said switching means constant.
a vehicle, comprising:
- a drive wheel;
- a generator coupled to said wheel for generating electrical energy in response to braking;
- an electrical resistor coupled to said generator, for converting the electrical energy of braking into heat;
- and
- a phase change transducer thermally coupled to said resistor, for storing heat from resistor.
An apparatus, comprising:
- a drive motor:
- a source of electrical energy;
- controllable switching means coupled to said motor and to said source of electrical energy, for providing energy to said motor from said source in an amount which varies with time, whereby the energy handled by said switching means varies with time, and the power losses in said switching means also varies with time;
- cooling means coupled to said switching means, for transferring heat from said switching means to ambient, whereby the temperature of said switching means may vary depending upon the instantaneous power being handled;
- and
- phase change energy transducing means coupled to said switching means and to said cooling means, for temporarily changing phase and tending to maintain said temperature of said switching means constant.
Dependencies are inferred from the claim text.