Individual control of inner and outer Peltier elements
The present invention introduces a temperature calibrator arrangement, which comprises inner and outer Peltier elements as heating and cooling elements for the calibrator block. The arrangement comprises a first and second variable current or voltage source, and, in an embodiment, a first and second mechanical relay for switching polarities of the Peltier elements. The present invention controls the first and second current sources independently of one another. Furthermore, some methods are presented for getting rid of mechanical relay switchings while using the temperature calibrator during normal use, resulting in less clicking sounds and less physical wear as well.
1. A heating/cooling arrangement for a temperature calibrator, comprising:
a calibrator block, a processor circuit, heating and cooling elements, and a heatsink, wherein a single element configuration is used both for heating and cooling, wherein the heating/cooling arrangement comprises:
the heating and cooling elements comprising inner Peltier elements and outer Peltier elements with regard to the calibrator block, wherein the inner Peltier elements comprise elements both in the top and the bottom of the calibrator block, and the outer Peltier elements comprise elements both in the top and the bottom of the calibrator block, and all four Peltier element pairs are independently controllable by four independent driver channels;
a DC power supply;
wherein each inner and outer Peltier element are stacked with one another, respectively, and the arrangement further comprises:
a first variable current or voltage source and a second variable current or voltage source, configured to feed the inner and the outer Peltier elements, respectively; wherein
the first variable current or voltage source is controlled individually and independently of the second variable current or voltage source, by the processor circuit.
2. The arrangement according to claim 1 , wherein the first variable current or voltage source and the second variable current or voltage source are both bipolar.
3. The arrangement according to claim 1 , wherein the processor circuit is configured to set a ratio of the first variable current and the second variable current to an optimized value, wherein in order to reach the optimized value, the ratio is set substantially to 2:1 when heating the calibrator block.
4. The arrangement according to claim 1 , wherein the first variable current or voltage source and the second variable current or voltage source are both unipolar, and the arrangement further comprises:
a first mechanical relay selecting the polarity of the first current through the inner Peltier elements, and a second mechanical relay selecting the polarity of the second current through the outer Peltier elements, where
both first and second mechanical relays are independently controllable by the processor circuit.
5. The arrangement according to claim 1 , wherein the processor circuit is configured to set a ratio of the first variable current and the second variable current to an optimized value, wherein in order to reach the optimized value, the ratio is set substantially to 1:2 when cooling the calibrator block.
6. The arrangement according to claim 4 , wherein the processor circuit is configured to:
output from the second variable current or voltage source a relatively small and fixed positive current, resulting in a fixed temperature offset within the outer Peltier elements;
regulate temperature of the calibrator block by the inner Peltier elements, resulting in a negative current in the first variable current or voltage source for compensating the fixed temperature offset simultaneously with the regulation process,
resulting in continuously oppositely signed currents between the first and second variable current or voltage sources, leading to a lack of switchings in the mechanical relays.
7. The arrangement according to claim 4 , wherein the processor circuit is configured to:
let the outer Peltier elements to only perform heating;
let the inner Peltier elements to only perform cooling,
resulting in both currents from first and second variable current or voltage sources to not pass zero, leading to a lack of switchings in the mechanical relays.
8. The arrangement according to claim 4 , wherein the processor circuit is configured to:
output from the first variable current or voltage source a relatively small and fixed negative current, resulting in a first fixed temperature offset within the inner Peltier elements;
output from the second variable current or voltage source a relatively small and fixed positive current, resulting in a second fixed temperature offset within the outer Peltier elements;
regulate temperature of the calibrator block by both the inner Peltier elements and the outer Peltier elements,
resulting in the first and second fixed temperature offsets neutralizing one another at least partly, and
resulting in continuously oppositely signed currents between the first and second variable current or voltage sources, leading to a lack of switchings in the mechanical relays.
9. A method for controlling a heating/cooling arrangement for a temperature calibrator, the arrangement comprising a calibrator block, a processor circuit, heating and cooling elements, a heatsink and a DC power supply, wherein the heating and cooling elements comprise inner Peltier elements and outer Peltier elements with regard to the calibrator block, wherein each inner and outer Peltier element are stacked with one another, respectively, and the method comprises the following steps of:
applying a single element configuration used both for heating and cooling;
feeding a first variable current or voltage from a first variable current or voltage source into the inner Peltier elements;
feeding a second variable current or voltage from a second variable current or voltage source into the outer Peltier elements; and
controlling, by the processor circuit, the first variable current or voltage source individually and independently of the second variable current or voltage source,
wherein the inner Peltier elements comprise elements both in the top and the bottom of the calibrator block, and the outer Peltier elements comprise elements both in the top and the bottom of the calibrator block, and all four Peltier element pairs are independently controllable by four independent driver channels.
10. A non-transitory computer readable medium for controlling a heating/cooling arrangement for a temperature calibrator, the arrangement comprising a calibrator block, a processor circuit, heating and cooling elements, a heatsink and a DC power supply, wherein the heating and cooling elements comprise inner Peltier elements and outer Peltier elements with regard to the calibrator block, wherein each inner and outer Peltier element are stacked with one another, respectively, the non-transitory computer readable medium having program code stored thereon that, in response to execution by the processor circuit, causes the processor circuit to perform the steps of:
feeding a first variable current or voltage from a first variable current or voltage source into the inner Peltier elements;
feeding a second variable current or voltage from a second variable current or voltage source into the outer Peltier elements; and
controlling, by the processor circuit, the first variable current or voltage source individually and independently of the second variable current or voltage source,
wherein the inner Peltier elements comprise elements both in the top and the bottom of the calibrator block, and the outer Peltier elements comprise elements both in the top and the bottom of the calibrator block, and all four Peltier element pairs are independently controllable by four independent driver channels.