ELECTRIC HEATING DEVICE AND METHOD FOR OPERATING THE ELECTRIC HEATING DEVICE

Abstract

An electric heating device having a multiplicity of electric heating elements, wherein the respective electric heating element has a first electric contact element and a second electric contact element and at least one heater, wherein the first and second electric contact elements achieve electrical contacting of the at least one electric heater, additionally having a first voltage connection element and a second voltage connection element, additionally having first switching elements and having second switching elements, wherein pairs of two electric heating elements are each wired such that two first electric contact elements in each case of the two electric heating elements can be switchably connected to the first voltage connection element by one of the first switching elements and one of the second contact elements in each case of the pairs can be switchably connected to the second voltage connection element by means of a second switching element.

Claims

1. An electric heating device comprising: a plurality of electric heating elements, each of the plurality of electric heating elements have a first electric contact element and a second electric contact element and at least one heater, the first and second electric contact elements electrically contacting the at least one electric heater; a first voltage connection element and a second voltage connection element; and first switching elements and second switching elements, wherein pairs of two electric heating elements are each wired such that two first electric contact elements of the two electric heating elements are adapted to be switchably connected to the first voltage connection element by one of the first switching elements, and wherein one of the second contact elements of the pairs of the two electric heating elements are adapted to be switchably connected to the second voltage connection element via a second switching element, and the other second contact element of the pair is adapted to be switchably connected thereto by a different second switching element.

2. The electric heating device according to claim 1, wherein each first heating element of the two heating elements of the pairs are adapted to be switchably connected by its second contact element through one second switching element to the second voltage connection element and each second heating element of the two heating elements of the pairs is adapted to be switchably connected by its second contact element through the other second switching element to the second voltage connection element.

3. The electric heating device according to claim 1, wherein a third heating element is associated with the pairs having two electric heating elements so that triplets of heating elements are present, wherein the triplets of three electric heating elements are each wired such that three first electric contact elements of the three electric heating elements are adapted to be switchably connected to the first voltage connection element by one of the first switching elements and one of the second contact elements of the triplets is adapted to be switchably connected to the second voltage connection element via a first second switching element, wherein a second second contact element of the triplets is adapted to be switchably connected thereto by a second second switching element, and wherein a third second contact element of the triplets is adapted to be switchably connected thereto by a third second switching element.

4. The electric heating device according to claim 3, wherein each first heating element of the three heating elements of the triplets is adapted to be switchably connected by its second contact element through one second switching element to the second voltage connection element, and each second heating element of the three heating elements of the triplets is adapted to be switchably connected by its second contact element through the second second switching element to the second voltage connection element, and each third heating element of the three heating elements of the triplets is adapted to be switchably connected by its second contact element through the third second switching element to the second voltage connection element.

5. The electric heating device according to claim 1, wherein N−2 heating elements are associated with the pairs having two electric heating elements so that N-tuples of heating elements are present, wherein the N-tuples of N electric heating elements are each wired such that N first electric contact elements of the N electric heating elements are adapted to be switchably connected by one of the first switching elements to the first voltage connection element, and wherein one first second contact element of the N-tuples is adapted to be switchably connected to the second voltage connection element via a first second switching element, and wherein a second second contact element of the N-tuples is adapted to be switchably connected thereto by a second second switching element, and wherein a third second contact element of the N-tuples is adapted to be switchably connected thereto by a third second switching element, and wherein an nth second contact element of the N-tuples is adapted to be switchably connected thereto by an nth second switching element, and wherein an N−1th second contact element of the N-tuples is adapted to be switchably connected thereto via an N−1th second switching element, and wherein an Nth second contact element of the N-tuples is adapted to be switchably connected thereto via an Nth second switching element, and wherein N is a natural number that is greater than or equal to 2 and n is a natural number from 4 to N−2.

6. The electric heating device according to claim 5, wherein each first heating element of the N heating elements of the N-tuples is adapted to be switchably connected by its second contact element through the first second switching element to the second voltage connection element, and wherein each second heating element of the N heating elements of the N-tuples is adapted to be switchably connected by its second contact element through the second second switching element to the second voltage connection element, and each third heating element of the N heating elements of the N-tuples is adapted to be switchably connected by its second contact element through the third second switching element to the second voltage connection element, and each N−1th heating element of the N heating elements of the N-tuples are adapted to be switchably connected by its second contact element through the N−1th second switching element to the second voltage connection element, and each Nth heating element of the N heating elements of the N-tuples is adapted to be switchably connected by its second contact element through the Nth second switching element to the second voltage connection element, and wherein N is a natural number that is greater than or equal to 2.

7. The electric heating device according to claim 1, wherein the electric switching elements are electronically controllable switching elements.

8. The electric heating device according to claim 7, wherein the electric switching elements are electronically controllable power switching elements.

9. The electric heating device according to claim 7, wherein the electric switching elements are part of an electronic control unit that is a component of the electric heating device.

10. The electric heating device according to claim 1, wherein radiator elements are provided and are arranged in thermal contact with the electric heating elements for heat transfer from the electric heating elements to a medium flowing around and/or through the radiator elements.

11. The electric heating device according to claim 1, wherein the radiator elements are arranged such that at least one radiator element is arranged adjacent to one of the electric heating elements.

12. A method for operating an electric heating device according to claim 1, the method comprising: selectively controlling the first switching elements; and selectively controlling the second switching elements; wherein the first and second switching elements are selectively controlled in order to heat the electric heating elements in a controlled manner.

13. The method according to claim 12, wherein the first switching elements and/or the second switching elements are controlled in order to heat each heating element in an individually controlled manner.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:

[0027] FIG. 1 shows a schematic representation of an electric heating device according to the invention,

[0028] FIG. 2 shows a graph for explaining the invention; and

[0029] FIG. 3 shows a schematic representation of another electric heating device according to the invention.

DETAILED DESCRIPTION

[0030] FIG. 1 shows a schematic representation of an electric heating device 1. The electric heating device 1 can preferably be used as a heater or as an auxiliary heater for a motor vehicle, including for an electric vehicle, in particular. The electric heating device 1 can be intended for heating air, for example for the motor vehicle interior.

[0031] The electric heating device 1 has a multiplicity of electric heating elements 2. These heating elements 2 can be arranged in a plane of a heating grid, for example, or otherwise.

[0032] Each one of the electric heating elements 2 in this design has a first electric contact element 3, a second electric contact element 4, and at least one heater 5. Multiple such heater 5 can also be provided in this design. The one or more heater 5 is or are contacted in parallel by the first contact element 3 and the second contact element 4, depending on how many heater 5 are provided. The heater 5 can be designed as PTC elements, for example. Alternatively, they can also be designed as resistance elements with an NTC characteristic.

[0033] The first and second electric contact elements 3, 4 in this design achieve electrical contacting of the at least one electric heater 5 or of the multiple electric heater 5 of a heating element 2.

[0034] Furthermore, the electric heating device 1 has a first voltage connection element 6 and a second voltage connection element 7 that serve to connect the electric heating element 2 to an external voltage source. In this design, the first voltage connection element 6 is connected to a first electric potential and the second voltage connection element 7 is connected to a second electric potential so that the electric heating device 1 is connected to a potential difference.

[0035] Furthermore, the electric heating device 1 has first switching elements S11, S12, S13, and S14 as well as second switching elements S21 and S22. The first switching elements S11 to S14 electrically connect the heating elements 2 to the first voltage connection element 6, and the second switching elements S21 and S22 electrically connect the heating elements 2 to the second voltage connection element 7. The type of electrical connection is explained below.

[0036] FIG. 2 shows that pairs of two electric heating elements 2 are each wired such that the two first electric contact elements 3 in each case of the two electric heating elements 2 of a given pair can be switchably connected to the first voltage connection element 6 by one of the first switching elements S11, S12, S13, S14, and, additionally, one of the second contact elements 4 in each case of the pairs can be switchably connected to the second voltage connection element 7 by means of a second switching element S21 and the other second contact element 4 in each case of the pair can be switchably connected thereto by a different second switching element S22.

[0037] This achieves the result that all individual heating elements 2 can be individually powered, for example in PWM control, through appropriate actuation and opening or closing of the individual switching elements of the individual switching elements S11 to S22.

[0038] For this purpose, each first heating element 2 of the two heating elements 2 of the pairs can be switchably connected by its second contact element 4 through one second switching element S21 to the second voltage connection element 7, and each second heating element 2 of the two heating elements 2 of the pairs can be switchably connected by its second contact element 4 through the other second switching element S22 to the second voltage connection element 7, for example.

[0039] The electric switching elements S11 to S22 can be electronically controllable switching elements, for example electronically controllable power switching elements.

[0040] According to one advantageous exemplary embodiment, the electric switching elements S11 to S22 are part of an electronic control unit that is a component of the electric heating device 1.

[0041] In the case of the electric heating device 1, it is additionally advantageous when radiator elements 8 are provided that are arranged in thermal contact with the electric heating elements 2 in order to promote the heat transfer from the electric heating elements 2 to a medium flowing around and/or through the radiator elements 8.

[0042] The radiator elements 8 are arranged such that at least one radiator element 8 is arranged adjacent to one of the electric heating elements 2 in each case, as FIG. 1 shows by way of example.

[0043] Alternatively, the radiator elements 8 can also be arranged in another way and/or additional elements for airflow control can also be provided.

[0044] An electric heating device 1 shown in FIG. 1 permits a method for operating an electric heating device 1 in such a manner that the first switching elements S11 to S14 and the second switching elements S21 and S22 are selectively controlled in order to heat the electric heating elements 2 in a controlled manner. In this case the respective switching elements S11 to S22 are controlled together or in alternation or singly in such a manner that individual heating elements 2 are selectively heated, for example through PWM control of the current flowing through the heater 5. Thus, sequential heating of the heating elements 2 can be carried out by means of PWM control, for example.

[0045] Accordingly, the first switching elements S11 to S14 and/or the second switching elements S21 and S22 are controlled in order to heat each heating element in an individually controlled manner.

[0046] FIG. 2 shows a graph for explaining the control method. The current flow I is shown here as a function of time t.

[0047] From time t0 to t1, switch S11 is closed and switches S12 to S14 are open. Furthermore, switch S21 is closed and switch S22 is open. A current thus flows through the first heating element 2 from the left as seen in FIG. 1. From t1 to t2, switch S11 and/or switch S21 is also open, so no current flows.

[0048] From time t2 to t3, switch S11 is closed and switches S12 to S14 are open. Furthermore, switch S22 is closed and switch S21 is open. A current thus flows through the second heating element 2 from the left as seen in FIG. 1. From t3 to t4, switch S11 and/or switch S22 is also open, so no current flows.

[0049] From time t4 to t5, switch S12 is closed and switches S11, S13, and S14 are open. Furthermore, switch S21 is closed and switch S22 is open. A current thus flows through the third heating element 2 from the left as seen in FIG. 1. From t5 to t6, switch S12 and/or switch S21 is also open, so no current flows.

[0050] From time t6 to t7, switch S12 is closed and switches S11, S13, and S14 are open. Furthermore, switch S22 is closed and switch S21 is open. A current thus flows through the fourth heating element 2 from the left as seen in FIG. 1. From t7 to t8, switch S12 and/or switch S22 is also open, so no current flows.

[0051] From time t8 to t9, switch S13 is closed and switches S11, S12, and S14 are open. Furthermore, switch S21 is closed and switch S22 is open. A current thus flows through the fifth heating element 2 from the left as seen in FIG. 1. From t9 to t10, switch S13 and/or switch S21 is also open, so no current flows.

[0052] From time t10 to t11, switch S13 is closed and switches S11, S12, and S14 are open. Furthermore, switch S22 is closed and switch S21 is open. A current thus flows through the sixth heating element 2 from the left as seen in FIG. 1. From t11 to t12, switch S13 and/or switch S22 is also open, so no current flows.

[0053] From time t12 to t13, switch S14 is closed and switches S11, S12, and S13 are open. Furthermore, switch S21 is closed and switch S22 is open. A current thus flows through the seventh heating element 2 from the left as seen in FIG. 1. From t13 to t14, switch S14 and/or switch S21 is also open, so no current flows.

[0054] From time t14 to t15, switch S14 is closed and switches S11, S12, and S13 are open. Furthermore, switch S22 is closed and switch S21 is open. A current thus flows through the eighth heating element 2 from the left as seen in FIG. 1. From t15 to t16, switch S14 and/or switch S22 is also open, so no current flows.

[0055] In this way, all heating elements 2 can be controlled. It is then possible to implement PWM control, for example, over the time of controlled current flow.

[0056] FIG. 3 shows a schematic representation of another electric heating device 1 according to the invention. The electric heating device 1 can preferably be used as a heater or as an auxiliary heater for a motor vehicle, including for an electric vehicle, in particular. The electric heating device 1 can be intended for heating air, for example for the motor vehicle interior.

[0057] The electric heating device 1 has a multiplicity of electric heating elements 2. These heating elements 2 can likewise be arranged in a plane of a heating grid, for example, or otherwise.

[0058] Each one of the electric heating elements 2 in this design has a first electric contact element 3, a second electric contact element 4, and at least one heater 5. Multiple such heater 5 can also be provided in this design. The one or more heater 5 is or are contacted in parallel by the first contact element 3 and the second contact element 4, depending on how many heater 5 are provided. The heater 5 can be designed as PTC elements, for example. Alternatively, they can also be designed as resistance elements with an NTC characteristic.

[0059] The first and second electric contact elements 3, 4 in this design achieve electrical contacting of the at least one electric heater 5 or of the multiple electric heater 5 of a heating element 2.

[0060] Furthermore, the electric heating device 1 has a first voltage connection element 6 and a second voltage connection element 7 that serve to connect the respective electric heating element 2 to an external voltage source. In this design, the first voltage connection element 6 is connected to a first electric potential and the second voltage connection element 7 is connected to a second electric potential so that the electric heating device 1 is connected to a potential difference, for example to a battery.

[0061] Furthermore, the electric heating device 1 has first switching elements S11, S12, and S13 as well as second switching elements S21, S22, and S23. The first switching elements S11 to S13 electrically connect the heating elements 2 to the first voltage connection element 6 and the second switching elements S21, S22, and S23 electrically connect the heating elements 2 to the second voltage connection element 7. The type of electrical connection is explained below.

[0062] For this purpose, the first electric contact elements 3 of the electric heating elements 2 of first triplets are connected in each case through the first switching element S11 to the first voltage connection element 6. Furthermore, the first electric contact elements 3 of the electric heating elements 2 of second triplets are connected in each case through the first switching element S12 to the first voltage connection element 6. Furthermore, the first electric contact elements 3 of the electric heating elements 2 of third triplets are connected in each case through the first switching element S13 to the first voltage connection element 6.

[0063] Control of the electric heating device 1 is carried out in such a manner that all individual heating elements 2 can be individually powered, for example in PWM control, through appropriate actuation and opening or closing of the individual switching elements S11 to S23.

[0064] For this purpose, for example, each first heating element 2 of the three heating elements 2 of the triplets of zone 1, zone 2, and zone 3 can be switchably connected by its second contact element 4 through one second switching element S21 to the second voltage connection element 7, and each second heating element 2 of the three heating elements 2 of the triplets can be switchably connected by its second contact element 4 through the second second switching element S22 to the second voltage connection element 7. Also, each third heating element 2 of the three heating elements 2 of the triplets can be switchably connected by its second contact element 4 through a third second switching element S23 to the second voltage connection element 7.

[0065] According to one advantageous exemplary embodiment, the electric switching elements S11 to S23 are electronically controllable switching elements, for example electronically controllable power switching elements.

[0066] According to one advantageous exemplary embodiment, the electric switching elements S11 to S23 are part of an electronic control unit that is a component of the electric heating device 1.

[0067] In the case of the electric heating device 1, it is additionally advantageous when radiator elements 8 are provided that are arranged in thermal contact with the electric heating elements 2 in order to promote heat transfer from the electric heating elements 2 to a medium flowing around and/or through the radiator elements 8.

[0068] According to one exemplary embodiment, the radiator elements 8 are arranged such that at least one radiator element 8 is arranged adjacent to one of the electric heating elements 2 in each case, as FIG. 3 shows by way of example. Alternatively, the radiator elements 8 can also be arranged in another way and/or additional elements for airflow control can also be provided.

[0069] An electric heating device 1 shown in FIG. 3 permits a method for operating an electric heating device 1 in such a manner that the first switching elements S11 to S13 and the second switching elements S21, S22, and S23 are selectively controlled in order to heat the electric heating elements 2 in a controlled manner. In this case the respective switching elements S11 to S23 are controlled together or in alternation or singly in such a manner that individual heating elements 2 are selectively heated, for example through PWM control of the current flowing through the heater 5. Thus, sequential heating of the heating elements 2 can be carried out by means of PWM control, for example.

[0070] Accordingly, the first switching elements S11 to S13 and/or the second switching elements S21, S22, and S23 are controlled in order to heat each heating element in an individually controlled manner.

[0071] The electric heating device 1 from FIG. 3 can also be understood such that a third heating element 2 is associated with each of the pairs having two electric heating elements 2 so that triplets of electric heating elements 2 are present, wherein the triplets of three electric heating elements 2 are each wired such that three first electric contact elements 3 of the three electric heating elements 2 in each case can be switchably connected through one of the first switching elements S11, S12, S13 to the first voltage connection element 6, and one of the second contact elements 4 of the triplets in each case can be switchably connected to the second voltage connection element 7 by means of a first second switching element S21, and a second second contact element 4 of the triplets in each case can be switchably connected thereto by a second second switching element S22, and a third second contact element 4 of the triplets in each case can be switchably connected thereto by a third second switching element S23.

[0072] Accordingly, each first heating element 2 of the three heating elements 2 of the triplets can be switchably connected by its second contact element 4 through one second switching element S21 to the second voltage connection element 7, and each second heating element 2 of the three heating elements 2 of the triplets can be switchably connected by its second contact element 4 through the second second switching element S22 to the second voltage connection element 7, and each third heating element 2 of the three heating elements 2 of the triplets can be switchably connected by its second contact element 4 through the third second switching element S23 to the second voltage connection element 7.

[0073] In the most general sense, this can also be phrased such that N−2 heating elements are associated with the pairs having two electric heating elements, so that N-tuples of heating elements are present, wherein the N-tuples of N electric heating elements 2 are each wired such that N first electric contact elements 3 of the N electric heating elements 2 in each case can be switchably connected through one of the first switching elements S11, S12, S13, S14, . . . to the first voltage connection element 6, and one first second contact element 4 of the N-tuples in each case can be switchably connected to the second voltage connection element 7 by means of a first second switching element S21, S22, S23, . . . S2N−1, S2N, and a second second contact element 4 of the N-tuples in each case can be switchably connected thereto by a second second switching element S21, S22, S23, . . . , S2N−1, S2N, and a third second contact element 4 of the N-tuples in each case can be switchably connected thereto by a third second switching element S21, S22, S23, . . . , S2N−1, S2N, and an N−1th second contact element 4 of the N-tuples in each case can be switchably connected thereto by means of an N−1th second switching element S21, S22, S23, . . . , S2N−1, S2N, and an Nth second contact element 4 of the N-tuples in each case can be switchably connected thereto by means of an Nth second switching element S21, S22, S23, . . . , S2N−1, S2N, wherein N is a natural number that is greater than or equal to 2.

[0074] Accordingly, each first heating element 2 of the N heating elements 2 of the N-tuples can be switchably connected by its second contact element 4 through the first second switching element S21, S22, S23, . . . , S2N−1, S2N to the second voltage connection element 7, and each second heating element 2 of the N heating elements 2 of the N-tuples can be switchably connected by its second contact element 4 through the second second switching element S21, S22, S23, . . . , S2N−1, S2N to the second voltage connection element 7, and each third heating element 2 of the N heating elements 2 of the N-tuples can be switchably connected by its second contact element 4 through the third second switching element S21, S22, S23, . . . , S2N−1, S2N to the second voltage connection element 7, etc., etc., and each N−1th heating element 2 of the N heating elements 2 of the N-tuples can be switchably connected by its second contact element 4 through the N−1th second switching element S21, S22, S23, S2N−1, S2N to the second voltage connection element 7, and each Nth heating element 2 of the N heating elements 2 of the N-tuples can be switchably connected by its second contact element 4 through the Nth second switching element S21, S22, S23, . . . , S2N−1, S2N to the second voltage connection element 7, wherein N is a natural number that is greater than or equal to 2.

[0075] The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.