Glass panel apparatus and method for controlling the glass panel apparatus

Abstract

Switchable glass panel (4) and control voltage (U A A glass panel arrangement (2) is provided having a control unit (6) for controlling the switchable glass panel (4) with a control voltage (U A ) is composed of a first AC voltage signal (S1) and a second AC voltage signal (S2), the first AC voltage signal (S1) being phase shifted 180° with respect to the second AC voltage signal (S2). The control unit (6) comprises a first analog amplifier (8) for amplifying the first AC voltage signal (S1) with two first power switches (T1, T2) and a second analog amplifier (10) for amplifying the second AC voltage signal (S2) with two second power switches (T3, T4), one power switch (T1, T3) of each of the two analog amplifiers (8, 10) together forming an upper voltage circuit (12) and the other power switch (T2, T4) of each of the two analog amplifiers (8, 10) together forming a lower voltage circuit (14).

Description

Technical Field

[0001] The present invention relates to a glass panel device, a method for controlling a glass panel device, and a motor vehicle having a glass panel device.

Background Art

[0002] Switchable glass or smart glass (e.g., LC, PDLC, or SPD) is a film that can change its optical properties from transparent to opaque and vice versa when an AC (alternating current) voltage is applied. Such films are used, for example, in the form of glass windows of buildings or motor vehicles, such as glass roofs, where the states of being transparent, i.e., translucent, and opaque, i.e., light-blocking, are required or desired by customers.

[0003] Depending on the technology, switchable glass is typically controlled by a sinusoidal voltage of 20V - AC to 180V - AC. Thus, other AC voltage curves are also possible. If only the "switch - on" (e.g., opaque) and "switch - off" (e.g., transparent) states are required, a transformer with a corresponding voltage transformation ratio may be used for connection to a 240V - AC network.

[0004] When an AC voltage is generated from a DC (direct current) voltage, as in the case of a motor vehicle for example, an inverter is required. This can be realized, inter alia, using the following circuits. - Bridge circuit (full - bridge) - Class - D amplifier, or - Analog amplifier

[0005] Bridge circuits in full-bridge configuration are easy to implement. However, the rectangular voltage curve provided by a full bridge has the disadvantage of generating high-frequency EMC interference in cables and foils. To avoid this, for example, a reasonably large LC filter is required. In addition, relatively high-voltage digital switching generates EMC interference in existing PCBs. For this reason, a metal housing for shielding may be necessary.

[0006] Class D amplifiers are used, for example, in audio amplifiers. They are digital half-bridges controlled by pulse-width modulated signals. However, high-frequency EMC interference can occur here as well. For this reason, LC filters and sometimes metal housings are typically required for shielding, making the overall design cost-intensive and complex.

[0007] Control using analog amplifiers is described, for example, in German patent application 102016214292A1. Control using analog amplifiers does not generate high-frequency EMC interference. However, this type of control involves relatively large power losses. Therefore, extensive cooling is required. [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] Based on this, the present invention aims to provide a glass panel device that does not generate EMC interference and reduces power loss, and a method for controlling the glass panel device. [Means for solving the problem]

[0009] With respect to glass panel devices, according to the present invention, the objective is solved by a glass panel device having the features of claim 1. With respect to methods, according to the present invention, the objective is solved by a method for controlling a glass panel device having the features of claim 7.

[0010] Advantageous embodiments, further developments, and variations are the subject of the dependent claims. The advantages and preferred embodiments described with respect to glass panel devices are equally applicable to methods, and vice versa.

[0011] Specifically, the underlying purpose of the glass panel apparatus is solved by a glass panel apparatus having a switchable glass panel and a control unit for controlling the switchable glass panel with a control voltage. The control voltage consists of a first AC voltage signal and a second AC voltage signal, the first AC voltage signal being electrically phase-shifted by 180° relative to the second AC voltage signal.

[0012] Furthermore, the control unit includes a first analog amplifier having two first power transistors for amplifying a first AC voltage signal, and a second analog amplifier having two second power transistors for amplifying a second AC voltage signal. The power transistors may be designed, for example, as MOSFETs, or alternatively, as bipolar transistors. One power transistor of each of the two analog amplifiers together forms an upper voltage circuit. In other words, the upper voltage circuit is formed by one of the two power transistors of the first analog amplifier and one of the two power transistors of the second analog amplifier. Similarly, the other power transistor of the two analog amplifiers together forms a lower voltage circuit.

[0013] A switchable glass panel is further connected between the output of the first analog amplifier and the output of the second analog amplifier. As a result, the negative supply voltage can be eliminated.

[0014] By using an analog amplifier, the EMC interference mentioned at the beginning can be avoided. As a result, the expensive metal housing for shielding can be eliminated, making it possible to use a cost-effective plastic housing. Furthermore, additional filter components are not required, which also provides cost and design advantages.

[0015] The control unit further includes a first voltage regulator configured to apply a variable supply voltage to the upper voltage circuit. As a result, the supply voltage can be reduced accordingly in the region between the peaks of the sinusoidal control signal. This optimized supply voltage can reduce power loss in the upper voltage circuit by, for example, about 30% compared to a conventional analog amplifier circuit. When percentage data regarding power loss savings / reductions are specified below, these data are always in comparison to a conventional analog amplifier circuit with a sinusoidal output voltage.

[0016] According to an alternative embodiment, the control unit has a discharge unit connected between the output of the first analog amplifier and the output of the second analog amplifier. As a result, the switchable glass panel can be discharged at half the control voltage, thereby reducing power loss by approximately 50% compared to known conventional analog amplification circuits. To realize the discharge circuit, for example, a bipolar transistor or MOSFET can be used. This type of switching element is available on the market in a wide variety of modifications and configurations, and as a result, the discharge unit can be implemented by simple means, and can be optimally adapted with respect to the power parameters of the glass panel device.

[0017] The above configuration can reduce power loss by up to 65% compared to known analog amplification circuits. The minimization of power loss with the above configuration will be explained again in the context of the diagram description using a specific example. Specifically, by using a MOSFET in the analog amplifier and skillfully generating the signal form of the AC voltage signal, additional components of the discharge circuit can be omitted, which also has a favorable impact on the structure of the glass panel device.

[0018] In one advanced configuration, the control unit further includes a second voltage regulator configured to apply a variable supply voltage to the lower voltage circuit. Similar to the application of a variable supply voltage to the upper voltage circuit, a variable voltage source is also supplied to the lower voltage circuit. As a result, a further reduction of approximately 15% in power loss can be achieved.

[0019] In one embodiment, the second voltage regulator includes a switch, a diode, and a comparator. Particularly in the case of automobiles, the supplied voltage is usually about 12-13V, so the second voltage regulator can be easily implemented with the above-mentioned components, and as a result the "lower supply voltage," i.e., the supply voltage of the lower voltage circuit, is alternately switched between ground and the vehicle voltage. This control is performed by the comparator. Furthermore, while the power transistor of the second voltage regulator is open, current flows back to the vehicle battery during operation. As a result, the total power can be further reduced.

[0020] The configuration described above can save approximately 7% of power loss on its own (based on unoptimized power loss) with minimal cost. The maximum savings are approximately 70% (based on unoptimized power loss).

[0021] Further reduction of power loss ensures that the control of the switchable glass panel functions without error even at temperatures up to 105°C. This "temperature tolerance" is particularly important when the switchable glass panel is used as a vehicle roof, as such temperature values ​​can occur in automotive components, especially during the summer. In one embodiment, the power transistors of the first analog amplifier and the power transistors of the second analog amplifier are formed as bipolar transistors or MOSFETs. The advantage of this configuration is that this type of component is available in various modifications, and therefore the analog amplifier can be easily and optimally adapted or configured to meet specific requirements.

[0022] In one embodiment, the first and second AC voltage signals each have voltage values ​​in the range of 40V to 80V. As a result, the peak-to-peak value of the control signal is correspondingly 80V to 160V. Such voltage values ​​have proven advantageous and sufficient for controlling known switchable glass panels. The first and second AC voltage signals may be generated by an inverter, since the current (onboard) voltage of a vehicle is typically DC voltage.

[0023] Specifically, the objective of this method is to be achieved by a method for controlling a switchable glass panel connected between the output of a first analog amplifier and the output of a second analog amplifier, wherein one power transistor of each of the two analog amplifiers together forms an upper voltage circuit, and the other power transistor of each of the two analog amplifiers together forms a lower voltage circuit, and this method is - A step of applying a control voltage supplied by two analog amplifiers to a switchable glass panel, wherein the control voltage consists of a first AC voltage signal and a second AC voltage signal that is phase-shifted by 180° relative to the first AC voltage signal. - A step of discharging a switchable glass panel, wherein the output of the first analog amplifier is discharged via the output of the second analog amplifier, the step, and the method includes.

[0024] In one embodiment, the method is A step of discharging a switchable glass panel, wherein the output of the first analog amplifier is further discharged via a ground potential, the step is further included.

[0025] In other words, the discharging of the switchable glass panel is thus mainly performed via the output of the second analog amplifier and (further) via the ground potential.

[0026] In particular, by the above method step of discharging the switchable glass panel in at least one discharging stage, the discharging is advantageously performed via existing components, so that an additional discharging circuit and its control can be omitted. Since the microcontroller is usually used in any case in the control unit for the switchable glass, an AC voltage signal and a variable supply voltage for the output of the analog amplifier can also be generated via the microcontroller. Therefore, it is possible to adapt the signal form individually.

[0027] In one embodiment, the method is A step of applying a variable supply voltage to the first analog amplifier and the second analog amplifier is further included.

[0028] According to one embodiment, this variable supply voltage can also be used for discharge, in which case the discharge is performed via the power transistor of the upper voltage circuit by adapting the variable supply voltage. Adapting the variable supply voltage can be understood here as meaning that the set value of the variable supply voltage in the discharge stage is lower than the voltage value of the control voltage. For example, but not limited to, the set value of the variable supply voltage may be 1 volt less than the voltage value of the control voltage. Adaptation may be performed, for example, by time shifting two sinusoidal voltage profiles relative to each other.

[0029] In this embodiment, since only existing components are used for discharge in combination with advantageous operation, the discharge circuit can be omitted.

[0030] Furthermore, an automobile having a glass panel device is claimed and disclosed in the context of this application. Preferably, the glass panel device is the glass panel device already described above.

[0031] Exemplary embodiments of the present invention are described in more detail below with reference to the drawings. These drawings are shown below in a partially and significantly simplified form. [Brief explanation of the drawing]

[0032] [Figure 1] This is a schematic circuit diagram of the glass panel apparatus according to the present invention according to the first embodiment. [Figure 2] This is a schematic circuit diagram of the glass panel device according to the present invention according to a second embodiment. [Figure 3] This is a schematic circuit diagram of a second voltage regulator for applying a variable supply voltage to the lower voltage circuit. [Figure 4] This is a schematic circuit diagram of the glass panel apparatus according to the present invention according to a third embodiment. [Modes for carrying out the invention]

[0033] In each figure, components that have the same effect are represented by the same reference number.

[0034] Figure 1 schematically shows the circuit diagram of the glass panel device 2. The glass panel device 2 has a switchable glass panel 4, which is represented in the circuit diagram simply as an RC element in the form of an equivalent circuit.

[0035] The glass panel apparatus 2 further comprises a control unit 6 having a first analog amplifier 8 and a second analog amplifier 10. For simplicity, only the two analog amplifiers 8 and 10 of the control unit 6 are shown in the figure. However, it goes without saying that this type of representation is not limiting in nature to the control unit 6. Rather, further components not described herein may be part of the control unit 6.

[0036] The control unit 6 controls a control voltage U, which is composed of a first AC voltage signal (S1) amplified by the first analog amplifier 8 and a second AC voltage signal S2 (see Figure 2) amplified by the second analog amplifier 10. A The switchable glass panel 4 is controlled (see Figure 2). The first AC voltage signal S1 is electrically phase-shifted by 180° relative to the second AC voltage signal S2.

[0037] Furthermore, the first analog amplifier 8 has two first power transistors T1 and T2, and the second analog amplifier has two second power transistors T3 and T4. In exemplary embodiments, the power transistors T1, T2, T3, and T4 are embodied as MOSFETs. The power transistors T1 and T3 of each of the two analog amplifiers 8 and 10 together form an upper voltage circuit 12, schematically represented by a dashed rectangle in the figure. The power transistors T2 and T4 of each of the two analog amplifiers 8 and 10 similarly form a lower voltage circuit 14.

[0038] The switchable glass panel 4 is connected between the output OUT of the first analog amplifier 8 and the output COM of the second analog amplifier 10.

[0039] Similarly, as shown in Figure 1, the control unit 6 further includes a first voltage regulator 16. The first voltage regulator 16 is configured to apply a variable supply voltage to the upper voltage circuit 12 and is electrically connected to the upper voltage circuit 12. In Figure 1, the first voltage regulator 16 and its electrical connection to the upper voltage circuit 12 are represented in a greatly simplified manner.

[0040] The minimization of power loss described above is achieved by the glass panel apparatus 2 described above, for example, during the discharge phase of the switchable glass panel 4, such that a variable supply voltage is applied to the output COM by one of the second power transistors T3 of the second analog amplifier 10. However, this discharge during application to output COM is further carried out through the (body) diode of one of the first power transistors T1, which is embodied as a MOSFET, at the output OUT of the first analog amplifier 6. The output OUT of the first analog amplifier 8 is further discharged to ground potential through the other first power transistor T2.

[0041] The set value of the variable supply voltage is already lower than the voltage present at the output OUT of the first analog amplifier 8 at this point. Therefore, nothing is supplied from the first voltage regulator 16. Thus, the discharge current at the output OUT of the first analog amplifier 8 is directly conducted to the output COM of the second analog amplifier 10 via the (body) diode of one of the first power transistors T1 and via the one of the second power transistors T3. This eliminates the need for additional discharge circuits and their operation.

[0042] Therefore, the present invention utilizes existing diodes of power transistors T1 and T3 with a voltage profile of a variable supply voltage that can be easily adapted. Furthermore, the present invention takes advantage of the situation of an asynchronous voltage regulator architecture, namely, a situation where it is only possible to supply current and not discharge it.

[0043] A further prerequisite is that the output capacitance of the voltage regulator must be considerably lower than the capacitance of the film, for example, in a ratio of 1:10. The variable supply voltage is adapted during operation so that the setting of this voltage during the discharge phase is approximately 1V lower than the desired voltage profile.

[0044] As already mentioned, bipolar transistors can also be used instead of MOSFETs. However, a diode that functions according to the (body) diode of the MOSFET variant described above must be implemented in parallel with transistors T1 and T3.

[0045] Figure 2 shows a circuit diagram of an alternative embodiment of the glass panel apparatus 2 according to the present invention. This alternative embodiment substantially corresponds to the embodiment shown in Figure 1. For this reason, the circuit diagram in Figure 2 is represented in a more simplified form compared to the circuit diagram in Figure 1.

[0046] Unlike the embodiment shown in Figure 1, the glass panel device 2, particularly the control unit 4, has a discharge unit 18 connected between the output OUT of the first analog amplifier 8 and the output COM of the second analog amplifier 10. The discharge unit 18 enables the discharge of the aforementioned switchable glass panel 4 in an alternative manner.

[0047] Figure 3 shows a detailed structure of the second voltage regulator 20, which includes a switch 22, a diode 24, and a comparator 26. The second voltage regulator 20 functions to apply a variable supply voltage to the lower voltage circuit 14 (see Figure 4).

[0048] Figure 4 shows a third embodiment of the glass panel device 2. The third embodiment of the glass panel device 2 also substantially corresponds to the first embodiment shown in Figure 1. However, in this embodiment, the glass panel device 2 and in particular the control unit 6 further include the above-mentioned second voltage regulator 20 electrically connected to the lower voltage circuit 14, as shown in a greatly simplified manner. General operating modes have already been described above and will be omitted here.

[0049] The present invention is not limited to the exemplary embodiments described above. Rather, those skilled in the art can derive other variations of the present invention without departing from the subject matter of the invention. In particular, all the individual features described in relation to the exemplary embodiments can be combined with each other in other ways without departing from the subject matter of the invention. [Explanation of Symbols]

[0050] 2. Glass Panel Device 4 Switchable Glass Panels 6. Control Unit 8. First Analog Amplifier 10. Second Analog Amplifier 12 Upper voltage circuit 14 Lower voltage circuit 16. First voltage regulator 18 Discharge Unit 20 Second voltage regulator 22 switches 24 diodes 26 Comparator S1 First AC voltage signal S2 Second AC voltage signal U A Control voltage OUT Output of the first analog amplifier COM output of the second analog amplifier T1 First power transistor of the first analog amplifier T2 First power transistor of the first analog amplifier T3 Second power transistor of the second analog amplifier T4 Second power transistor of the second analog amplifier

Claims

1. Glass panel device (2) - Switchable glass panel (4) and - A control unit (6) for controlling the switchable glass panel (4) with a control voltage (UA), wherein the control voltage (UA) consists of a first AC voltage signal (S1) and a second AC voltage signal (S2), and the first AC voltage signal (S1) is phase-shifted by 180° relative to the second AC voltage signal (S2), In a glass panel device (2) equipped with, - The control unit (6) includes a first analog amplifier (8) for amplifying the first AC voltage signal (S1) having two first power transistors (T1, T2), and a second analog amplifier (10) for amplifying the second AC voltage signal (S2) having two second power transistors (T3, T4), wherein one power transistor (T1, T3) of each of the two analog amplifiers (8, 10) together forms an upper voltage circuit (12), and the other power transistor (T2, T4) of each of the two analog amplifiers (8, 10) together forms a lower voltage circuit (14). - The switchable glass panel (4) is connected between the output (OUT) of the first analog amplifier (8) and the output (COM) of the second analog amplifier (10). - The control unit (6) further includes a first voltage regulator (16) configured to apply a variable supply voltage to the upper voltage circuit (12), A glass panel device (2) characterized by the following.

2. The control unit (6) has a discharge unit (18) connected between the output (OUT) of the first analog amplifier (8) and the output (COM) of the second analog amplifier (10). The glass panel apparatus (2) according to claim 1, characterized in that...

3. The control unit (6) further includes a second voltage regulator (20) configured to apply a variable supply voltage to the lower voltage circuit (14). A glass panel apparatus (2) according to claim 1 or 2, characterized in that...

4. The second voltage regulator (20) comprises a switch (22), a diode (24), and a comparator (26). The glass panel apparatus (2) according to claim 3, characterized in that...

5. The first power transistors (T1, T2) of the first analog amplifier (8) and the second power transistors (T3, T4) of the second analog amplifier (10) are formed as bipolar transistors or MOSFETs. A glass panel apparatus (2) according to claim 1 or 2, characterized in that...

6. The first AC voltage signal (S1) and the second AC voltage signal (S2) each have voltage values ​​in the range of 40V to 80V. A glass panel apparatus (2) according to claim 1 or 2, characterized in that...

7. A method for controlling a switchable glass panel (2) connected between the output (OUT) of a first analog amplifier (8) and the output (COM) of a second analog amplifier (10), wherein one power transistor (T1, T3) of each of the two analog amplifiers (8, 10) together forms an upper voltage circuit (12), and the other power transistor (T2, T4) of each of the two analog amplifiers (8, 10) together forms a lower voltage circuit (14). - A step of applying a control voltage (UA) supplied by the two analog amplifiers (8, 10) to the switchable glass panel (4), wherein the control voltage (UA) consists of a first AC voltage signal (S1) and a second AC voltage signal (S2) that is phase-shifted by 180° with respect to the first AC voltage signal (S1), - A step of discharging the switchable glass panel (4), wherein the output (OUT) of the first analog amplifier (8) is discharged via the output (COM) of the second analog amplifier (10), Methods that include...

8. A step of discharging the switchable glass panel (4), wherein the output (OUT) of the first analog amplifier (8) is further discharged via ground potential, The method according to claim 7, further comprising:

9. The steps include applying a variable supply voltage to the first analog amplifier (8) and the second analog amplifier (10), The method according to claim 7 or 8, further comprising:

10. The step of discharging the switchable glass panel via the power transistors (T1, T3) of the upper voltage circuit (12) by adjusting the variable supply voltage so that the set value of the variable supply voltage is smaller than the voltage value of the control voltage (UA), The method according to claim 9, further comprising:

11. An automobile having the glass panel device (2) according to claim 1 or 2.

12. The first analog amplifier (8) amplifies the first AC voltage signal (S1) at the output (OUT) of the first analog amplifier (8) using the two first power transistors (T1, T2), and the output (OUT) is provided between the two first power transistors (T1, T2) connected in series. The second analog amplifier (10) amplifies the second AC voltage signal (S2) at its output (COM) using the two second power transistors (T3, T4), and the output (COM) is provided between the two second power transistors (T3, T4) connected in series. The glass panel apparatus (2) according to claim 1, characterized in that...

13. The method according to claim 7, wherein the output (OUT) of the first analog amplifier (8) is provided between two first power transistors (T1, T2) connected in series, and the output (COM) of the second analog amplifier (10) is provided between two second power transistors (T3, T4) connected in series.

Images