Driver device, power electronics, controller and operating method

Abstract

The invention relates to a driver device (1) for a power semiconductor switch (2), having at least one control apparatus for providing a driver voltage for switching the power semiconductor switch (2), having an output (4) for outputting a control voltage to a gate (G) of the power semiconductor switch (2), and having at least one adjustable electrical resistance device (7, 8), which couples the control apparatus to the output (4) in order to adjust a current impressed into the gate (G) by the driver voltage (G), wherein the resistance device (7, 8) has a plurality of electric resistors (RG1-RG6) and a plurality of controllable switching transistors (T1-T8). According to the invention, the resistance device (7, 8) has at least three resistors (RG1-RG6), of which a first and a second resistor (RG1, RG3; RG4, RG6) are connected in parallel to one another, and a third resistor (RG2; RG5) is connected on the input side to the first and to the second resistor (RG1, RG3; RG4, RG6) and on the output side to the output (4), and a switching transistor T1, T2; T3, T4) is connected upstream of each of the first and the second resistor (RG1, RG3; RG4, RG6).

Description

[0001] Description

[0002] title

[0003] The present invention relates to a driver device for a power semiconductor switch, comprising at least one control device for providing a driver voltage for switching the power semiconductor switch, an output for outputting a control voltage to a gate of the power semiconductor switch, and at least one adjustable electrical resistance device that couples the control device to the output in order to adjust a current impressed into the gate by the driver voltage, wherein the resistance device comprises at least one electrical resistor and at least one controllable switching transistor.

[0004] Furthermore, the present invention relates to power electronics, in particular power converters, for a motor vehicle, comprising at least one power semiconductor switch and at least one driver device as described above.

[0005] Furthermore, the invention relates to a control unit with such power electronics, as well as a method for operating the driver device, in particular the driver device of the power electronics or the control unit.

[0006] State of the art

[0007] Driver devices of the type mentioned above are already known from the prior art. For example, German patent application DE 10 2006 034351 A1 discloses a driver device of this type. In industrial environments, the specific implementation and realization of a driver device, often also referred to as a gate driver, plays a significant role due to the large number of individual components and the required installation space. Passive-resistive circuits have become established for controlling power semiconductor switches; these circuits operate robustly and reliably and require only a small number of components. To increase the robustness of a control circuit, it is known to use electrical resistors that selectively limit the current supplied or impressed at the output.The aforementioned patent application also proposes connecting a controllable switching transistor upstream of each resistor, with the resistors being connected to the common output so that, depending on the transistor's control signal, one or more of the resistors are used. This allows for an adjustable resulting gate current that reliably and precisely switches the power semiconductor switch on and off.

[0008] Disclosure of the invention

[0009] The driver device according to the invention, with the features of claim 1, has the advantage over the prior art that at least one component is eliminated, even though three resistors are used for the resistor device. It eliminates the need for a switching transistor compared to the number of resistors used, thus advantageously reducing installation space and manufacturing costs. Furthermore, the driver device, due to the design according to the invention, does not require an additional connection pin, further reducing costs and installation space. According to the invention, the at least one resistor device comprises three resistors, of which a first and a second resistor are connected in parallel, a third resistor is connected to the first and second resistors on the input side and to the output on the output side, and a switching transistor is connected upstream of both the first and second resistors.Thus, the resistor device comprises a first series circuit consisting of a first transistor and a first resistor, a second series circuit consisting of a second transistor and a second resistor, and a third resistor, wherein the third resistor is connected on the input side to the first and second resistors and on the output side to the output. The driver device according to the invention therefore has only two switching transistors for three usable resistors of the resistor device.Because the three resistors are connected in a T-shape, with the third resistor connected to the outputs of the first and second resistors and to the gate on its output side, the control of the two switching transistors results in either the first and third resistors being used, the second and third resistors being used, or the first and second resistors being used together with the third resistor. Particularly when the electrical resistances have different values, this configuration of the resistor array ensures variable or flexible control of the power semiconductor switch.

[0010] Furthermore, it is preferably provided that the driver device comprises several identical resistor devices connected in parallel and linked to the common output. By providing multiple resistor devices, the performance and variability of the driver device are advantageously scalable and adaptable.

[0011] According to a preferred embodiment of the invention, a first resistor is configured for switching on the power semiconductor switch, and a second resistor is configured for switching off the power semiconductor switch. This allows for optimal operation of both the switching on and switching off processes. Advantageously, a switching transistor for the switching on process and a switching transistor for the switching off process are connected in series in the form of a half-bridge of the driver circuit.

[0012] Optionally, the resistor assembly has a first half-bridge connected upstream of the first resistor and a second half-bridge connected upstream of the second resistor. This allows the resistor assembly to be used for both the switch-on and switch-off processes. According to a further embodiment of the invention, the driver assembly preferably has several resistor assemblies, wherein the second resistor of one resistor assembly forms the third resistor of another resistor assembly. Thus, the two resistor assemblies share a single resistor.This results in a nested design of the driver device, in which the resistor devices form a kind of double-T structure, making it advantageous to adjust further effective resistances and saving one resistor and one switching transistor compared to the two parallel-connected resistor devices as described above.

[0013] Preferably, the resistors are spaced apart from the control device, in particular arranged outside the control device. Due to the expected heat losses, this has the advantage that the control device is not affected by the losses occurring at the resistors.

[0014] Furthermore, the resistors are preferably designed using discrete components to be particularly robust and durable.

[0015] The power electronics according to the invention, with the features of claim 8, are characterized by the inventive design of the driver device. This results in the advantages already mentioned above.

[0016] The control unit according to the invention, with the features of claim 9, is characterized by the power electronics according to the invention. The advantages already mentioned above result for the control unit.

[0017] The inventive method for operating the inventive driver device is characterized by the features of claim 10 in that the switching transistors are controlled depending on a requested target gate current and / or a requested target gate voltage. In particular, either the first switching transistor or the second switching transistor or both switching transistors are switched on or made conductive simultaneously to ensure the desired target gate current, which leads to the switching on and off of the power semiconductor switch. The switching transistors are particularly preferably controlled with a predefinable or predetermined switching pattern to generate a desired gate current, which results from the set resistances.The total resistance then corresponds to the set combination of the three T-shaped resistors or the at least one advantageous resistor arrangement. Optionally, at least one such resistor arrangement is provided for both switching on and switching off.

[0018] Further advantages and preferred features and combinations of features will become apparent in particular from the foregoing and from the claims. The invention will now be explained in more detail with reference to the drawings. To this end, we show...

[0019] Figure 1 shows a power electronics unit,

[0020] Figure 2 shows an advantageous driver device for the power electronics,

[0021] Figure 3 shows another embodiment of the driver device and

[0022] Figure 4 shows another embodiment of the driver device, each in a simplified representation.

[0023] Figure 1 shows a simplified representation of a driver device 1, in particular a gate driver, for a power semiconductor switch 2 of a power electronics circuit 3, which is only indicated here. The power semiconductor switch 2 is, for example, designed as an IGBT or MOSFET switch. The main current path of the power semiconductor switch 2 runs from a collector C to an emitter E, or, in the case of the MOSFET, from the drain to the source terminal. This main current path is controlled by a voltage and / or a current applied to the gate G of the power semiconductor switch 2. The main current path is controlled by the voltage or the state of charge of the gate capacitance, which is charged or discharged by the gate current.

[0024] The driver device 1 provides a driver voltage at its output 4, which is applied to the gate G of the power semiconductor switch via a cable or lead. Preferably, the lead has no ohmic resistance and only very low inductance. The driver device further comprises two controllable semiconductor switches, in particular switching transistors T1 and T2, which can be controlled by a control unit 5 of the driver device 1. The control unit 5 comprises, for example, a microprocessor that controls the transistors T1 and T2 depending on whether the power semiconductor switch 2 is to be switched on or off.

[0025] The switching transistors T1 and T2 are each coupled on their output side to an electrical resistor RG1 and RG2, respectively, and connected on their input side to a voltage source 6. Resistors RG1 and RG2 are connected to each other and to output 4 on their output side. By driving the switching transistors T1 and T2, the gate current flowing during the switching transients can be adjusted using the supply voltage U of the voltage source 6 and the electrical resistors RG1 and RG2, which are preferably different.

[0026] Resistors RG1 and RG2, together with switching transistors T1 and T2, each form a resistor assembly 7, 8, which can be controlled to supply a desired current to gate G. The possibilities for adjusting the current result from the resistors RG1 and RG2 used, the control of transistors T1 and T2, and the supply voltage. Resistor assembly 7 is used to switch on, and resistor assembly 8 is used to switch off, the power semiconductor switch 2.

[0027] To increase the application possibilities of the resistor device 7 without significantly increasing the number of components, it is preferably provided that the resistor device 7 has at least a third electrical resistor and an additional switching transistor. Figure 2 shows a simplified representation of a preferred embodiment of the driver device 1. Apart from the fact that the driver device 1 according to Figure 2 has two resistor devices 7, 8, both of which are coupled to the output 4 on the output side, the two resistor devices 7, 8 each have a third resistor RG3.

[0028] Resistors RG1 and RG3 are connected downstream of their respective switching transistors T1 and T2, and are connected to each other on the output side. A second resistor, RG2, is connected between output 4 and the junction of the first two resistors, RG1 and RG3. Resistors RG1 and RG3 are thus connected in parallel and each is connected to one of the switching transistors, T1 and T2. Resistor RG2 is connected to both resistor RG1 and resistor RG3 on its input side and to output 4 on its output side. This results in a T-shaped connection of resistors RG1, RG2, and RG3. Depending on which of the switching transistors, T1 or T2, is activated, either resistors RG1 and RG2 operate in series, or resistors RG3 and RG2 operate in series, or resistors RG1 and RG3 operate in parallel and in series with resistor RG2.

[0029] The same applies to the second resistor assembly 8, which comprises the electrical resistors RG4, RG5, and RG6 as well as the transistors T3 and T4. The transistors T3 and T4 and the resistors RG4, RG5, and RG6 are interconnected in the same way as those of the resistor assembly 7.

[0030] Resistor 7 is configured to switch on the power transistor 2, and resistor 8 is configured to switch it off. Resistors 7 and 8 can also be extended or combined to enable special switching configurations.

[0031] In a first embodiment, a control unit 5 is configured to control all transistors T1, T2, T3, and T4. Alternatively, transistors T3 and T4 are assigned to an additional control unit 5', as indicated by dashed lines in Figure 2. The three electrical resistors of each resistor assembly 7, 8 are preferably configured differently from one another. In particular, at least one of the electrical resistors of one of the resistor assemblies 7, 8 is configured differently from the other electrical resistors of the same resistor assembly 7, 8. Due to the advantageous T-shaped connection of the resistors RG1, RG2, and RG3 or RG4, RG4, and RG6, not only two, but three almost individually adjustable effective resistances per resistor assembly 7, 8 can actuate the gate G. This will be explained in more detail below with regard to the resistor assembly 7:

[0032] If only switching transistor T1 is activated, a current flows from switching transistor T1 through resistor RG1 and the connected resistor RG2, as indicated by arrow 9, resulting in a first effective resistance. If only switching transistor T2 is activated, a current flows from switching transistor T2, as indicated by arrow 10, through resistor RG3 and the resistor RG2 connected in series with it, to gate G or output 4. This results in a second effective resistance. In particular, at least resistors RG1 and RG3 are different, so the second effective resistance differs from the first.

[0033] If both switching transistors T1 and T2 are activated, the current flows through both resistor RG1 and resistor RG3, and then through resistor RG2, resulting in a third effective resistance.

[0034] In the present embodiment, the resistor 7 is configured for the switch-on process and the resistor 8 for the switch-off process of the semiconductor switch 2, as already mentioned above. Thus, three nearly independent resistance values ​​can be set for both the switch-on and switch-off processes by controlling transistors T1, T2, T3, and T4. The T-shaped arrangement of resistors RG1 to RG3 and RG4 to RG6 of the respective resistor assemblies 7 and 8 makes it possible, for example, to achieve these resistance values ​​and thus the resulting gate currents without an additional output stage within a feedforward circuit. In particular, with only three resistors, a third switching transistor can be omitted, and is preferably omitted.

[0035] The three effective electrical resistances that can be achieved with the respective resistance device 7,8 can be calculated using the example of the on-resistance as follows:

[0036] Independent resistance values ​​are determined accordingly for the switch-off process. Using these three individual resistance values, the control can be optimized, particularly in the partial load range of the power semiconductor switch 2. The increased degree of freedom provided by three resistance values, with the ability to control only two switching transistors T1, T2 and T3, T4 or semiconductor switches, significantly enhances the control flexibility. This allows the gate current to be adjusted much more precisely, or adapted to a target curve, than with conventional passive-resistive drivers.

[0037] Figure 3 shows a further embodiment of the driver device 1, which differs from the previous embodiments in that half-bridges are formed by means of additional switching transistors T5, T6, T7, and T8, and that the number of degrees of freedom is thus increased even further, in particular because the resistor devices 7 and 8 can then both be used for the turn-off and turn-on processes. Furthermore, the resistors RG1 to RG6 can be connected as a voltage divider, which allows for a steady-state shift of the gate voltage or control voltage. This can be used, for example, during a short circuit or even temporarily during normal switching operation to reduce the loads on the power semiconductor switch 2.

[0038] By using n half-bridges (n = integer) within the

[0039] driver or driver device 1 with m T-shaped

[0040] By using resistor devices 7 and / or 8 (m = whole number), the number of switchable resistors RG and thus the control flexibility of the power semiconductor switch 2 can be further increased.

[0041] Figure 4 shows a further embodiment of the driver device 1, which differs from the previous embodiments in that one of the four available connection pins of the driver stage is for an “active miller clamping” R mcThe remaining three connection pins are used to adjust the resulting gate resistance. In this embodiment, the resistor assemblies 7 and 8 are interconnected in a double-T configuration. The driver assembly 1 has three half-bridges, each with two switching transistors T1 to T6, with a seventh switching transistor T7 assigned to the fourth connection pin. Resistor RG1 is connected to the half-bridge between switching transistors T5 and T6, and resistor RG2 is connected in series with it. Resistor RG2 is connected to output 4 or gate G on its output side. Resistor RG4 is connected to the half-bridge between switching transistors T3 and T4, and resistor RG3 is connected in series with it.On the output side, resistor RG3 is connected between resistors RG1 and RG2, so that resistors RG4 and RG3 are connected in parallel to resistor RG1. Resistor RG5 is also connected in parallel to resistor RG4 and is connected to the half-bridge between switching transistors T1 and T2. On the output side, resistors RG5 and RG4 are connected to resistor RG3.

[0042] Despite the fact that only three connection pins are available, a high number of effective individual gate resistors are still achieved by controlling the switching transistors T1 to T6 or the resistor devices.

Claims

Claims 1. Driver device (1) for a power semiconductor switch (2) , comprising at least one control device for providing a driver voltage for switching the power semiconductor switch (2), comprising an output (4) for outputting a control voltage to a gate (G) of the power semiconductor switch (2), and comprising at least one adjustable electrical resistance device (7.8), which couples the control device to the output (4) to adjust a current impressed into the gate (G) by the driver voltage, wherein the resistance device (7,8) comprises at least one electrical resistor (RGI - RGG) and at least one controllable switching transistor (T1 - T8), characterized in that the at least one resistance device (7,8) comprises at least three resistors (RGI - RGB), of which a first and a second resistor (RGI , RGS; RG4, RG6) are connected in parallel to each other, and a third resistor (RG2; RGS) is connected on the input side to the first and to the second resistor (RGI , RGS; RG4, RGG) and on the output side to the output (4), and that a switching transistor (T1 ,T2; T3,T4) is connected upstream of each of the first and the second resistor (RGI , RGS; RG4, RG6).

2. Driver device according to claim 1, characterized in that the driver device (1) comprises several identically designed resistance devices. (7.8) has which are connected in parallel to each other and are jointly connected to the output (4).

3. Driver device according to one of the preceding claims, characterized in that a first of the resistance devices (7) is designed for a switching-on process and a second of the resistance devices (8) is designed for a switching-off process of the power semiconductor switch (2).

4. Driver device according to one of the preceding claims, characterized in that the resistor device (7, 8) has a first half-bridge connected upstream of the respective first resistor (RGI ; RG4) and the Each second resistor (RGS; RGG) has a second half-bridge connected in front of it.

5. Driver device according to one of the preceding claims, characterized in that the driver device (1) has several resistor devices (7, 8), wherein the second resistor (RG3) of a resistor device (7) forms the third resistor (RG3) of a further resistor device (8).

6. Driver device according to one of the preceding claims, characterized in that the resistors (RGI -RGG) are arranged at a distance from, in particular outside of, the control device.

7. Driver device according to one of the preceding claims, characterized in that the resistors (RGI -RGG) are formed by discrete components.

8. Power electronics (3) for a motor vehicle, comprising at least one power semiconductor switch (2) and at least one driver device (1) according to one of claims 1 to 7, which is connected to a gate (G) of the power semiconductor switch (2).

9. Control unit with power electronics (3) according to claim 8.

10. Method for operating a driver device (1) according to one of claims 1 to 7, in particular a power electronics (3) according to claim 8, or a control device according to claim 9, characterized in that the switching transistors (T1 - T7) are controlled depending on a requested target gate current and / or a requested target gate voltage.

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