Power electronics for operating electric machine, electric drive unit, method for operating power electronics

Abstract

The invention relates to a power electronics device (1) for operating an electric machine, comprising at least one half-bridge (3) which is or can be assigned to a phase (2) of a drive winding of the electric machine, the half-bridge (3) having at least one first controllable semiconductor switch (4), and the first controllable semiconductor switch (4) having at least one second controllable semiconductor switch (5). At least one gate driver (6) is connected upstream of the first semiconductor switch (4) in order to actuate the first semiconductor switch. According to the invention, at least two gate drivers (6), which are electrically connected in parallel, are connected upstream of the first semiconductor switch (4), and the gate drivers (6) are each designed to apply a predetermined current to the first semiconductor switch (4) in order to actuate the first semiconductor switch (4).

Description

Technical Field

[0001] The present invention relates to a power electronic device for operating a motor, the power electronic device having at least one half-bridge, the half-bridge being associated with or configurable with a phase of a drive winding of the motor, wherein the half-bridge has at least one operable first semiconductor switch, and wherein at least one gate driver is connected upstream of the first semiconductor switch to operate the first semiconductor switch.

[0002] Furthermore, the present invention relates to an electric drive unit having such power electronic equipment and a method for operating such power electronic equipment. Background Technology

[0003] The type of power electronic equipment mentioned at the beginning is known in the prior art. The core research and development theme for this type of power electronic equipment is its usability and robustness against functional failures, especially in automotive applications, such as highly automated or autonomous driving. In particular, it is essential to reliably prevent the failure of vehicle components such as brakes and steering systems. If the brakes and / or steering system are designed as drive-by-wire systems, adjustment signals are implemented solely through electronic signals, without any mechanical intervention (durchgriff) as a backup level. Therefore, it is known to implement corresponding electrical component redundancy, such as multiple motors and / or power electronic equipment.

[0004] For example, publication DE 10 2014 203 568 A1 discloses an electric drive system having a motor with at least two three-phase winding branches, wherein each of these winding branches is equipped with its own inverter, and each of the inverters is equipped with its own DC voltage source. This modular approach should achieve a redundant system in which an emergency operation function with limited effective power can be established in the event of a failure of a single DC voltage source by deactivating the defective or faulty component and supplying the motor with reduced power through the remaining inverter components.

[0005] Publication DE 10 2014 113 542 A1 discloses an electric drive system comprising: at least one multiphase motor having at least two redundant phase winding branches for at least one phase; and a circuit device having independent circuit units for powering the phase winding branches, wherein at least one circuit unit is configured to power at least two phase winding branches, the phases to which these phase winding branches belong are different from each other. Specifically, at least one circuit unit has an independent power supply section, such that in the event of a fault, at least the remaining operable modules can be used to continue operating the motor. Summary of the Invention

[0006] The power electronic device according to the invention, possessing the features of claim 1, is distinguished by at least two parallel-connected gate drivers upstream of a first semiconductor switch, each gate driver being designed to apply a predetermined current to the first semiconductor switch for operation. A key difference from the power electronic device mentioned earlier is that the gate drivers are not designed to apply voltage to the respective semiconductor switches as is typically the case, but rather to apply current. The invention is based on the understanding that the area with the highest risk of failure is not the motor, but the current supply section of the power electronic device. Therefore, the power electronic device described earlier involves a significantly more complex circuit than the power electronic device proposed according to the invention, wherein the circuit is particularly conditioned on at least one six-phase motor, or wherein at least one half-bridge of the half-bridge with semiconductor switches must be redundantly implemented, thus arranging the structure to operate as desired. Because the power electronic device according to the invention is current-controlled in this respect, it is advantageously possible to eliminate switching or isolation devices between the gate drivers, resulting in a reduced number of components and thus lower cost. In a parallel circuit of two redundantly implemented voltage-controlled gate drivers, such devices are mandatory, as they would otherwise block each other. In the power electronic device according to the invention, the corresponding high overhead for switching and / or isolation is advantageously eliminated. Redundancy is achieved simply by replicating the gate driver as a front-end component, without requiring additional components.

[0007] According to a preferred embodiment of the invention, the gate drivers are configured to have or be connected to a high-impedance current source. Therefore, the power electronic device according to the invention offers significant advantages. Specifically, it does not use a low-impedance voltage source, unlike the known power electronic devices mentioned earlier.

[0008] Particularly preferred is that the power electronic device includes a control unit configured to individually operate the gate driver to selectively or concurrently apply current to the first semiconductor switch during normal operation. The advantage of this is that the current supply to the semiconductor switch is always guaranteed.

[0009] According to a preferred improvement of the invention, the power electronic device has a control device configured to deactivate the relevant gate driver in the event of a functional failure. This advantageously ensures that even if one of the current supply components provided by the gate driver fails, the semiconductor switch can reliably receive current through the still-operating gate driver, and operation is not affected by the failed or defective gate driver.

[0010] A particularly preferred configuration is that the half-bridge has at least one operable second semiconductor switch, with at least two additional gate drivers connected in parallel upstream of the second semiconductor switch. Each gate driver is designed to apply a predetermined current to the second semiconductor switch to operate it. The advantage of this is that each semiconductor switch has advantageous redundancy in its current supply.

[0011] According to a preferred embodiment of the invention, the first semiconductor switch is designed as a high-side switch, and the second semiconductor switch is designed as a low-side switch. In this type of design, the advantages of the power electronic device according to the invention are extremely significant.

[0012] The electric drive unit having the features of claim 7 has a motor and is distinguished by the power electronics according to the invention. This results in the advantages already mentioned.

[0013] A particularly preferred configuration is that the motor has three electrical phases, and the power electronics have such a half-bridge for each of the electrical phases. This provides a particularly advantageous redundancy in terms of current supply for each of the electrical phases.

[0014] The method for operating the power electronic device according to the invention, having the features of claim 9, is distinguished by manipulating the gate driver during normal operation to selectively or in parallel apply a predetermined current to the semiconductor switch. This enables particularly advantageous application feasibility for the power electronic device, wherein a reliable current supply to the semiconductor switch is always ensured.

[0015] According to a preferred improvement of the invention, the gate drivers are monitored for functional failures, and if a functional failure of one of the gate drivers is identified, the corresponding gate driver is deactivated. This advantageously ensures that even if one of the current supply components provided by the gate drivers fails, the semiconductor switch can reliably receive current through the still-operating gate drivers, and operation is not affected by the failed or defective gate drivers. Attached Figure Description

[0016] Further preferred features and combinations thereof are derived from the foregoing description and the claims. The invention will now be explained in detail with reference to the accompanying drawings. Therefore: Figure 1 A partial circuit diagram of an advantageous power electronic device is shown, and Figure 2 A method for operating power electronic devices is shown. Detailed Implementation

[0017] Figure 1 A partial circuit diagram of a power electronics device 1 is shown, which is used to operate phase 2 of the drive winding of a motor, which is not shown in detail elsewhere. The power electronics device 1 has a half-bridge 3 associated with phase 2. Preferably, the power electronics device 1 has such a half-bridge 3 for each of the phases.

[0018] Half-bridge 3 has a controllable first semiconductor switch 4, which is designed herein as a high-side switch HS. Additionally, half-bridge 3 has a controllable second semiconductor switch 5, which is designed herein as a low-side switch LS.

[0019] Two first gate drivers 6 connected in parallel are connected upstream of the first semiconductor switch 4 to control it. The first gate drivers 6 are respectively designed to apply a predetermined or pre-defined current to the first semiconductor switch 4 to control it.

[0020] Two second gate drivers 7 connected in parallel are connected upstream of the second semiconductor switch 5 to control it. The second gate drivers 7 are respectively designed to apply a predetermined or pre-defined current to the second semiconductor switch 5 to control it.

[0021] Gate drivers 6 and 7 each have a high-impedance current source or are connected to a high-impedance current source. Gate drivers 6 and 7 are equipped with a control device 8, which is configured to operate gate drivers 6 and 7 respectively to selectively or in parallel apply current to the corresponding semiconductor switches 4 and 5 during normal operation and to deactivate the relevant gate drivers in the event of a functional failure. Finally, the half-bridge 3 is also equipped with a supply unit 9.

[0022] The following is for reference. Figure 2 To describe an advantageous method for operating power electronic device 1. Therefore, Figure 2 The method is illustrated in the flowchart. Specifically, this method ensures that semiconductor switches 4 and 5 are always reliably supplied with current in order to operate the motor.

[0023] In step S1, the method begins by operating the gate drivers 6 and 7 via the control device 8 during normal operation to apply a predetermined current to the respective semiconductor switches 4 and 5 in parallel, and especially alternately. Alternatively, the control device 8 may operate only one of the gate drivers 6 and 7 respectively to apply a predetermined current to the respective semiconductor switches 4 and 5 selectively.

[0024] In parallel, gate drivers 6 and 7 are monitored for functional faults. If a functional fault is identified in one of the gate drivers 6 and 7, the method continues in step S2. In step S2, the corresponding gate driver 6 or 7 is deactivated by the control device 8 to ensure that its fault does not affect the operation of the power electronic device 1. Operation of the gate drivers 6 and 7 that are still operational continues normally.

[0025] Once a defective or faulty gate driver 6 or 7 is identified as operational again, it is reactivated via control device 8. The method then concludes with step S3.

Claims

1. Power electronics (1) for operating an electric machine, - having at least one half-bridge (3) which is assigned or can be assigned to a phase (2) of drive windings of the electric machine, - wherein, the half-bridge (3) having at least one controllable first semiconductor switch (4), and - wherein at least one gate driver (6) is connected upstream of the first semiconductor switch (4) for controlling the first semiconductor switch, characterized in that - at least two parallel electrically connected gate drivers (6) are connected upstream of the first semiconductor switch (4), and - the gate drivers (6) are each designed for loading the first semiconductor switch (4) with a predefinable current for controlling the first semiconductor switch.

2. The power electronic device of claim 1, wherein, The gate drivers (6) each have or are connected with a high-impedance current source.

3. The power electronic device according to any of the preceding claims, characterized in that A control device (8) is provided for controlling the gate drivers (6) for selectively or in parallel loading the first semiconductor switch (4) with current in normal operation.

4. The power electronic device according to any of the preceding claims, characterized in that A control device (8) is provided for deactivating the relevant gate driver (6) in the event of a functional fault.

5. The power electronic device according to any of the preceding claims, characterized in that, The half-bridge (3) has at least one controllable second semiconductor switch (5), at least two further parallel electrically connected gate drivers (7) being connected upstream of the second semiconductor switch, wherein the gate drivers (7) are each designed for loading the second semiconductor switch (5) with a predefinable current for controlling the second semiconductor switch.

6. The power electronic device of claim 5, wherein, The first semiconductor switch (4) is designed as a high-side switch and the second semiconductor switch (5) is designed as a low-side switch.

7. An electric drive unit having an electric machine, characterized by The power electronics (1) according to any one of the preceding claims.

8. The drive unit of claim 7, wherein, The electric machine has three electric phases (2) and the power electronics (1) has such a half-bridge (3) for each of the electric phases (2).

9. A method for operating a power electronic device (1) according to any one of claims 1 to 6, characterized in that The gate drivers (6, 7) are controlled in normal operation for selectively or in parallel loading the semiconductor switches (4, 5) with a predefinable current.

10. The method of claim 9, wherein, The gate drivers (6, 7) are monitored for a functional fault and the respective gate driver (6, 7) is deactivated if a functional fault of one of the gate drivers (6, 7) is identified. The gate drivers (6, 7) are monitored for a functional fault and the respective gate driver (6, 7) is deactivated if a functional fault of one of the gate drivers (6, 7) is identified.

Images