Control unit
The invention relates to a control unit ( 40 ) for driving an electric load, in particular an electric machine, having a first and a second voltage terminal ( 46, 48 ) in order to supply the control unit ( 40 ) with electrical energy, a capacitor ( 58 ), which is connected between the voltage terminals ( 46, 48 ), at least one half-bridge ( 15 ), which is connected between the voltage terminals ( 46, 48 ), wherein the half-bridge ( 50 ) has two controllable switches ( 52, 54 ), between which there is formed a half-bridge tap ( 50 ) for connecting the load, a safety circuit ( 66 ), which is designed to close one of the controllable switches ( 52, 54 ) of the half-bridge ( 50 ) in the event of a fault, a discharge circuit ( 68 ), which is designed to connect the voltage terminals ( 46, 48 ) electrically in the event of a fault, and having a control circuit ( 18 ) which is designed to provide a control signal ( 78 ) which triggers the safety circuit ( 66 ) and the discharge circuit ( 68 ) in the event of the detected fault.
1. A control unit for driving an electric load, the control unit comprising:
a low voltage section including a microcontroller and a first portion of a signal transmitter;
a high voltage section including a second portion of the signal transmitter, a safety circuit, a discharge circuit, a control circuit, a first voltage terminal and a second voltage terminal in order to supply the control unit with electrical energy;
a capacitor, which is connected between the first voltage terminal and the second voltage terminals;
at least one half-bridge, which is connected between the first voltage terminal and the second voltage terminals, wherein the half-bridge includes a first controllable switch and a second controllable switch, between which there is formed a half-bridge tap for connecting the load;
wherein the safety circuit is configured to receive a control signal from the control circuit and to close one of the first controllable switch and the second controllable switch of the half-bridge in the event of a fault, the safety circuit including a third controllable switch and a resistor;
wherein the discharge circuit is designed to connect the first voltage terminal and the second voltage terminals electrically in the event of the fault;
wherein the control circuit is coupled to the safety circuit and the discharge circuit and designed to provide the control signal to trigger the safety circuit and the discharge circuit in the event of the fault; and
wherein the control circuit is designed to trigger the safety circuit and the discharge circuit substantially at the same time.
2. The control unit according to claim 1 , wherein the discharge circuit comprises a resistor and a fourth controllable switch, wherein the resistor and the controllable switch are connected in series between the voltage terminals.
3. The control unit according to claim 1 , wherein the third controllable switch is designed to connect the first voltage terminal to a control input of the second controllable switch.
4. The control unit according to claim 1 , wherein the control unit comprises the high-voltage section and the low-voltage section, wherein the high voltage section has a supply voltage which is greater than a supply voltage of the low-voltage section and wherein the high-voltage section is galvanically isolated from the low-voltage section.
5. The control unit according to claim 4 , wherein the control circuit is associated with the high-voltage section.
6. The control unit according to claim 5 , wherein the control circuit is connected via signal transmission means to detection means of the low-voltage section, wherein the detection means are designed to monitor at least one function of the low-voltage section.
7. The control unit according to claim 1 , wherein the control circuit is connected to a detector designed to monitor at least one function of the control unit.
8. The control unit according to claim 1 , wherein the first voltage terminal is associated with a high voltage potential and the second voltage terminal is associated with a low voltage potential, wherein the second controllable switch which can be actuated by the safety circuit is connected to the second voltage terminal.
9. A drive train of a motor vehicle comprising an electric machine for providing driving power, an energy supply unit for providing electrical energy and the control unit according to claim 1 for driving the electric machine.
10. The control unit according to claim 1 , wherein the control circuit comprises an optocoupler configured to galvanically isolate the high-voltage section from the low-voltage section, wherein the high voltage section has a supply voltage which is greater than a supply voltage of the low-voltage section.
11. A method for initiating a safety mode of a control unit for driving an electric load, wherein the control unit includes a high voltage section, a low voltage section and has a first and a second voltage terminal in order to supply said control unit with electrical energy, a capacitor, which is connected between the voltage terminals, at least one half-bridge, which is connected between said voltage terminals, wherein the half-bridge includes a first controllable switch and a second controllable switch, between which there is formed a half-bridge tap for connecting the load, said method comprising the steps:
detecting a fault,
closing one of the first controllable switch and the second controllable switch of the half-bridge by means of a safety circuit,
triggering both the safety circuit and a discharge circuit with a control signal from a control circuit,
connecting the voltage terminals electrically by means of the discharge circuit, and
wherein the control circuit is designed to trigger the safety circuit and the discharge circuit substantially at the same time.