CN-121986443-A - Method for operating a drive system and drive system for carrying out the method

CN121986443ACN 121986443 ACN121986443 ACN 121986443ACN-121986443-A

Abstract

The invention relates to a method for operating a drive system and to a drive system for carrying out the method, wherein the drive system has a controllable rectifier which can be supplied from an ac power supply system, to the dc voltage-side connection of which an energy store and an inverter are connected, and wherein a current is determined as a control variable by a control unit, in particular a PI control unit, in such a way that a detected voltage present at the dc voltage-side connection, i.e. an intermediate circuit voltage, is set to a target voltage u_soll, and a current limited to within an upper Limit value is provided at the dc voltage-side connection of the controllable rectifier, wherein the upper Limit value is determined as a quotient of a Limit value (Limit) and a detected voltage present at the dc voltage-side connection, wherein the Limit value (Limit) is determined as a function of a temperature detected at the energy store or within the energy store and as a function of a power p_last of the inverter input at the dc voltage-side connection of the inverter.

Inventors

S. Spanger

Assignees

索尤若驱动有限及两合公司

Dates

Publication Date: 20260505
Application Date: 20240905
Priority Date: 20231011

Claims (15)

1. A method for operating a drive system, Wherein the drive system has a controllable rectifier which can be supplied from an AC network, in particular a rectifier which is connected downstream to a DC/DC converter, to the DC voltage-side connection of which an energy store, in particular a capacitor module, and to the DC voltage-side connection of the inverter are connected, It is characterized in that the method comprises the steps of, The controller, in particular the PI controller, determines the current as a regulating variable such that the detected voltage present at the dc voltage-side connection, in particular the voltage detected by the voltage sensor, i.e. the intermediate circuit voltage, is set to the target voltage u_soll, Wherein a current limited to a value below an upper limit value, in particular by a limiting element connected downstream of the controller, is provided at the DC voltage-side connection of the controllable rectifier, which current is supplied in particular to the energy store and to the DC voltage-side connection of the inverter connected in parallel to the energy store, Wherein the upper Limit value is determined as the quotient of a Limit value (Limit) and the detected voltage present at the DC voltage-side connection, Wherein the Limit value (Limit) is determined as a function of the temperature detected at or in the energy store and of the power P_Last supplied to the inverter at the DC voltage-side connection of the inverter, In particular, the Limit value (Limit) is the maximum value of the electrical power transmitted by the controllable rectifier from the ac power network to the dc voltage-side connection of the controllable rectifier.
2. The method of claim 1, wherein the step of determining the position of the substrate comprises, Detecting a temperature T in or on the accumulator, and When the second temperature threshold T2 is exceeded, a cooling mode for reducing the power loss is activated, and when the first temperature threshold T1 is undershot, in particular the cooling mode is deactivated, Particularly wherein the second temperature threshold is greater than the first temperature threshold.
3. The method according to any of the preceding claims, characterized in that, In the motor mode of the electric machine, if the power p_last input to the inverter at the dc voltage side connection of the inverter is greater than a preset power Limit value p_lim, the Limit value (Limit) is set equal to the load power, provided that: in the event of an activated cooling mode, the detected accumulator temperature T exceeds a first temperature threshold T1, Or in case the cooling mode is deactivated, the detected accumulator temperature T exceeds the second temperature threshold T2.
4. The method according to any of the preceding claims, characterized in that, The Limit value (Limit) is additionally determined from a preset power Limit value p_lim, which serves as a Limit value, in particular an upper Limit value, for the electrical power supplied by the controllable rectifier from the ac power network at the dc voltage-side connection of the controllable rectifier.
5. The method according to any of the preceding claims, characterized in that, The current supplied at the dc voltage-side connection of the controllable rectifier is also limited, in particular by the limiting element, above a lower limit value.
6. The method of claim 5, wherein the step of determining the position of the probe is performed, In case the controllable rectifier is implemented as a controllable rectifier without feedback capability, the lower limit value is zero, And/or In case the controllable rectifier is implemented as a feedback-capable controllable rectifier, the lower limit value has a non-zero negative value.
7. The method according to any of the preceding claims, characterized in that, Setting the Limit value (Limit) equal to the power Limit value P_lim, provided that In the event of a deactivated cooling mode, the detected accumulator temperature T is less than a second temperature threshold T2, And/or in the case of an activated cooling mode, the detected accumulator temperature T is below a first temperature threshold T1, Or the electric machine is operated in motor mode and the load power p_last is smaller than the power limit p_lim, and the detected temperature T is greater than the first temperature threshold T1 in the case of an activated cooling mode, Or the electric machine is operated in motor mode, and the load power p_last is smaller than the power limit p_lim, and the detected temperature T is greater than the second temperature threshold T2 if the cooling mode is deactivated.
8. The method according to any of the preceding claims, characterized in that, In the generator mode of the electric machine, a Limit value (Limit) is set to zero, provided that In the case of an activated cooling mode, the detected accumulator temperature T exceeds a first temperature threshold T1, And/or in the event that the cooling mode is deactivated, the detected accumulator temperature T exceeds a second temperature threshold T2.
9. The method according to any of the preceding claims, characterized in that, If the detected accumulator temperature T is below the first temperature threshold T1, with the cooling mode activated, the cooling mode is switched off, And/or If the detected accumulator temperature T is below the second temperature threshold T2 with the cooling mode deactivated, the cooling mode is kept off.
10. The method according to any of the preceding claims, characterized in that, If the detected accumulator temperature T exceeds the first temperature threshold T1, with the cooling mode activated, the cooling mode is kept on, And/or If the detected accumulator temperature T exceeds the second temperature threshold T2 with the cooling mode deactivated, the cooling mode is switched on.
11. A method according to any one of the preceding claims, characterized in that the power input into the intermediate circuit by the ac power network is kept always smaller than the maximum permissible power p_max, in the event of which damage occurs in the drive system.
12. Method according to any of the preceding claims, characterized in that the power limit p_lim is smaller than the maximum electric power that can be absorbed by the electric machine and is larger than the time-averaged, in particular the drive-system-consumed power or the drive-system-averaged energy consumption averaged over the entire continuous operating time of the drive system, in particular at most 20%.
13. A drive system for performing the method according to any of the preceding claims, Wherein the drive system has a controllable rectifier which can be supplied from an AC network, in particular a rectifier which is connected downstream to a DC/DC converter, to the DC voltage-side connection of which an energy store, in particular a capacitor module and a DC voltage-side connection of an inverter, are connected, It is characterized in that the method comprises the steps of, A limiting element is connected downstream of the voltage controller for controlling the voltage present at the dc voltage-side connection of the controllable rectifier, i.e. the intermediate circuit voltage, The limiting element is suitably designed to limit the output signal of the limiting element to the output signal of the quotient generator, Wherein the detected intermediate circuit voltage and Limit value (Limit) are supplied to a quotient generator.
14. A drive system according to any of the preceding claims, characterized in that the controllable rectifier is implemented with or without feedback capability.
15. A drive system according to any one of the preceding claims, characterized in that a controllable semiconductor switch is arranged in the DC/DC converter as a regulating element for the current coming out at the direct voltage side connection of the controllable rectifier, which controllable semiconductor switch is controlled by means of a pulse-width modulated control signal generated by a current controller, which is suitably designed to regulate the current to a target value for the regulating variable used as a voltage controller.

Description

Method for operating a drive system and drive system for carrying out the method Technical Field The invention relates to a method for operating a drive system and to a drive system for carrying out the method. Background It is known to arrange intermediate circuit capacitors in the intermediate circuit of a current transformer for buffering load peaks. Disclosure of Invention It is therefore an object of the present invention to increase the durable operating time of a drive system comprising an energy store. According to the invention, this object is achieved by a method according to the features given in claim 1 and a drive system according to the features given in claim 13. In a method for operating a drive system, the important feature of the invention is that the drive system has a controllable rectifier, in particular a rectifier connected downstream to a DC/DC (direct current/direct current) converter, which can be supplied by an ac power supply system, an energy store, in particular a capacitor module, being connected to a direct voltage-side connection of the rectifier and to a direct voltage-side connection of an inverter, Wherein the controller, in particular the PI controller, determines the current as a regulating variable such that the detected voltage, in particular the intermediate circuit voltage, present at the DC voltage-side connection, is set to the target voltage U_Soll, Wherein a current which is limited, in particular by a limiting element connected downstream of the controller, to be within an upper limit value is provided at the DC voltage-side connection of the controllable rectifier, which current is supplied in particular to the energy store and to the DC voltage-side connection of the inverter connected in parallel to the energy store, Wherein the upper Limit value is determined as the quotient of a Limit value (Limit) and the detected voltage present at the DC voltage-side connection, Wherein the Limit value (Limit) is determined as a function of the temperature detected at or in the energy store and of the power P_Last supplied to the inverter at the DC voltage-side connection of the inverter, In particular, the Limit value (Limit) is the maximum value of the electrical power transmitted by the controllable rectifier from the ac power network to the dc voltage-side connection of the controllable rectifier. The advantage here is that the thermal load of the energy store is reduced by drawing less current from the energy store when the temperature of the energy store is too high. This is because, as a result, the power loss in the region of the energy store is reduced and, as a result, the thermal load of the energy store is also reduced, which assists in cooling the energy store. That is, according to the present invention, in order to perform temperature control, an influence is exerted on the charging current of the accumulator. The thermal protection of the energy store is thereby of higher value than the electrical damping function of the energy store. By this thermal protection, the ageing of the energy store is delayed, and the durable operating time of the drive system is increased. The energy store is used as a buffer store in an intermediate circuit of a drive system which can be supplied by an ac power supply system via a controllable rectifier and has an inverter which can be supplied by the intermediate circuit and which feeds the motor. In an advantageous embodiment, the temperature T in or on the energy store is detected and, if the second temperature threshold T2 is exceeded, the cooling mode is activated, and if the temperature is below the first temperature threshold T1, the cooling mode is deactivated, in particular switched off. This has the advantage that the cooling mode can be activated in the event of an excessively high temperature. By making the second temperature threshold larger than the first temperature threshold, a stable control behavior is achieved. I.e. instability is avoided. In particular, the cooling air flow is conveyed by the fan on or in the accumulator when the cooling mode is activated, and the fan is turned off when the cooling mode is deactivated. In particular, the fan is switched on in the event of an excessive temperature. In an advantageous embodiment, in the motor mode of the electric machine, if the power p_last of the inverter input at the dc voltage-side connection of the inverter is greater than a preset power Limit value p_lim, the Limit value (Limit) is set equal to the load power, provided that In the event of an activated cooling mode, the detected accumulator temperature T exceeds a first temperature threshold T1, Or in case the cooling mode is deactivated, the detected accumulator temperature T exceeds the second temperature threshold T2. In this case, the advantage is that the inverter is supplied from the ac power supply system substantially completely via the controllable rectifier in the event of excessive temperat