Power supply device and method for operating a power supply device

Abstract

The invention relates to a power supply device (SVV), in particular a switched-mode power supply unit, for generating a supply voltage at an output of the power supply device (SVV) from a three-phase alternating voltage (U_3PH) which is applied at an input of the power supply device (SVV) and comprises three phases (L1, L2, L3), said power supply device comprising: - a power section (LT), comprising: - a rectifier (GR) which is designed to convert the alternating voltage (U_3PH) into a rectified input voltage (U_IN); and - a first power sub-stage (LTS1) which is designed to convert the rectified input voltage (U_IN) into the intermediate circuit voltage (U_ZK); - and a control circuit (RS) which is designed to control the power section (LT), comprising: - a first controller (REG1) which is designed to determine, from a first control difference between a first reference variable (FG1) and a first controlled variable (RG1), a first manipulated variable (SG1) for controlling the power section (LT), wherein controller parameters of the first controller (REG1) can be changed; and - a phase monitoring unit (PÜE) which is designed to detect a failure of a phase (L1, L2, L3); - wherein the control circuit is designed to change the controller parameters of the first controller (REG1) if a failure of a phase (L1, L2, L3) is detected by means of the phase monitoring unit (PÜE).

Description

[0001] Power supply device and method for operating a

[0002] Power supply device

[0003] The invention relates to a power supply device and a method for operating a power supply device.

[0004] A power supply device, for example a switched-mode power supply, which is intended for use in a three-phase AC network or a three-phase current network, should be able to continue running even if one phase fails, with the highest possible output power or, if possible, rated power being available so that a system supplied by the power supply device or switched-mode power supply does not come to a complete standstill. Dynamic changes at the output of the power supply device or switched-mode power supply, for example load surges, should not adversely affect the connected loads.

[0005] Previously, the loss of a phase led to limited performance of the power supply or switched-mode power supply. This meant that, in the event of a phase failure, only reduced power could be drawn from the three-phase network at the output of the power supply. Due to the high currents that occur in the power section when a phase fails, winding materials, particularly inductors, with a high current-carrying capacity, especially with regard to saturation behavior, had to be used.

[0006] The object of the invention is to provide a power supply device which has high availability, high efficiency and high dynamics, and which also meets high harmonic requirements, ensures protection of the components contained therein and is compact and cost-effective. The object of the invention is also to provide a method for operating a power supply device which ensures high availability of the power supply device, ensures high efficiency and high dynamics of the power supply device and ensures that the power supply device meets high harmonic requirements and also protects the components of the power supply device and enables cost-effective and compact dimensioning of the power supply device.

[0007] The object is achieved according to the independent main claim 1 by a power supply device, in particular a switching power supply, for converting a three-phase alternating voltage applied to an input of the power supply device, which comprises three phases, comprising:

[0008] - a performance component comprising:

[0009] - a rectifier configured to convert the alternating voltage into a rectified input voltage; and

[0010] - a first power stage designed to convert the rectified input voltage into an intermediate circuit voltage;

[0011] - and a control circuit designed to control the power section, comprising:

[0012] - a first controller which is designed to determine a first manipulated variable for controlling the power section from a first control difference between a first reference variable and a first controlled variable, wherein controller parameters of the first controller are variable; and

[0013] - a phase monitoring unit designed to detect a phase failure;

[0014] - wherein the control circuit is designed to change the controller parameters of the first controller in the event of a phase failure detected by the phase monitoring unit.

[0015] The power supply device can also be used in particular for

[0016] Serve to generate a supply voltage at an output of the power supply device, wherein the power supply device can be designed to generate the supply voltage in the form of an intermediate circuit voltage or an output voltage.

[0017] The supply voltage represents a usable voltage that is made available at an output of the power supply device. If the power supply device is designed without a second power stage, then the intermediate circuit voltage represents the supply voltage. Thus, this design variant can supply a voltage intermediate circuit. If the power supply device is designed with a second power stage, then the output voltage of the second power stage represents the supply voltage. The intermediate circuit voltage and the output voltage are preferably each direct voltages.

[0018] In normal operation, i.e., in three-phase operation, a constant power can be drawn from the three-phase network, resulting in a supply voltage, e.g., an intermediate circuit voltage or an output voltage, exhibiting virtually no ripple. However, if one of the three phases of the three-phase network fails, i.e., two-phase operation occurs, a constant power can no longer be drawn from the network, resulting in a higher voltage ripple in the supply voltage, e.g., the intermediate circuit voltage or the output voltage.

[0019] For this reason, the controller parameters of the first controller, for example the controller parameters kp, ki and TI of a Type II controller or PITL controller, are changed or switched over in two-phase operation, i.e. in the event of a phase failure in the three-phase network. The first controller, for example a voltage regulator, is set more slowly. This ensures that the first controller does not try to compensate for the higher ripple of the supply voltage, e.g. the intermediate circuit voltage or the output voltage. The first controlled variable can be the intermediate circuit voltage. The first reference variable can be a setpoint for the intermediate circuit voltage. The first manipulated variable can be a manipulated variable for the power section, which corresponds, for example, to the switch-on times, the pulse width or the period of the electrical switching elements, e.g.of the transistors in the power section, or a possible current setpoint, which in turn can serve as a reference variable for a possible subordinate second controller.

[0020] It is advantageous if the control circuit is designed to change the controller parameters in such a way that a reaction speed of the first controller to changes in the first control difference is reduced compared to a three-phase operation.

[0021] This change is particularly advantageous because it means the first regulator remains stable and the currents in the power section do not increase. This is because the first regulator no longer attempts to compensate for the ripple in the supply voltage, e.g. the intermediate circuit voltage or the output voltage, since no energy can be drawn from the now 2-phase AC voltage network in the region of the zero crossings of the rectified input voltage. The measures according to the invention make it possible to use an inductance with the smallest possible saturation current. This is particularly advantageous for achieving the smallest possible size for the power supply device.

[0022] It is advantageous if the control circuit further comprises a second controller which is designed to determine a second manipulated variable for controlling the power section from a second control difference between a second reference variable and a second controlled variable, wherein the control circuit is designed to form the second control difference and to use the first manipulated variable as the second reference variable in the event of no failure of a phase detected by the phase monitoring unit.

[0023] This form of control represents cascaded control and enables the power supply device to react more quickly to disturbances such as load changes, since a second controlled variable is taken into account, which can be, for example, a current in the power section. The second manipulated variable can be a manipulated variable for the power section, in particular for the first power section stage, which corresponds, for example, to the switch-on times, the pulse width, or the period of the electrical switching elements, e.g., the transistors, in the power section, in particular in the first power section stage.

[0024] It is advantageous if the power section comprises a second power section stage which is designed to convert the intermediate circuit voltage into an output voltage, and that the control circuit further comprises a pilot control unit which is designed to detect an output power of the second power section stage and the intermediate circuit voltage and to determine a pilot control value therefrom, wherein the control circuit is designed to

[0025] - to form a first manipulated variable with a pre-tax value as the sum of the first manipulated variable and the pre-tax value; and

[0026] - in the event of a phase failure detected by the phase monitoring unit, to use the first control variable with a pre-control value as the second reference variable to form the second control difference.

[0027] The pilot control unit corresponds to a pilot control in the control engineering sense. Using the pilot control value, the second controller, whose controller parameters remain unchanged, can already adjust the second manipulated variable and thus provide the required current at the output of the first power stage before the intermediate circuit voltage deviates from the value specified by the first reference variable, e.g., the setpoint of the intermediate circuit voltage.

[0028] These features ensure very high dynamics in the first power stage even if one phase of the three-phase AC voltage fails. This means that dynamic changes at the output of the power supply device are corrected very quickly by the first power stage. This ensures minimal deviations of the intermediate circuit voltage from the specified first reference variable or from the specified setpoint of the intermediate circuit voltage. These deviations can be corrected by the second power stage without any special measures, so that the loads connected to the output are not affected. This means that if one phase of the three-phase AC voltage fails, the full power can still be drawn from the output of the power supply device, ensuring high availability of the load supplied by the power supply device.

[0029] It is advantageous if the control circuit further comprises a power detection unit which is designed to

[0030] - to measure the output voltage and an output current of the second power stage;

[0031] - to determine the output power; and

[0032] - to provide the output power of the pilot control unit.

[0033] This measure enables a particularly efficient determination of the output power.

[0034] It is advantageous if the control circuit further comprises a modulation unit which is designed to

[0035] - to detect the rectified input voltage; and - to modulate the first manipulated variable or any first manipulated variable with a pilot control value synchronously with the rectified input voltage and thus to form a modulated first manipulated variable or any first modulated manipulated variable with a pilot control value; wherein the control circuit is designed to use the modulated first manipulated variable or any first modulated manipulated variable with a pilot control value as the second reference variable in the event of a phase failure detected by the phase monitoring unit to form the second control difference.

[0036] These features prevent excessive peak currents from occurring in the first power stage or in the DC / DC converter in the event of a phase failure, thereby enabling the use of an inductor with the smallest possible saturation current and preventing damage to components. This is essential for keeping the power supply unit as small as possible. It also helps reduce costs. In addition, by modulating the first manipulated variable SGI in two-phase operation, the smallest possible effective value of the input current is achieved, thus minimizing losses in the first power stage, in the rectifier and in any upstream filter.In addition, by modulating the first manipulated variable, the quasi-resonant operation of a DC / DC converter, in which the electronic switches are always switched on at a minimum of the voltage applied to them, can be ensured even in the event of a phase failure, thereby keeping losses to a minimum. All of these loss-minimising measures mean that the highest possible power can be made available at the output of the power supply device, even in the event of a phase failure. This, in turn, increases operational reliability when using the power supply device, since a system supplied by the power supply device does not come to a complete standstill even in the event of a fault, i.e., in the event of a phase failure.It is advantageous if the control circuit is designed to form an average value of the rectified input voltage and to provide it to the modulation unit, and that the modulation unit is further designed to.

[0037] - to record an average value of the rectified input voltage provided by the control circuit,

[0038] - to form a modulation factor by dividing the rectified input voltage by the mean value of the rectified input voltage, and

[0039] - to modulate the first manipulated variable or any first manipulated variable with a pre-control value by multiplying it by the modulation factor.

[0040] This measure enables a particularly efficient modulation of the first manipulated variable.

[0041] The problem is also solved according to independent main claim 8 by a method for operating a power supply device. Further advantageous solutions to the problem arise from subclaims 9 to 14.

[0042] In the following, the invention is described and explained in more detail with reference to the exemplary embodiments shown in the figures.

[0043] Examples include:

[0044] Fig. 1: A schematic structure of an exemplary first embodiment of a power supply device according to the invention,

[0045] Fig. 2: A schematic structure of an exemplary second embodiment of a power supply device according to the invention,

[0046] Fig. 3: A schematic structure of an exemplary third embodiment of a power supply device according to the invention, Fig. 4: A schematic structure of an exemplary fourth embodiment of a power supply device according to the invention,

[0047] Fig. 5: An exemplary time profile of a rectified input voltage and an average value of an internal voltage of the power section of an exemplary second embodiment of a power supply device according to the invention, and

[0048] Fig. 6: An exemplary time course of a first manipulated variable and a product of a first manipulated variable and a modulation factor of an exemplary second embodiment of a power supply device according to the invention.

[0049] Fig. 1 shows a schematic structure of an exemplary first embodiment of a power supply device SW according to the invention. The power supply device SW comprises a power section LT and a control circuit RS. The power supply device SW is supplied at its input by a three-phase alternating voltage U_3PH or by a three-phase network with the three phases LI, L2 and L3 and generates a supply voltage at an output, in this exemplary embodiment an intermediate circuit voltage U_ZK.

[0050] In this exemplary embodiment, the power section LT comprises a rectifier GR and a first power section stage LTS 1 . In this exemplary embodiment, the rectifier GR is designed as a B6 rectifier. The rectifier GR converts the three-phase alternating voltage U_3PH into a rectified input voltage U_IN. The rectified input voltage U_IN is applied to an input of the first power section stage LTS 1 . The first power section stage LTS 1 converts the rectified input voltage U_IN into a supply voltage, in this exemplary embodiment into an intermediate circuit voltage U_ZK. However, if, as shown in Fig. 1, no second power section stage LTS2 is provided, the intermediate circuit voltage U_ZK can be regarded and used as a general supply voltage directly to supply one or more consumers (not shown), and is not restricted to further use in an intermediate circuit voltage.The first power stage LTS 1 can be designed as a DC-DC converter, e.g. as a boost-buck converter or as a boost converter.

[0051] In this exemplary embodiment, the control circuit RS comprises a first controller REG1, a second controller REG2, a phase monitoring unit PÜE, a modulation unit MOE and an averaging unit MWB.

[0052] The first controller REG1 and the second controller REG2 can, for example, be designed as Type II controllers or PITL controllers with controller parameters such as, for example, kp, ki and TI. In this exemplary embodiment, the first controller REG1 is designed as a voltage regulator. The first controller REG1 determines a first manipulated variable SGI from a first control difference, which is formed by the control circuit RS, between a first reference variable FG1, which in this exemplary embodiment is a setpoint of the intermediate circuit voltage U_ZK, and a first controlled variable RG1, which in this exemplary embodiment is the intermediate circuit voltage U_ZK, which in this exemplary embodiment is the intermediate circuit voltage U_ZK. The first control difference corresponds to the first reference variable FG1 less the first controlled variable RG1.

[0053] The phase monitoring unit PÜE is designed to monitor the phases LI, L2 and L3 of the three-phase alternating voltage U_3PH and to detect a failure of a phase LI, L2 or L3. The phase monitoring by the phase monitoring unit PÜE can be carried out directly by measuring the three phase voltages of the three-phase alternating voltage U_3PH at the input of the power supply device SW or the power section LT. Alternatively, a signal within the power section LT, the first power section stage LTS1 or the second power section stage LTS2 can be measured and evaluated in order to detect a failure of a phase LI, L2 or L3. If a failure of a phase LI, L2 or L3 of the three-phase alternating voltage U_3PH is detected by the phase monitoring unit PÜE, the controller parameters of the first controller REG1 are changed.The controller parameters of the first controller REG1 can, for example, be changed directly by the phase monitoring unit PÜE, or the phase monitoring unit PÜE can initiate a change in the controller parameters via the control circuit RS using a signal. The controller parameters of the first controller REG1 are changed in such a way that the first controller REG1 becomes slower or more sluggish. This is achieved by reducing the controller parameter values. Typical controller parameters or values ​​for controller parameters for the first controller for three-phase operation are, for example, a kp of 450, a ki of 1.5, and a TI of 0.07, and for two-phase operation, for example, a kp of 25, a ki of 0.0075, and a TI of 0.005.

[0054] In this exemplary embodiment, the second controller REG2 is designed as a current controller. The second controller REG2 determines a second manipulated variable SG2 from a second control difference, which is formed by the control circuit RS, between a second reference variable FG2, which in this exemplary embodiment is a setpoint of an average current at the output of the first power stage LTS1, and a second controlled variable RG2, which in this exemplary embodiment is an average current at the output of the first power stage LTS1. In this exemplary embodiment, the second manipulated variable SG2 corresponds, for example, to the switch-on times, the pulse width, or the period length of the electrical switching elements, e.g., the transistors, in the power stage, in particular in the first power stage. The second manipulated variable SG2 is then used to regulate or control the power stage LT, in particular the first power stage LTS1.The second control deviation corresponds to the second reference variable FG2 minus the second controlled variable RG2. The second controller REG2 is subordinate to the first controller REG1. The first controller REG1 and the second controller REG2 are cascaded, or the control circuit RS is designed as a cascade control.

[0055] The control circuit RS is designed to form the second control difference between the second reference variable FG2 and the second controlled variable RG2. The control circuit RS is also designed to use the first manipulated variable SGI as the second reference variable FG2 to form the second control difference if no failure of a phase LI, L2, L3 has been detected by the phase monitoring unit PÜE (or if no failure of a phase LI, L2 or L3 has been detected by the phase monitoring unit PÜE). This is shown schematically in Fig. 1 by a switch with the switch position 3PH. The switching within the control circuit RS, shown schematically by the switch, between two-phase operation if a phase LI, L2 or L3 fails and three-phase operation in which all phases LI, L2 and L3 are available, can be influenced by the phase monitoring unit PÜE.The phase monitoring unit PÜE continuously monitors the status of phases LI, L2 and L3.

[0056] Furthermore, a modulation unit MOE is provided in this embodiment. The modulation unit MOE is designed to detect the first manipulated variable SGI, to modulate it synchronously with the rectified input voltage U_IN or to modulate it up and down and thus to form a modulated first manipulated variable SG1_MO. The modulation unit MOE is designed to modulate the first manipulated variable SGI by multiplying it by a modulation factor MOE. The modulation factor MOE is time-dependent and can also be referred to and viewed as a modulation signal. The modulation unit is designed to form the modulation factor MOE by dividing the rectified input voltage U_IN by a (time-based) mean value of the rectified input voltage U_IN_M. The time dependence of the modulation factor MOF results from the fact that the rectified input voltage U_IN is also time-dependent.The (time) mean value of the rectified input voltage U_IN_M is formed by the control circuit RS, e.g. by an averaging unit MWB, and provided by the modulation unit MOE.

[0057] The relationship is shown in Figs. 5 and 6. Fig. 5 shows the time course of the rectified input voltage U_IN and the (time) mean value of the rectified input voltage U_IN_M in the event of a failure of one of the phases LI, L2 or L3. The rectified input voltage U_IN pulsates, as shown in Fig. 5. This results from a superposition of the two remaining phase voltages of the formerly three-phase alternating voltage U_3PH, which are phase-shifted by 120°. The (time) mean value of the rectified input voltage U_IN_M is constant during one period of the rectified input voltage U_IN. Fig. 6 shows the time course of the first manipulated variable SGI and the result of the modulation by multiplying the first manipulated variable SGI by the modulation factor MOF, the result corresponding to the modulated first manipulated variable SG1_MO.The modulation factor MOF is formed as described above by dividing the rectified input voltage U_IN by the (time) average value of the rectified input voltage U_IN_M.

[0058] The control circuit RS is furthermore, as further shown in Fig. 1, designed to use the modulated first manipulated variable SG1_MO as the second reference variable FG2 to form the second control difference between the second reference variable FG2 and the second controlled variable RG2 in the event of a failure of a phase LI, L2, L3 detected by the phase monitoring unit PÜE. This is shown schematically in Fig. 1 by a switch with the switch position 2PH. By using the modulated first manipulated variable SG1_MO as the second reference variable FG2, the second controller REG2 is prevented from attempting to supply the current that would be required by an unmodulated first manipulated variable SGI by adjusting the second manipulated variable SG2, especially in the area of ​​the zeros or minima of the rectified input voltage U_IN that arise in the event of a phase LI, L2 or L3 failure.The use of the modulated first manipulated variable SG1_MO as the second reference variable FG2 thus leads to reduced currents in the first power stage LTS 1 , in particular to reduced peak current values ​​in chokes, which in this design variant are provided in the first power stage LTS 1 . Furthermore, losses in the first power stage LTS 1 , in the rectifier GR, and in any upstream filter are reduced, and high efficiency is achieved. Furthermore, harmonic requirements for the power supply device SW are met.

[0059] The control circuit RS is further designed so that when all three phases LI, L2 and L3 of the three-phase alternating voltage U_3PH are available again, i.e. when the phase monitoring unit PÜE no longer detects a failure of a phase LI, L2 or L3, the controller parameters of the first controller REG1 are switched back to three-phase operation. The first controller REG1 is then set more quickly because a constant power can now be drawn from the three-phase network again. In addition, the first manipulated variable SGI is again used as the second reference variable FG2 to form the second control difference. In this case, the modulation unit MOE is deactivated or switched off by the control circuit RS.

[0060] In this exemplary embodiment, the following process steps are carried out, among others, if the phase monitoring unit PÜE detects a failure of a phase LI, L2 or L3:

[0061] - Changing the controller parameters of the first controller REG1 by the control circuit RS, in particular in such a way that a reaction speed of the first controller REG1 to changes in the first control difference is reduced compared to a three-phase operation,

[0062] - Formation of the first control difference between the first reference variable FG1 and the first controlled variable RG1,

[0063] - Determination of a first manipulated variable SGI for controlling the power unit LT from the first control difference by the first controller REG1,

[0064] - Detection of the rectified input voltage U_IN by the modulation unit MOE,

[0065] - Forming an average value of the rectified input voltage U_IN_M by the control circuit RS and providing the average value of the rectified input voltage U_IN_M for the modulation unit MOE by the control circuit RS,

[0066] - Detecting the mean value of the rectified input voltage U_IN_M by the modulation unit MOE,

[0067] - Formation of a modulation factor MOE by dividing the rectified input voltage U_IN by the mean value of the rectified input voltage U_IN_M by the modulation unit MOE,

[0068] - Modulating the first manipulated variable SGI synchronously with the rectified input voltage U_IN by multiplying it by the modulation factor MOE and thus forming the modulated first manipulated variable SG1_MO,

[0069] - Formation of the second control difference between the second reference variable FG2 and the second controlled variable RG2 by the control circuit RS, wherein the modulated first manipulated variable SG1_MO is used as the second reference variable FG2 to form the second control difference,

[0070] - Determination of the second manipulated variable SG2 for controlling the power unit LT from the second control difference by the second controller REG2,

[0071] - Control of the power section LT, in particular the first power section stage LTS1, by means of the second manipulated variable SG2. Fig. 2 shows a schematic structure of an exemplary second embodiment of a power supply device SW according to the invention. The difference to the first embodiment shown in Fig. 1 is that the intermediate circuit voltage U_ZK is applied to an input of a second power section stage LTS2. The second power section stage LTS2 is designed to convert the intermediate circuit voltage U_ZK into the supply voltage, in this embodiment an output voltage U_OUT, which is provided at an output of the second power section stage LTS2 or an output of the power section LT. The second power section stage LTS2 can, for example, be a converter, in particular a resonant converter or LLC resonant converter.

[0072] Fig. 3 shows a schematic structure of an exemplary third embodiment of a power supply device according to the invention. The difference from the second embodiment is that the control circuit RS is designed differently. The control circuit RS also comprises the first controller REG1, the second controller REG2 and the phase monitoring unit PÜE. The phase monitoring unit PÜE is also designed to detect a failure of a phase LI, L2 or L3 of the three-phase alternating voltage U_3PH. The first controller REG1 is also designed to form a first manipulated variable from a first control difference formed by the control circuit RS between the first reference variable FG1 and the first controlled variable RG1. In this embodiment too, the first reference variable FG1 is the setpoint of the intermediate circuit voltage U_ZK and the first controlled variable RG1 is the intermediate circuit voltage U_ZK.The control circuit is further designed to change the controller parameters of the first controller REG1 in the event of a failure of a phase LI, L2 or L3 of the three-phase alternating voltage U_3PH detected by the phase monitoring unit PÜE. The second controller REG2 is further designed to form a second manipulated variable from a second control difference formed by the control circuit RS between the second reference variable FG2 and the second controlled variable RG2. The control circuit is further designed to use the first manipulated variable SGI as the second reference variable FG2 to form the second control difference in the event of no failure of a phase LI, L2 or L3 of the three-phase alternating voltage U_3PH detected by the phase monitoring unit PÜE.The difference to the second embodiment is that in this third embodiment the control circuit RS does not comprise a modulation unit MOE or an averaging unit MWB, but rather a pilot control unit VSE and a power recording unit LEE. The pilot control unit VSE is a control unit in the control engineering sense. The pilot control unit VSE is designed to record an output power P_OUT of the second power stage LTS2 and the intermediate circuit voltage U_ZK and to determine a pilot control value VSW from this. The pilot control value VSW is determined, for example, by dividing the output power P_OUT by the intermediate circuit voltage U_ZK.The control circuit RS is designed to form a first manipulated variable SGI ' with a pre-control value as the sum of the first manipulated variable SGI and the pre-control value VSW and, in the event of a failure of a phase LI, L2 or L3 detected by the phase monitoring unit PÜE, to use the first manipulated variable SGI ' with a pre-control value as the second reference variable to form the second control difference.

[0073] (FG2). The pre-control value VSW can be continuously generated by the pre-control unit VSE and only switched on to form the sum in the event of a failure of a phase LI, L2 or L3 detected by the phase monitoring unit PÜE, as shown in Fig. 3 by a switch influenced by the phase monitoring unit PÜE and schematically illustrated. Alternatively, the pre-control unit VSE can only be activated in the event of a failure of a phase LI, L2 or L3 detected by the phase monitoring unit PÜE. When the pre-control unit VSE is switched on or activated, the integrating component of the first regulator REG1, which in this embodiment is a voltage regulator, is set to zero once, since when the pre-control unit VSE is active the first regulator REG1 only has to correct the deviations of the pre-control unit VSE, which are generally very small.Thanks to the pre-control value VSW, the second controller REG2, which in this exemplary embodiment is a current controller whose parameters remain unchanged, can already adjust the second manipulated variable SG2 and provide the required current at the output of the first power stage LTS 1 before the intermediate circuit voltage U_ZK deviates from the setpoint of the intermediate circuit voltage. This measure enables the first power stage LTS 1 to exhibit a high level of dynamic response.

[0074] In this exemplary embodiment, the control circuit RS further comprises a power detection unit LEE which is designed to detect the output voltage U_OUT and an output current I_OUT of the second power stage LTS2, to determine the output power P_OUT therefrom and to provide the output power P_OUT to the pilot control unit VSE.

[0075] The control circuit RS is further designed so that when all three phases LI, L2 and L3 of the three-phase alternating voltage U_3PH are available again, i.e. when the phase monitoring unit PÜE no longer detects a failure of a phase LI, L2 or L3, the controller parameters of the first controller REG1 are switched back to three-phase operation. The first controller REG1 is then set more quickly because a constant power can now be drawn from the three-phase network. In addition, the first manipulated variable SGI is again used as the second reference variable FG2 to form the second control difference. In this case, the pilot control unit VSE is deactivated or switched off by the control circuit RS. In this exemplary embodiment, the following process steps are therefore carried out, among others, if the phase monitoring unit PÜE detects a failure of a phase LI, L2 or L3:

[0076] - Changing the controller parameters of the first controller REG1 by the control circuit RS, in particular in such a way that a reaction speed of the first controller REG1 to changes in the first control difference is reduced compared to a three-phase operation,

[0077] - Formation of the first control difference between the first reference variable FG1 and the first controlled variable RG1,

[0078] - Determination of the first manipulated variable SGI for controlling the power unit LT from the first control difference by the first controller REG1,

[0079] - Detection of the output voltage U_OUT and the output current I_OUT of the second power stage LTS2 by the power detection unit LEE,

[0080] - Determining the output power P_OUT of the second power stage LTS2 from the output voltage U_OUT and the output current I_OUT by the power measurement unit LEE,

[0081] - Providing the output power P_OUT for the pilot control unit VSE by the control circuit RS,

[0082] - Detection of the output power P_OUT and the intermediate circuit voltage U_ZK by the pilot control unit VSE,

[0083] - Determining the pre-control value VSW from the output power P_OUT and the intermediate circuit voltage U_ZK, in particular by dividing the output power P_OUT by the intermediate circuit voltage U_ZK, by the pre-control unit VSE,

[0084] - Formation of the first manipulated variable SGI ' with a pre-control value as the sum of the first manipulated variable SGI and the pre-control value VSW by the control circuit RS,

[0085] - Formation of the second control difference between the second reference variable FG2 and the second controlled variable RG2 by the control circuit RS, wherein the first control variable SGI ' with a pre-control value is used as the second reference variable FG2 to form the second control difference,

[0086] - Determination of the second manipulated variable SG2 for controlling the power unit LT from the second control difference by the second controller REG2,

[0087] - Control of the power section LT , in particular the first power section stage LTS 1 , by the second manipulated variable SG2 .

[0088] Fig. 4 shows a schematic structure of an exemplary fourth embodiment of a power supply device according to the invention. This embodiment represents a combination of the second and third embodiments, in which the control circuit RS comprises the modulation unit MOE and the averaging unit as well as the pilot control unit VSE and the power detection unit LEE. In this embodiment, the technical effects and advantages of the second and third embodiments are advantageously combined, so that the power supply device SW in this embodiment has high dynamics and low losses and meets high requirements for the harmonic characteristics.

[0089] The control circuit RS is designed to activate or switch on both the modulation unit MOE and the pilot control unit VSE if the phase monitoring unit PÜE detects a failure of a phase LI, L2 or L3. The first manipulated variable SGI formed by the first controller REG1 is first subjected to a pilot control value VSW formed by the pilot control unit VSE. From this first manipulated variable SGI ' with a pilot control value, the modulation unit MOE then creates a modulated first manipulated variable SGI '_MO with a pilot control value. The control circuit RS is designed to use the modulated first manipulated variable SGI '_MO with a pilot control value to form the second control difference as the second reference variable FG2.In this exemplary embodiment, the following process steps are carried out, among others, if the phase monitoring unit PÜE detects a failure of a phase LI, L2 or L3:.

[0090] - Changing the controller parameters of the first controller REG1 by the control circuit RS, in particular in such a way that a reaction speed of the first controller REG1 to changes in the first control difference is reduced compared to a three-phase operation,

[0091] - Formation of the first control difference between the first reference variable FG1 and the first controlled variable RG1,

[0092] - Determination of the first manipulated variable SGI for controlling the power unit LT from the first control difference by the first controller REG1,

[0093] - Detection of the output voltage U_OUT and the output current I_OUT of the second power stage LTS2 by the power detection unit LEE,

[0094] - Determining the output power P_OUT of the second power stage LTS2 from the output voltage U_OUT and the output current I_OUT by the power measurement unit LEE,

[0095] - Providing the output power P_OUT for the pilot control unit VSE by the control circuit RS,

[0096] - Detection of the output power P_OUT and the intermediate circuit voltage U_ZK by the pilot control unit VSE,

[0097] - Determining the pre-control value VSW from the output power P_OUT and the intermediate circuit voltage U_ZK, in particular by dividing the output power P_OUT by the intermediate circuit voltage U_ZK, by the pre-control unit VSE,

[0098] - Formation of the first manipulated variable SGI ' with a pre-control value as the sum of the first manipulated variable SGI and the pre-control value VSW by the control circuit RS,

[0099] - detecting the rectified input voltage U_IN by the modulation unit MOE, - forming an average value of the rectified input voltage U_IN_M by the control circuit RS and providing the average value of the rectified input voltage U_IN_M for the modulation unit MOE by the control circuit RS,

[0100] - Detecting the mean value of the rectified input voltage U_IN_M by the modulation unit MOE,

[0101] - Formation of a modulation factor MOE by dividing the rectified input voltage U_IN by the mean value of the rectified input voltage U_IN_M by the modulation unit MOE,

[0102] - Modulating the pre-control value-dependent first manipulated variable SGI ' synchronously with the rectified input voltage U_IN by multiplying it by the modulation factor MOE and thus forming the modulated pre-control value-dependent first manipulated variable SGI '_M0,

[0103] - Formation of the second control difference between the second reference variable FG2 and the second controlled variable RG2 by the control circuit RS, wherein the pre-control value-dependent modulated first manipulated variable SGI '_M0 is used as the second reference variable FG2 to form the second control difference,

[0104] - Determination of the second manipulated variable SG2 for controlling the power unit LT from the second control difference by the second controller REG2,

[0105] - Control of the power section LT , in particular the first power section stage LTS 1 , by the second manipulated variable SG2 .

[0106] In all design variants, the values, quantities, factors or signals, such as the first control difference, the second control difference, the first manipulated variable SGI, the second manipulated variable SG2, the pre-control value VSW, the modulation factor MOE or the mean value of the rectified input voltage U_IN_M, are determined, calculated or formed continuously or at discrete time intervals and thus a continuous control of the power section LT is carried out by the control circuit RS. According to the invention, it is also possible not to carry out cascaded control with a first controller REG1 and a second controller REG2, but rather to use only a first controller REG1. The first manipulated variable SGI then corresponds to the switch-on times, the pulse width or the period of the electrical switching elements, for example the transistors, in the power section LT or in the first power section stage LTS1.

Claims

Patent claims 1. Power supply device (SW), in particular a switching power supply, for converting a three-phase alternating voltage (U_3PH) applied to an input of the power supply device (SW), which comprises three phases (LI, L2, L3), comprising: - a power unit (LT) comprising: - a rectifier (GR) designed to convert the alternating voltage (U_3PH) into a rectified input voltage (U_IN); and - a first power stage (LTS1) designed to convert the rectified input voltage (U_IN) into an intermediate circuit voltage (U_ZK); - and a control circuit (RS) designed to control the power section (LT), comprising: - a first controller (REG1) which is designed to determine a first manipulated variable (SGI) for controlling the power unit (LT) from a first control difference between a first reference variable (FG1) and a first controlled variable (RG1), wherein controller parameters of the first controller (REG1) are variable; and - a phase monitoring unit (PÜE) designed to detect a failure of a phase (LI, L2, L3); - wherein the control circuit (RS) is designed to change the controller parameters of the first controller (REG1) in the event of a failure of a phase (LI, L2, L3) detected by the phase monitoring unit (PÜE).

2. Device according to claim 1, characterized in that the control circuit (RS) is designed to change the controller parameters in such a way that a reaction speed of the first controller (REG1) to changes in the first control difference is reduced compared to a three-phase operation.

3. Device according to one of claims 1 or 2, characterized in that the control circuit (RS) further comprises a second controller (REG2) which is designed to determine a second manipulated variable (SG2) for controlling the power section (LT) from a second control difference between a second reference variable (FG2) and a second controlled variable (RG2), wherein the control circuit (RS) is designed to form the second control difference and in doing so to use the first manipulated variable (SGI) as the second reference variable (FG2) in the event of no failure of a phase (LI, L2, L3) detected by the phase monitoring unit (PÜE).

4. Device according to claim 3, characterized in that the power section (LT) comprises a second power section stage (LTS2) which is designed to convert the intermediate circuit voltage (U_ZK) into an output voltage (U_OUT), and in that the control circuit (RS) further comprises a pre-control unit (VSE) which is designed to detect an output power (P_OUT) of the second power section stage (LTS2) and the intermediate circuit voltage (U_ZK) and to determine a pre-control value (VSW) therefrom, wherein the control circuit (RS) is designed to - to form a first manipulated variable (SGI') with a pre-control value as the sum of the first manipulated variable (SGI) and the pre-control value (VSW); and - in the event of a phase failure (LI, L2, L3) detected by the phase monitoring unit (PÜE), to use the first manipulated variable (SGI') with a pre-control value as the second reference variable (FG2) to form the second control difference.

5. Device according to claim 4, characterized in that the control circuit (RS) further comprises a power detection unit (LEE) which is designed to - to measure the output voltage (U_OUT) and an output current (I_OUT) of the second power stage (LTS2); - to determine the output power (P_OUT) from this; and - to provide the output power (P_OUT) of the pilot control unit (VSE).

6. Device according to one of claims 3 to 5, characterized in that the control circuit (RS) further comprises a modulation unit (MOE) which is designed to - to measure the rectified input voltage (U_IN); and - to modulate the first manipulated variable (SGI) or any first manipulated variable (SGI') with a pilot control value synchronously with the rectified input voltage (U_IN) and thus to form a modulated first manipulated variable (SG1_MO) or any modulated first manipulated variable (SG1'_MO) with a pilot control value; wherein the control circuit (RS) is designed to use the modulated first manipulated variable (SG1_MO) or any first manipulated variable (SG1'_MO) with a pilot control value as the second reference variable (FG2) in the event of a phase (LI, L2, L3) failure detected by the phase monitoring unit (PÜE) to form the second control difference.

7. Device according to claim 6, characterized in that the control circuit (RS) is designed to form an average value of the rectified input voltage (U_IN_M) and to provide it to the modulation unit (MOE), and that the modulation unit (MOE) is further designed to - to record an average value of the rectified input voltage (U_IN_M) provided by the control circuit (RS), - a modulation factor (MOE) by dividing the rectified input voltage (U_IN) by the mean value of the rectified input voltage (U_IN_M) and - to modulate the first manipulated variable (SGI) or any first manipulated variable (SGI') with a pre-control value by multiplying it by the modulation factor (MOE).

8. Method for operating a power supply device (SW) according to one of claims 1 to 7, in particular a switched-mode power supply, for converting a three-phase alternating voltage (U_3PH) applied to an input of the power supply device (SW), which comprises three phases (LI, L2, L3), comprising: - a power unit (LT) comprising: - a rectifier (GR) which converts the alternating voltage (U_3PH) into a rectified input voltage (U_IN); and - a first power stage (LTS1) which converts the rectified input voltage (U_IN) into the intermediate circuit voltage (U_ZK); - and a control circuit (RS) which controls the power section (LT), comprising: - a first controller (REG1), wherein controller parameters of the first controller (REG1) are variable; and - a phase monitoring unit (PÜE); the following further process steps are carried out: - Changing the controller parameters of the first controller (REG1) by the control circuit (RS) if the phase monitoring unit (PÜE) has detected a failure of a phase (LI, L2, L3); - Determining a first manipulated variable (SGI) for controlling the power section (LT) from a first control difference between a first reference variable (FG1) and a first controlled variable (RG1) by the first controller (REG1).

9. The method according to claim 8, characterized in that the control circuit (RS) changes the controller parameters in such a way that a reaction speed of the first controller (REG1) to changes in the first control difference is reduced compared to a three-phase operation.

10. Method according to one of claims 8 or 9, characterized in that the control circuit (RS) further comprises a second controller (REG2); wherein the following further method steps are carried out: - Formation of a second control difference between a second reference variable (FG2) and a second controlled variable (RG2) by the control circuit (RS), wherein the first manipulated variable (SGI) is used as the second reference variable (FG2) to form the second control difference if no failure of a phase (LI, L2, L3) was detected by the phase monitoring unit (PÜE); - Determining a second manipulated variable (SG2) for controlling the power unit (LT) from the second control difference by the second controller (REG2).

11. The method according to claim 10, characterized in that the power section (LT) further comprises a second power section stage (LTS2) which converts the intermediate circuit voltage (U_ZK) into an output voltage (U_OUT), and the control circuit (RS) further comprises a pilot control unit (VSE); wherein the following further method steps are carried out: - Detection of an output power (P_OUT) of the second power stage (LTS2) and the intermediate circuit voltage (U_ZK) by the pilot control unit (VSE); - Determination of a pre-control value (VSW) from the output power (P_OUT) and the intermediate circuit voltage (U_ZK) by the pre-control unit (VSE); - Formation of a first manipulated variable (SGI') with a pre-control value as the sum of the first manipulated variable (SGI) and the pre-control value (VSW) by the control circuit (RS); - Formation of the second control difference between the second reference variable (FG2) and the second controlled variable (RG2) by the control circuit (RS), wherein the first control variable (SGI') with a pre-control value is used as the second control variable (FG2) to form the second control difference, if a failure of a phase (LI, L2, L3) has been detected by the phase monitoring unit (PÜE); and - Determining a second manipulated variable (SG2) for controlling the power unit (LT) from the second control difference by the second controller (REG2).

12. Method according to claim 11, characterized in that the control circuit (RS) further comprises a power detection unit (LEE); wherein the following further method steps are carried out: - Detecting the output voltage (U_OUT) and an output current (I_OUT) of the second power stage (LTS2) by the power detection unit (LEE); - Determining the output power (P_OUT) of the second power stage (LTS2) from the output voltage (U_OUT) and the output current (I_OUT) by the power detection unit (LEE); and - Providing the output power (P_OUT) for the pilot control unit (VSE) through the control circuit (RS) .

13. Method according to one of claims 10 to 12, characterized in that the control circuit (RS) further comprises a modulation unit (MOE), wherein the following further method steps are carried out: - Detection of the rectified input voltage (U_IN) by the modulation unit (MOE); - Modulating the first manipulated variable (SGI) or any first manipulated variable (SGI') with a pre-control value synchronously with the rectified input voltage (U_IN) and thus forming a modulated first manipulated variable (SG1_MO) or any first manipulated variable (SG1'_MO) with a pre-control value modulated; - Formation of the second control difference between the second reference variable (FG2) and the second controlled variable (RG2) by the control circuit (RS), wherein the modulated first manipulated variable (SG1_MO) or any modulated pre-control value-dependent first manipulated variable (SG1'_MO) is used as the second control variable (FG2) to form the second control difference, if a failure of a phase (LI, L2, L3) has been detected by the phase monitoring unit (PÜE); and - Determining a second manipulated variable (SG2) for controlling the power unit (LT) from the second control difference by the second controller (REG2).

14. Method according to claim 13, characterized in that the following further method steps are carried out: - Forming an average value of the rectified input voltage (U_IN_M) by the control circuit (RS) and providing the average value of the rectified input voltage (U_IN_M) for the modulation unit (MOE) by the control circuit (RS), - Detection of the mean value of the rectified input voltage (U_IN_M) by the modulation unit (MOE), - Forming a modulation factor (MOE) by dividing the rectified input voltage (U_IN) by the mean value of the rectified input voltage (U_IN_M) by the modulation unit (MOE), - Modulating the first manipulated variable (SGI) or any first manipulated variable (SGI') with a pre-control value by multiplying it by the modulation factor (MOE) by the modulation unit (MOE).

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