Method for generating a control signal for pulse width modulation, converter and computer program product

Abstract

A method is disclosed comprising: receiving a voltage request (102); generating a first signal (112); generating a second signal (114); selecting one of the first signal (112) and the second signal (114) as the selected signal (121); and generating a control signal (132) for pulse-width modulation based on the voltage request (102) and the selected signal (121). A converter and a computer program product are also disclosed.

Description

Description TECHNICAL AREA

[0001] The present disclosure relates to the field of pulse width modulation. BACKGROUND

[0002] An article entitled “A High-Performance Generalized Discontinuous PWM Algorithm” in IEEE Transactions on Industry Applications, Vol. 34, No. 5, pages 1059-1071, describes a discontinuous pulse width modulation method.

[0003] DE 100 19 374 C2 discloses a control method for a pulse width controlled converter with controllable power semiconductor switches for reducing switching losses while avoiding noise generation. SUMMARY

[0004] Given the situation described above, there may be a need for a technique that allows a method for generating a control signal for pulse width modulation and a corresponding converter with improved characteristics to be provided.

[0005] This need can be met by the independent claims. Some advantageous embodiments are specified in the dependent claims.

[0006] According to a first aspect of the items disclosed herein, a procedure is provided.

[0007] According to an embodiment of the first aspect, a method is provided comprising: receiving a voltage request; generating a first signal; generating a second signal; selecting one of the first signal and the second signal as the selected signal; generating a control signal for pulse width modulation based on the voltage request and the selected signal, wherein the selection of the first signal or the second signal is based on a difference between the first signal and the second signal.

[0008] According to a second aspect of the items disclosed herein, a converter is provided.

[0009] According to one embodiment of the second aspect, a converter is provided, the converter comprising a control device, wherein the control device is configured to receive a voltage request; wherein the control device is configured to generate a first signal and to generate a second signal; wherein the control device is configured to select one of the first signal and the second signal as the selected signal based on a difference between the first signal and the second signal; and wherein the control device is configured to generate a control signal for pulse width modulation based on the voltage request and the selected signal.

[0010] According to a third aspect of the items disclosed herein, a computer program product is provided.

[0011] According to one embodiment of the third aspect, a computer program product is provided, the computer program product comprising a program element which is configured to control a method according to the first aspect when executed on a processor device. DESCRIPTION OF EXEMPLARY FORMS

[0012] Even though certain disadvantages of earlier technologies are mentioned herein, the claimed subject matter is not to be limited to implementations that overcome some or all of the mentioned disadvantages of the earlier technologies. Furthermore, even though certain advantages of the subject matter disclosed herein are mentioned or implied in the present disclosure, the claimed subject matter is not to be limited to implementations that exhibit some or all of these advantages.

[0013] Exemplary embodiments of the items disclosed herein are described below, with reference, for example, to a method, a converter, and a computer program product. It should be emphasized that, of course, any combination of features of different aspects, embodiments, and examples is possible. In particular, some embodiments are described with reference to a method, while other embodiments are described with reference to a computer program product. Still other embodiments are described with reference to a device, in particular a converter, while other embodiments are described with reference to a control device for interacting with elements of the device.However, the person skilled in the art will understand from the foregoing and following description, the claims, and the drawings that, unless otherwise stated, features of different aspects, embodiments, and examples can be combined, and such combinations of features are to be considered disclosed herein. For example, even a feature relating to a method can be combined with a feature relating to a device, and vice versa.

[0014] Exemplary implementations of the items disclosed herein include, in particular, one or more of the embodiments and combinations of embodiments described herein.

[0015] A method according to the first aspect is, according to one embodiment, a method for generating a control signal for pulse-width modulation. According to one embodiment, the method includes receiving a voltage command, for example, a voltage command detected by a current controller. According to another embodiment, the method includes generating a first signal and a second signal. For example, the first signal is a first injection signal and the second signal is a second injection signal. According to one embodiment, an injection signal such as described herein is provided to be indexed into another signal.

[0016] According to another embodiment, the method includes selecting one of the first and second signals as the selected signal. In one embodiment, the selection is performed using a selection criterion. In other words, according to one embodiment, the method is configured to select either the first or the second signal as the selected signal using a selection criterion. According to another embodiment, the method includes generating a control signal for pulse-width modulation using the selected signal, for example, based on the voltage requirement and the selected signal.

[0017] A converter according to the second aspect is, in one embodiment, a converter comprising a control device. In one embodiment, the control device is configured to receive a voltage request. In another embodiment, the control device is configured to generate a first signal and a second signal. In yet another embodiment, the control device is configured to select one of the first and second signals as the selected signal using a selection criterion. In yet another embodiment, the control device is configured to generate a control signal for pulse-width modulation using the selected signal, for example, based on the voltage request and the selected signal.

[0018] A computer program product according to the third aspect is configured according to an embodiment to control a method disclosed herein, in particular a method according to at least one embodiment of the first aspect.

[0019] At least some aspects and embodiments of the subject matter disclosed herein are based on the idea that by generating a control signal for pulse-width modulation based on the voltage requirement and based on a selected signal chosen from two different signals using a selection criterion, a method for generating a control signal for pulse-width modulation with improved characteristics can be provided. In particular, according to one embodiment, the selection criterion can be configured such that a large time window for current measurement is provided over a pulse-width modulation period. The size of the available time window for current measurement can be optimized by adjusting the selection criterion (for example, in one embodiment, by setting a threshold value).For example, according to one embodiment, a time window for current measurement can be provided even at high modulation indices, since embodiments of the items disclosed herein avoid switching conflicts of the switches of an inverter operated with pulse-width modulation. In other words, embodiments of the items disclosed herein avoid disadvantages of conventional pulse-width modulation methods, in particular the disadvantage that the available time window for current measurement shrinks when the modulation index is increased (or when the voltage requirement is increased). Embodiments of the method disclosed herein allow this disadvantage to be completely overcome.

[0020] According to one embodiment, the first signal and / or the second signal is generated from the voltage request. For example, according to one embodiment, the first signal and / or the second signal is derived from a modulation index generated from the voltage request.

[0021] According to one embodiment, the selection of the first signal or the second signal as the selected signal is performed using the voltage requirement. In other words, the selection criterion uses the voltage requirement. For example, according to one embodiment, the selection of the first signal or the second signal as the selected signal is performed using at least one derived quantity derived from the voltage requirement. According to another embodiment, the selection of the first signal or the second signal is performed based on a difference between the first signal and the second signal.

[0022] According to another embodiment, the selection of the first signal or the second signal as the selected signal is carried out using a threshold value.

[0023] In a combination of the foregoing embodiments, the selection criterion according to one embodiment uses the quantity derived from the voltage requirement and the threshold value.

[0024] According to one embodiment, the voltage request is periodic and defines a period. For example, the voltage request is a sinusoidal signal, which in one embodiment is generated by a current controller.

[0025] According to another embodiment, the first signal is selected during the first part of the period and the second signal is selected during the second part of the period. In other words, during a single period of voltage demand, the control signal is generated partly using the first signal and partly using the second signal.

[0026] For example, during a single period of voltage demand according to one embodiment, at least one change of the selected signal from the first signal to the second signal, and / or vice versa, occurs.

[0027] According to one embodiment, the first signal is a third harmonic of the voltage request and / or the second signal is a third harmonic of the voltage request. In other words, the frequency of the first signal and / or the second signal is three times higher than the frequency of the voltage request.

[0028] According to one embodiment, the method or converter is configured for a multiphase system. In one embodiment, the voltage request includes a component for each phase of the multiphase system. In another embodiment, the control signal includes a component for each phase of the multiphase system. For example, the multiphase system is a three-phase system. In another embodiment, the selected signal is used for each phase of the multiphase system. In other words, the control signal for each phase is generated (for example, at each time) using the same selected signal.

[0029] According to one embodiment, the first signal and / or the second signal is derived from a component of a phase of the voltage requirement.

[0030] According to one embodiment, a minimum and a maximum value of a quantity derived from the voltage requirement are determined based on the components of the voltage requirement. For example, according to one embodiment, a minimum and a maximum value of a quantity derived from the voltage requirement are determined based on all components of the voltage requirement. The quantity derived from the voltage requirement could, for example, be a modulation index. In other words, in one embodiment, a minimum modulation index and a maximum modulation index are determined based on the (i.e., all) components of the voltage requirement (for example, among the modulation indices of the phases).

[0031] According to one embodiment, the minimum value is the first signal and the maximum value is the second signal. According to another embodiment, the selection of the first signal or the second signal as the selected signal is based (e.g., among other things) on the first signal and the second signal. For example, the selection of the first signal or the second signal as the selected signal is based on a difference between the first signal and the second signal and on a threshold value.

[0032] For example, according to one embodiment, the first signal is selected when the difference between its maximum and minimum values ​​(or the difference between the first and second signals) is greater than or equal to the threshold, and the second signal is selected when the difference between its maximum and minimum values ​​is less than the threshold. According to one embodiment, the threshold lies in an interval between 0.08 and 0.095 when compared to a difference in modulation indices (i.e., a value between 0 and 1 or a value between 0% and 100%). According to another embodiment, the threshold is 0.09 (i.e., 9%).According to one embodiment, the control signal (for example, a pulse-width modulation pattern) generated according to embodiments of the items disclosed herein ensures that no switching occurs near the current measurement point (time of current measurement). The inventors found through simulations that, surprisingly, a threshold of 9% provides a wide time window for current measurement (current measurement window). In one embodiment, the 9% threshold provides a current measurement window of maximum width. Where reference is made here to the width of the current measurement window, this width refers to the time axis; that is, a wide current measurement window provides a long duration for current measurement.According to one embodiment, a period of 9% of the pulse width modulation period (corresponding to the period of the voltage request) is always free of switching operations, thus enabling conflict-free current measurement regardless of the modulation index (for example, in a three-phase system, for two of the three phases). During this time, the current measurement window is open for at least two of the three phases (in a three-phase system), and current measurements can be performed. Unlike conventional methods, a limitation of the modulation index to enable current measurements is not required in a method according to embodiments of the subject matter disclosed herein.

[0033] According to another embodiment, values ​​other than 9% (i.e. greater than 9% or less than 9%) can be used, however, in one embodiment these result in a smaller current measurement window.

[0034] In one embodiment, the control signal controls pulse-width modulation in an inverter. In another embodiment, the inverter draws energy from a DC circuit. In one embodiment, the modulation index is defined as the quotient of the voltage requirement divided by a measured DC voltage of the DC circuit.

[0035] According to one embodiment, an intermediate signal is generated from the voltage request, and the selected signal is injected into this intermediate signal to generate the control signal. For example, according to one embodiment, the control signal is the sum of the selected signal and a derived quantity derived from the voltage request. For example, according to one embodiment, the control signal is the sum of the modulation index and the selected signal. For example, in a multiphase system, the control signal in one phase is the sum of the modulation index of that phase and the selected signal.

[0036] According to one embodiment, the program element is a non-transient program element. According to another embodiment, the computer program product is a non-transient computer program product.

[0037] As used herein, reference to a computer program product comprising a program element is considered equivalent to reference to a computer program comprising a program element and / or a computer-readable medium comprising a program element. According to one embodiment, the program element comprises instructions for controlling a processor device (comprising one or more microprocessors, for example, a computer system) to effect and / or coordinate the execution of at least one method described herein.

[0038] The (non-transient) program element can be implemented as computer-readable instruction code using any suitable programming language, such as C, C++, or assembly language, etc., and can be stored on a computer-readable medium (removable disk, volatile or non-volatile memory, embedded memory / processor, etc.). According to one embodiment, the instruction code is executable for programming a computer or any other programmable processing device to perform the intended functions. The computer program can be available on a network, such as the World Wide Web, from which it can be downloaded.

[0039] The items disclosed herein can be realized by means of a computer program product (program element) or software. However, the items disclosed herein can also be realized by one or more specific electronic circuits or hardware. Furthermore, the items disclosed herein can also be realized in hybrid form, i.e., in a combination of software modules and hardware modules.

[0040] According to one embodiment, one or more of the control devices and controllers disclosed herein may include a processor device configured to execute a program element disclosed herein.

[0041] According to embodiments of the first aspect, the method is set up to realize one or more of the embodiments disclosed herein, to provide the functionality of one or more of the embodiments disclosed herein, to provide the functionality as required for one or more of the embodiments disclosed herein, and / or to provide the functionality as required by one or more of the embodiments disclosed herein, in particular the embodiments of the first aspect, the second aspect and / or the third aspect.

[0042] According to embodiments of the second aspect, the converter is configured to implement one or more of the embodiments disclosed herein, to provide the functionality of one or more of the embodiments disclosed herein, to provide the functionality as required for one or more of the embodiments disclosed herein, and / or to provide the functionality as required by one or more of the embodiments disclosed herein, in particular the embodiments of the first aspect, the second aspect and / or the third aspect.

[0043] According to embodiments of the third aspect, the computer program product is configured to implement one or more of the embodiments disclosed herein, to provide the functionality of one or more of the embodiments disclosed herein, to provide the functionality as required for one or more of the embodiments disclosed herein, and / or to provide the functionality as required by one or more of the embodiments disclosed herein, in particular the embodiments of the first aspect, the second aspect and / or the third aspect.

[0044] It is noted that a reference to an aspect of the subject matter disclosed herein naturally also includes a reference to one or more embodiments of that aspect. For example, the statement that a program element controls a method according to the first aspect includes embodiments according to which the program element is configured to control a method according to one or more embodiments of the first aspect. Therefore, in general, the statement that a method according to the first aspect is referenced includes embodiments according to which the referenced method is implemented according to one or more embodiments of the first aspect (and / or the second aspect and / or the third aspect).

[0045] Unless otherwise specified, numerical values ​​are to be understood as including a ±5% window; i.e., for example, a threshold value of 0.09, according to one embodiment, includes a threshold value within the interval of (0.09 ± 5% of 0.09) = [0.0855; 0.0945], and a percentage value of 9%, according to another embodiment, includes a percentage value within the interval of 9% ± 5% of 9% = [8.55%; 9.45%]. According to a further embodiment, numerical values ​​and / or percentage values ​​are to be understood as including a ±10% window.

[0046] According to one embodiment, a method disclosed herein can define the functionality of a device disclosed herein without being limited to the device-specific features. In this respect, each functionality of a device disclosed herein is intended to implicitly disclose a corresponding method that is defined exclusively by the disclosed functionality. Conversely, according to one embodiment, a method disclosed herein can be carried out with any suitable known device (which may have a single element or several interacting elements). In this respect, each method disclosed herein is intended to implicitly disclose a corresponding device configured to carry out the method.

[0047] A general reference to embodiments (for example, of a method), for example by the wording "according to at least one embodiment", by the wording "according to one or more embodiments" or the wording "according to embodiments" also includes in particular the combination of features of a corresponding independent claim without further restrictions (for example, the method according to claim 1).

[0048] Unless explicitly stated otherwise, a list of features or process steps according to one embodiment does not define a sequence of the features or process steps in the order of the list. According to another embodiment, a list of features or process steps defines a sequence of the features or process steps as specified in the list.

[0049] In some embodiments mentioned above, the first occurrence of a feature was referred to as the feature with the indefinite article, for example, both when describing embodiments of the first aspect and when describing embodiments of the second aspect. However, it should be understood that the use of the indefinite article or the definite article in this disclosure is not restrictive, and that a feature referred to in different embodiments, regardless of whether it is designated with the definite article or the indefinite article, refers to the same feature in at least one embodiment. Therefore, in a combination of different embodiments, the feature can be referred to with the indefinite article at its first occurrence and with the definite article at subsequent occurrences.Furthermore, according to one embodiment, a feature referred to in the specific article can be designed without the embodiments described above. In addition, in one embodiment, the first aspect and the second aspect are two different aspects of the same underlying idea.

[0050] It should be noted that, unless explicitly stated otherwise, numerical terms (first, second, third, etc.) serve only to identify different elements (for example, a signal), without implying a sequence of procedural steps or requiring or implying the existence of any of the other different elements. For example, a reference to a second signal alone does not require that a first signal be generated before the second signal. Furthermore, a reference to a second signal in itself does not require that a first signal already exists or is even intended.

[0051] Further advantages and features of the present disclosure will become apparent from the following exemplary description of currently preferred embodiments, to which, however, the claimed subject matter is not limited. The individual figures in the drawings of this document are to be regarded merely as schematic and not to scale. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 shows a block diagram of an algorithm of a method according to embodiments of the items disclosed herein. Fig. 2 to Fig. Figure 6 shows a time course of signals and values ​​related to Fig. 1 described, according to embodiments of the items disclosed herein. Fig. Figure 7 shows an inverter according to embodiments of the items disclosed herein. DETAILED DESCRIPTION

[0052] It is noted that similar or identical elements or components in different figures are identified by the same reference numbers, or by reference numbers that differ only in the leading digit or an appended letter. Such features or components, which are identical or at least functionally equivalent to the corresponding features or components in another figure, are described in detail in the following text only upon their first occurrence, and the description is not repeated for subsequent occurrences of these features and components (or the corresponding reference numbers). If an element appears multiple times in a drawing, in some cases not all elements are identified by reference numbers to improve clarity. Naturally, the corresponding description also applies to the elements not identified by a reference number.

[0053] It is understood that an exemplary implementation of the elements described below and referenced in the relevant drawings is shown and configured according to the specified description of the drawings, unless otherwise stated.

[0054] Fig. Figure 1 shows a block diagram 100 of an algorithm of a method according to embodiments of the items disclosed herein.

[0055] The block diagram 100 can, for example, be implemented in a control device of a converter. According to one embodiment, the method includes receiving a voltage request 102. According to one embodiment (in the case of a three-phase system), the voltage request 102 has three components 104, 204, 304, which are in Fig. 1 also with V U , V V and V Ware designated, where each component is the voltage requirement for the associated phase U, V, W of the three-phase system. According to one embodiment, the time course of each of the three components 104, 204, 304 of the voltage requirement 102 is sinusoidal. The three components 104, 204, 304 (V U , V V , V W ) are also referred to herein as the "voltage requirement of the relevant phase" U, V, W.

[0056] Furthermore, according to one embodiment, the method includes receiving a DC voltage 106 from a DC circuit, for example, a DC circuit from which the converter draws electrical energy to provide output power. The DC voltage 106 is in Fig. 1 also with V DC designated.

[0057] According to one embodiment, a modulation index 108, 208, 308 is calculated from each component 104, 204, 304 of the voltage requirement 102, which corresponds to the respective phase U, V, W in Fig. 1 also with M U , M V , and M W are designated. According to one embodiment, the modulation index M U , M V , M W defined for each of the three phases as the quotient of the voltage requirement 104, 204, 304 for the respective phase U, V, W divided by the DC voltage 106 of the DC circuit: MU=VU / VDC MV=VV / VDC MW=VW / VDC

[0058] The modulation indices are therefore each a quantity derived from the voltage requirement 102.

[0059] According to one embodiment, the calculation of the modulation index 108, 208, 308 takes place in a modulation index calculation block 110.

[0060] According to one embodiment, a minimum value of 112 and a maximum value of 114 are determined from all three modulation indices 108, 208, 308.

[0061] According to one embodiment, the minimum value is 112, which is in Fig. 1 also with M min is defined as Mmin=0−min(MU,MV,MW), where the function min (M U , M V , M W ) as a function value, yields the minimum among the three modulation indices.

[0062] Since one of the three components of the voltage requirement 102 is always negative in one embodiment, Mmin is overall positive in this embodiment and, in one embodiment, denotes the distance between the minimum possible voltage requirement (0% of V). DC) and the minimum modulation index among the three modulation indices 108, 208, 308 of the three phases U, V, W. In one embodiment, the time course of the minimum value 112 is mirrored across an axis parallel to the time axis in the relevant phase that yields the minimum among the three modulation indices, relative to the time course of the voltage request 102. In another embodiment, the minimum value 112 is provided by a calculation block 113, for example as shown in Fig. 1 shown.

[0063] According to another embodiment, the maximum value is 114, which is in Fig. 1 also with M max is defined as Mmax=1−max(MU,MV,MW), where the function max (M U , M V , M W ) as a function value, yields the maximum among the three modulation indices.

[0064] Since one of the three components of the voltage requirement 102 is always positive and less than or equal to one (100% of V) DC ) is, the maximum value is 114 M max also always positive and, in one embodiment, denotes the difference between the maximum possible voltage requirement (100% of V). DC ) and the maximum modulation index among the modulation indices 108, 208, 308 of the three phases U, V, W. In one embodiment, the time course of the maximum value 114 is mirrored across an axis parallel to the time axis in the relevant phase that yields the maximum among the three modulation indices, relative to the time course of the voltage demand 102. In another embodiment, the maximum value 114 is provided by a calculation block 115, for example as shown in Fig. 1 shown.

[0065] Since within a period of phase U, V, W, the other two phases also exhibit a maximum peak value, a maximum peak value occurs three times among the three phases within a period. Consequently, the frequency of the time course of the maximum value M is max 114 is three times higher than the frequency of the time course of each of the components 104, 204, 304 of the voltage requirement 102. Similarly, the frequency of the time course of the minimum value M is also min 112 three times as high as the frequency of the time course of each of the components 104, 204, 304 of the voltage requirement 102.

[0066] According to one embodiment, the minimum value M min 112 hereinafter also referred to as the first signal and the maximum value M max 114 is also referred to here as the second signal.

[0067] According to one embodiment, the minimum value 112 or the maximum value 114 is selected as the signal 121, depending on the minimum value, the maximum value, and a threshold. For example, the minimum value 112 or the maximum value 114 is selected as the signal, depending on a threshold and a difference 116 between the minimum value 112 and the maximum value 114. According to one embodiment, the difference 116 is formed by a subtractor (difference generator or subtraction block) 117 and is displayed in Fig. 1 also with M diff designated. According to one embodiment, the minimum value 112 and the maximum value 114 are input variables of the subtractor 117. According to one embodiment, the subtractor 117 is configured to subtract the minimum value 112 from the maximum value 114, for example as in Fig. Figure 1 illustrates this. According to one embodiment, the minimum value 112 is selected (and thus forms the selected signal) if the difference 116 is greater than or equal to the threshold. According to another embodiment, the maximum value 114 is selected (and thus forms the selected signal) if the difference 116 is less than the threshold. In other words, according to one embodiment, the minimum value 112 is selected if the answer to question 118, whether the difference 116 is less than the threshold, is no, as indicated at Figure 120. Fig. 1, and the maximum value 114 is selected if the question 118, whether the difference 116 is smaller than the threshold, is answered with yes, as specified at 122 in Fig. 1. According to one embodiment, depending on the answer to question 118, either the minimum value 112 or the maximum value 114 is injected into the modulation index 108, 208, 308 of each of the phases. According to one embodiment, this selective injection of the selected signal (i.e., in one embodiment, the minimum value 112 or the maximum value 114) into the modulation index 108, 208, 308 is achieved by adding the selected signal 121 to the modulation index 108, 208, 308 in each of the three phases U, V, W.

[0068] According to one embodiment, the minimum value 112 is selected by closing a switch 126, which couples an output of the calculation block 113 to an adder (summing generator) 128. This adder adds the selected signal 121 (here the minimum value 112) to each of the modulation indices 108, 208, 308 of the individual phases U, V, W, in order to provide a component 130, 230, 330 of a control signal 132 for pulse width modulation for each phase U, V, W. The components 130, 230, 330 of the control signal 132 are in Fig. 1 also with M Uinj , M Vinj and M Winj designated and the injection signal 121 also with M inj ).

[0069] According to one embodiment, the selection of the maximum value 114 is carried out by closing a switch 134, which couples an output of the calculation block 115 to an adder (for example, the adder 128), which adds the selected signal 121, i.e., the injection signal (here the minimum value 114), to each of the modulation indices 108, 208, 308 of the individual phases U, V, W, in order to provide for each phase U, V, W a component 130, 230, 330 of a control signal 132 for pulse width modulation.

[0070] According to one embodiment, question 118, whether the difference 116 is less than the threshold, is implemented in a decision block 119. For example, in one embodiment, the decision block 119 provides a switching signal 136 to switch 126 to activate switch 126 and thereby inject the minimum value 112 into modulation indices 108, 208, and 308 if the difference 116 is greater than or equal to the threshold. In another embodiment, the decision block 119 provides a switching signal 138 to switch 134 to activate switch 134 and thereby inject the maximum value 114 into modulation indices 108, 208, and 308 if the difference 116 is less than the threshold.

[0071] As explained, block diagram 100 can, for example, be implemented in a control device of a converter. According to one embodiment, parts of block diagram 100, for example individual blocks 110, 113, 115, 117, 119, 128, can be implemented in software or in hardware.

[0072] Fig. 2 to Fig. Figure 6 shows a time course of signals and values ​​related to Fig. 1 described, according to embodiments of the items disclosed herein.

[0073] This shows Fig. 2 the modulation indices 108, 208, 308 over time t, each for a complete period with a period duration of 141.

[0074] Fig. Figure 3 shows the first signal 112 (minimum value M). min ) and the second signal 114 (maximum value M) max ) over time t.

[0075] Fig. 4 shows the difference value 116 (M diff) over time t together with a threshold value 140 according to embodiments of the items disclosed herein, wherein the threshold value 140 has the value 0.09, for example as in Fig. Figure 4 shows that, according to embodiments of the items disclosed herein, intersection points 142, 143, 145, 147 between the time course of the difference value 116 and the threshold value 140 define the times at which a change between the first signal 112 and the second signal 114 occurs, symbolized by the dashed lines 144 between Fig. 3 and Fig. 6.

[0076] Fig. 5 shows the injection signal 121 (M inj ) over time t. As can be seen from the synthesis of the Fig. 3 to Fig. As can be seen in Figure 5, the first signal 112 is selected during a first part 146 of the period 141, while the second signal 114 is selected during a second part 148 of the period 141. According to one embodiment, the injection signal 121 is a periodic signal. According to another embodiment, a period 150 of the injection signal 121 comprises two first parts 146, 246 and two second parts 148, 248, for example, in Fig. Figure 5 shows. According to one embodiment, the period 150 of the injection signal 121 is one third of the period 141 of the modulation index 108, 208, 308 (or of the components 104, 204, 304 of the voltage request 102, see Figure 5). Fig. 1) In other words, the injection signal 121 is a third harmonic of the modulation indices 108, 208, 308 or the voltage request 102.

[0077] Fig. Figure 6 shows the components 130, 230, 330 of the control signal 132 for a pulse width modulation (also referred to as a pulse width modulation signal) according to embodiments of the items disclosed herein over time t. According to one embodiment, the components 130, 230, 330 are formed by adding the injection signal 121 to each of the modulation indices 108, 208, 308, for example as by the Fig. 2 to Fig. 6 illustrates.

[0078] As below with reference to Fig. As explained in more detail in section 7, an inverter according to embodiments has switches with which a phase U, V, W of the inverter can be switched to a high voltage level (for example, V DCThe DC voltage of the DC circuit can be switched to a high level or to a low level (e.g., 0) of the DC voltage of the DC circuit. During a period of 150, the states of the switches in the inverter change; however, for any given phase, only the switch connected to the high level (high-level switch, high-side switch) or the switch connected to the low level (low-level switch, low-side switch) can be conducting (i.e., "on"), but not both, as this would cause a short circuit in the DC circuit. Since the switches are real switches and the switching times are not zero, one embodiment requires ensuring a time interval between the conducting state of the high-level switch and the conducting state of the low-level switch, particularly to avoid unwanted interference (also known as "cross-conduction").According to one embodiment, this is ensured by the first parts 146, 246 of the period 150. For example, according to one embodiment, the components 130, 230 are at least temporarily zero during the first part 146 of the period 150, for example as in . Fig. 6 shown.

[0079] According to one embodiment, current measurement is performed in one phase while the switch connected to the high level is open and the switch connected to the low level is closed. This is also referred to in one embodiment as "low-side" current measurement, i.e., the current-sensing device (for example, a current-sensing resistor, in particular a shunt resistor) is connected between a switch and the low voltage level.

[0080] According to one embodiment, a current measurement in a phase U, V, W can only be performed if the relevant component of the control signal 132 is less than 1, i.e., if the duty cycle of the pulse width modulation in that phase is less than 100%. In one embodiment, a current measurement for a component is possible if the component of the pulse width modulation signal 132 has a value of 0.95 (duty cycle 95%) or lower. In other words, no current measurement can be performed in a phase in which a component of the control signal 132 is one (i.e., 100%), for example, for component 330 during the second parts 148, 248 of the period duration in the first period of the injection signal 121, which is in Fig. 5 is denoted by 150. However, during the second part of the period, which is in Fig. Since terminals 5 are labeled 148 and 248, current measurement is possible.

[0081] In one embodiment, the sum of the currents I U , I V , I W in the 3 phases U, V, W zero, ie IU+IV+IW=0

[0082] Consequently, in this embodiment, where currents flow exclusively in the three phases, current measurement in two phases is sufficient, since the current in the third phase can be calculated from the other two phases.

[0083] Due to the phase shift of the three phases U, V, W of 120 degrees, the peak value of the modulation index is 108, 208, 308 according to one embodiment. 1 / 3=0.57735 as in Fig. 2 shown.

[0084] Fig. Figure 7 shows an inverter 160 according to embodiments of the items disclosed herein.

[0085] According to one embodiment, the inverter 160 has an input which is connected (or can be connected) to a DC circuit 162 and a three-phase output 164, for example as in Fig. Figure 7 shows the inverter. According to one embodiment, the inverter has a current regulator 166 and a control device 168, which receives a voltage request 102 from the current regulator 166. According to one embodiment, the control device 168 is configured to control the voltage request 102 with reference to the current regulator 166. Fig. 1. To carry out the method described. For this purpose, the control device 168, according to one embodiment, comprises a processor device 170 and a storage device 172 in which a program element of a computer program product is stored. According to one embodiment, the program element is configured to control, when executed on the processor device 170, a method according to the first aspect, for example, a method as described with reference to Fig. 1 is described. According to a further embodiment, the inverter has a pulse width modulator block 174 for controlling switches 176, 178 of the inverter 160 according to the control signal 132, which the control device 168 generates, and thereby generating a three-phase output at the output 164. According to one embodiment, each phase U, V, W of the three-phase output 164 can be connected via a switch 176 to a high level 180 of the DC voltage circuit 162 and via a switch 178 to a low level 182 of the DC voltage circuit 162. For low-level current measurement, a current measuring device is arranged between the switches 178 and the low level 182, in Fig. 7 schematically and generally indicated at 184.

[0086] It should be noted that, for example, an algorithm block diagram, a procedure, and a control device such as those described herein are not limited to the specific entities described in some embodiments. Rather, the items disclosed herein can be implemented in numerous ways while still providing the disclosed specific functionality.

[0087] According to embodiments of the items disclosed herein, any suitable entity (e.g., a block, a component, a unit, a device, an element, a switch, etc.) can be provided, at least partially, in the form of corresponding computer programs that enable a processor device to provide the functionality of the corresponding entity as described herein. According to other embodiments, any suitable entity as described herein can be provided in hardware. According to other hybrid embodiments, some entities can be provided in software while other entities are provided in hardware.

[0088] It should be noted that each entity disclosed herein is not limited to a single, dedicated entity as described in some embodiments. Furthermore, the items described herein may be provided in various ways with varying degrees of granularity at the device level or at the software module level, while still providing the specified functionality. It should also be noted that, according to some embodiments, a separate entity (e.g., a software module, a hardware module, or a hybrid module) may be provided for each of the functions disclosed herein. According to other embodiments, one entity (e.g., a software module, a hardware module, or a hybrid module) may be configured to provide two or more functions as described herein. According to yet other embodiments, two or more entities (e.g., blocks, components, units and devices, elements, switches, etc.) may be configured to provide two or more functions as described herein.) be configured to provide a function as described herein. For example, the literal disclosure of a switch provides an embodiment comprising a single switch, as described in the literal disclosure. Furthermore, the literal disclosure of a switch also provides an embodiment comprising two or more (for example, parallel-connected) switches that act as one switch.

[0089] According to one embodiment, the control device includes a processor device which has at least one processor for executing at least one program element, which may correspond to a corresponding software module.

[0090] It should be noted that the implementations described herein, in particular those illustrated in the drawings, represent only a limited selection of possible combinations of embodiments of the present disclosure. It is generally possible to combine the features of different embodiments in a suitable manner, so that, for a person skilled in the art, a multitude of combinations of different embodiments are to be considered disclosed with the embodiments explicitly disclosed herein. Furthermore, it should be mentioned that terms such as "a" or "one" do not exclude a plurality. Terms such as "containing" or "having" do not exclude further features or process steps. Consequently, according to one embodiment, the term "having" or "containing" means "having, among other things." According to another embodiment, the term "having" or "having" means "consisting of."According to one embodiment, the term “set up for” includes, among other things, the meaning “configured to”.

[0091] According to one embodiment, the term "based on" is used herein to mean "using" and vice versa. For example, generating a control signal for pulse-width modulation based on the voltage request and the selected signal means generating the control signal using the voltage request and the selected signal. According to one embodiment, the term "based on" or the term "using" does not preclude further dependencies. For example, the feature that the selection is "dependent on the voltage request" does not preclude the selection being based on a threshold.

[0092] The term "in particular" here refers generally to optional features.

[0093] The expression "A and / or B" usually includes "only A," "only B," and also "A and B." In an expression referring to a list of features, "at least one" always includes the individual features as well as any combination of features. For example, the expression "at least one of the features A and B" includes the feature "only A," "only B," and "A and B." Similarly, the expression "at least one of the features A or B" includes the feature "only A," "only B," and "A and B." Similarly, the expression "at least one of the features A, B" includes the feature "only A," "only B," and "A and B."

[0094] It should also be noted that reference numerals in the claims should not be interpreted as limiting the scope of the claims. Furthermore, it should be noted that reference numerals in the description and the description's reference to the drawings should not be interpreted as limiting the scope of the description. Rather, the drawings merely illustrate an exemplary implementation. a specific combination of several embodiments of the items disclosed herein, wherein any other combination of embodiments is equally possible and is to be considered disclosed with this application. In summary, it should be noted:

[0095] A method is disclosed comprising: receiving a voltage request 102; generating a first signal 112; generating a second signal 114; selecting one of the first signal 112 and the second signal 114 as the selected signal 121; and generating a control signal 132 for pulse width modulation based on the voltage request 102 and the selected signal 121. A converter and a computer program product are also disclosed. Reference number list 100 block diagram 102 Voltage requirement 104 Component of 102 (Phase U) 106 DC voltage 108 Modulation Index (Phase U) 110 Modulation Index Calculation Block 112 minimum value (first signal) 113 Calculation block for 112 114 maximum value (second signal) 115 Calculation block for 114 116 Difference between 112 and 114 subtract 117 Question 118: Difference 116 < threshold? 119 Decision block 120 No 121 selected signal 122 Yes 126 switches 128 Adders 130 Component of 132 (Phase U) 132 Control signal for PWM 134 switches 136 Switching signal for 126 138 Switching signal for 134 140 threshold 141 Period of 102 142 Intersection point between 116 and 140 143 Intersection point between 116 and 140 144 changes between 112 and 114 145 Intersection point between 116 and 140 146 first part of the period 141 147 Intersection point between 116 and 140 148 second part of the period 141 150 Period duration of the injection signal 121 160 Inverter 162 DC circuit 164 three-phase output 166 Current regulators 168 Control device 170 processor device 172 Storage device 174 Pulse width modulator block 176 switches, connected to 180 178 switches, connected to 182 180 high level of 162 182 lower level of 162 184 Current measuring device 204 Component of 102 (Phase V) 208 Modulation Index (Phase V) 230 Component of 132 (Phase V) 246 first part of the period 141 248 second part of the period 141 304 Component of 102 (Phase W) 308 Modulation Index (Phase W) 330 Component of 132 (Phase W)

Claims

[1] Having a method: Receiving a voltage request (102); Generating a first signal (112); Generating a second signal (114); Selecting one of the first signal (112) and the second signal (114) as the selected signal (121); Generating a control signal (132) for pulse width modulation based on the voltage request (102) and the selected signal (121), wherein the selection of the first signal (112) or the second signal (114) is based on a difference between the first signal (112) and the second signal (114). [2] Method according to claim 1, wherein the voltage requirement (102) is periodic and defines a period duration (141); wherein the first signal (112) is selected during a first part of the period (141); and where the second signal (114) is selected during a second part of the period (141). [3] Method according to claim 1 or 2, further comprising at least one of the following features: the first signal (112) is generated based on the voltage request (102); the second signal (114) is generated based on the voltage request (102); the first signal (112) is a third harmonic of the voltage request (102); the second signal (114) is a third harmonic of the voltage request (102). [4] Method according to any one of claims 1 to 3, wherein the voltage requirement (102) comprises a component (104, 204, 304) for each phase of a multiphase system; wherein the control signal (132) comprises a component (130, 230, 330) for each phase of the multiphase system; and wherein the selected signal (121) is used for each phase of the multiphase system; in particular where the multiphase system is a three-phase system. [5] Method according to claim 4, wherein, based on the components (104, 204, 304) of the voltage requirement (102), a minimum value and a maximum value of a quantity (108, 208, 308) derived from the voltage requirement (102) is determined; and where the first signal (112) is the minimum value and the second signal (114) is the maximum value; in particular wherein the first signal (112) is selected as the selected signal (121) if the difference between the maximum value and the minimum value is greater than or equal to the threshold (140) and wherein the second signal (114) is selected as the selected signal (121) if the difference between the maximum value and the minimum value is less than the threshold (140). [6] Method according to any one of claims 1 to 5, wherein the control signal (132) controls a pulse width modulation in an inverter (160); wherein the inverter (160) takes energy from a DC circuit; where a modulation index is defined as the quotient of the voltage requirement (102) divided by a measured DC voltage of the DC circuit; in particular where the threshold is 0.

09. [7] Method according to any one of claims 1 to 6, wherein an intermediate signal (108, 208, 308) is generated from the voltage request (102) and the selected signal (121) is injected into the intermediate signal (108, 208, 308) to generate the control signal (132). [8] Converter comprising a control device (168), wherein the control device (168) is configured to receive a voltage request (102); wherein the control device (168) is configured to generate a first signal (112) and to generate a second signal (114); wherein the control device (168) is configured to select one of the first signal (112) and the second signal (114) as the selected signal (121) based on a difference between the first signal (112) and the second signal (114); and wherein the control device (168) is configured to generate a control signal (132) for pulse width modulation based on the voltage request (102) and the selected signal (121). [9] Converter according to claim 8, wherein the control device (168) has a current regulator which determines the voltage requirement (102); and / or wherein the converter is an inverter (160). [10] Computer program product comprising a program element which is configured to control a method according to any one of claims 1 to 7 when executed on a processor device (170).

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