Method for determining a power loss-value of an electronic power circuit during an electrical period of a modulated control signal, and computing unit

Abstract

The invention relates to a method (100) for determining a power-loss value of an electronic power circuit during an electrical period of a modulated control signal, the method comprising: determining a linear average switching-energy value (110) of the electronic power circuit on the basis of a modulated control signal with a linear modulation; determining a non-linear average switching-energy value (120) of the electronic power circuit on the basis of a modulated control signal with a non-linear modulation, in particular overmodulation; determining a scaling-factor value (130) on the basis of the linear average switching-energy value and the non-linear average switching-energy value; and determining the power-loss value (140) on the basis of the linear average switching-energy value and the scaling-factor value. The invention also relates to a computing unit which is designed and configured to carry out the method (100).

Description

[0001] Description

[0002] Method for determining a power loss value of an electronic power circuit during one electrical period of a modulated control signal and computing unit

[0003] The present invention relates to a method for determining the power loss value of an electronic power circuit during one electrical period of a modulated control signal. The invention also relates to a computing unit configured and set up to execute the method.

[0004] In the prior art, power electronics are used to control electric traction drives or for energy conversion, for example in electric drives, whereby the power electronics are controlled or commutated using modulation methods, for example based on space vector pulse-width modulation (SVPWM). Within the power electronics, power semiconductors such as MOSFETs (metal oxide field-effect transistors) or IGBTs (bipolar transistors with insulated gates) are used, which are commutated or switched on or off depending on the position of the space vector.

[0005] The commutation processes, or the switching on and off, can follow a predefined mathematical pattern, which is determined by a control algorithm and / or a modulation method, so that the operating state of the power semiconductors is switched between conducting and non-conducting operation. Furthermore, with increasing torque and / or speed at a load to be switched, an increasingly higher effective phase voltage must be set. For this purpose, the duty cycle of the power semiconductors is increased by a controller. The power semiconductors are thus driven in such a way as to provide the increasing torques and / or speeds, thereby varying the power losses of the power semiconductors.Therefore, for non-destructive operation of power electronics, it is necessary to determine the power losses of the power semiconductors and to control them taking these losses into account. In particular, average power losses over one electrical period of a drive signal to the power semiconductors and / or average loss models are used for this purpose. However, power losses determined in this way indicate that switching losses would occur in the power semiconductor switches at all times during the electrical period. Thus, these power losses are only relevant if all phases are continuously switched over one electrical period and, for example, no overmodulation occurs.

[0006] Consequently, the power losses determined using known methods deviate from the actual power losses of the power semiconductors, particularly at excessive duty cycles (duty cycle >= 1 or duty cycle <= 0). In particular, the determined power losses at excessive duty cycles may indicate a higher power loss than actually occurs in the power semiconductor.

[0007] The object of the present invention is therefore to provide a technology that is more advanced than the prior art. In particular, it aims to improve the accuracy of determining power loss at excessively high duty cycles.

[0008] This problem is solved by articles with the features according to the independent claims. Advantageous embodiments are the subject of the dependent claims.

[0009] A method for determining the power loss value of an electronic power circuit during one electrical period of a modulated control signal is disclosed. Furthermore, the method includes determining a linear average switching energy value of the electronic power circuit based on a modulated control signal with linear modulation.

[0010] Furthermore, the method includes determining a non-linear average switching energy value of the electronic power circuit based on a modulated control signal with non-linear modulation, in particular overmodulation.

[0011] Furthermore, the procedure includes determining a scaling factor value based on the linear mean switching energy value and the nonlinear mean switching energy value.

[0012] Furthermore, the procedure includes determining the switching energy value based on the linear mean switching energy value and the scaling factor value.

[0013] The electronic power circuit can, for example, comprise one or more power semiconductors. In particular, the power semiconductors can be designed as semiconductor switches. For example, the semiconductor switches can be designed as MOSFETs (metal oxide field-effect transistors) and / or IGBTs (bipolar insulated-gate transistors).

[0014] The power loss value can, for example, include the power loss from the switching energy of the electronic power circuit. Alternatively or additionally, the power loss value can include the power loss from the switching energy of a power semiconductor in the electronic power circuit.

[0015] The disclosed method can be used, for example, to control the electronic power circuit with a modulated control signal. Particularly preferably, the disclosed method can be used during overmodulation of the modulated control signal, such as occurs with space vector pulse-width modulation (SVPWM). The scaling factor value can, for example, adjust the power dissipation value such that the deviation between the specified power dissipation value and the actual power dissipation value of the electronic power circuit is minimized. Particularly preferably, the scaling factor value can adjust the power dissipation value during overmodulation when an increased duty cycle of the control signal occurs. In this adjustment, for example, a value of the power dissipation value can be increased or decreased.

[0016] This allows, for example, a higher accuracy in determining the power loss value compared to loss estimators that determine power losses based solely on an average value.

[0017] Furthermore, the power dissipation value can, for example, be configured to be used by a control device to control the electronic power circuit. The control device can also determine a control signal for the electronic power circuit based on the power dissipation value. In this respect, the electronic power circuit can preferably be controlled based on the power dissipation values, so that the electronic power circuit can be operated, for example, in such a way that it can deliver a higher power output without being damaged or destroyed.

[0018] Furthermore, the scaling factor value can be determined based on provided lookup table data, a modulation level of the modulated control signal and / or a phase shift of the modulated control signal.

[0019] For example, the scaling factor values ​​can be determined based on a comparison of lookup table data with a provided current value, a provided voltage value, and / or a provided temperature value from the electronic power circuit. Furthermore, the modulated control signal can be a space vector modulated (SVPWM) signal.

[0020] Furthermore, the linear average switching energy value can be determined based on the following formula:

[0021] - 1 !-sin( <p e j — cf») ,, x E o !

[0022] - - - d( <p el - *) = -■-

[0023]

[0024] where

[0025] Eswi is the linear average switching energy value;

[0026] Eo one of the switching energy supplied to the electronic power circuit;

[0027] Io a current supplied to the electronic power circuit; ! a peak current value of the supplied current;

[0028] CP ei an electrical angle of the electronic power circuit;

[0029] and

[0030] a phase shift of the electronic power circuit.

[0031] Furthermore, the non-linear average switching energy value can be determined based on the following formula:

[0032] E SW 2 = ± (j0^sin( <p e , - 4>) d(cp el - 4>) + sin( <p e , - 4>) d(cp el - 0>))

[0033]

[0034] where

[0035] Esw2 is the nonlinear average switching energy value;

[0036] Eo one of the switching energy supplied to the electronic power circuit;

[0037] Io a current supplied to the electronic power circuit; ! a peak current value of the supplied current;

[0038] CP ei an electrical angle of the electronic power circuit;

[0039] a phase shift in the electronic power circuit; and <p ;<p2ein Intervall des modulierten Steuersignals, in welchem ein Dutycycle > = 1 or <= 0 is, is.

[0040] Furthermore, the non-linear average switching energy value can be determined based on the following formula:

[0041] E o If , ,

[0042] sin c amped ( eJ - *) d( <p e , - *)

[0043] 2TT I O J

[0044]

[0045] oa>

[0046] where

[0047] Esw2 is the nonlinear average switching energy value;

[0048] Eo one of the switching energy supplied to the electronic power circuit;

[0049] Io a current supplied to the electronic power circuit; ! a peak current value of the supplied current;

[0050] CP ei an electrical angle of the electronic power circuit;

[0051] a phase shift in the electronic power circuit; and

[0052] ;<p2ein Intervall des modulierten Steuersignals, in welchem ein Dutycycle > = 1 or <= 0 is, is.

[0053] The function S m clamped can be particularly in the interval between «^and <p20 annehmen.

[0054] Furthermore, the scaling factor value can be determined based on the following formula:

[0055] ESW 2 sin clam P ed C <p el -^dC <p el -^ sin clam Ped (<p el -<P)d(<p el -<P) ^ sw l smGp ei -<&)d(cot-0) sin (l°el- dVd(Mt- <t>)

[0056] sin ctom P ed (y e; -0W e; -0)

[0057]

[0058] 2

[0059] where

[0060] SLRF is the scaling factor value. Furthermore, the procedure can also include providing the switching energy value.

[0061] Also disclosed is a computing unit that is designed and equipped to execute the disclosed procedure.

[0062] The present invention is described in detail below with reference to the figure. It shows:

[0063] Fig. 1 shows an exemplary sequence of a method for determining a power loss value of an electronic power circuit during one electrical period of a modulated control signal.

[0064] The present invention is described below with reference to a preferred embodiment and the figure. However, this description of the embodiment should not be considered exhaustive.

[0065] Fig. 1 shows a method 100 for determining a power loss value of an electronic power circuit during an electrical period of a modulated control signal.

[0066] Method 100 comprises determining a linear mean switching energy value 110 of the electronic power circuit based on a modulated control signal with linear modulation. Method 100 further comprises determining a nonlinear mean switching energy value 120 of the electronic power circuit based on a modulated control signal with nonlinear modulation. Overmodulation may be used in this process. Method 100 also comprises determining a scaling factor value 130 based on the linear mean switching energy value and the nonlinear mean switching energy value. Method 100 further comprises determining the power loss value 140 based on the linear mean switching energy value and the scaling factor value. The linear mean switching energy value is determined based on the following formula (1):

[0067] (i) s»! = d(Vel - i

[0068]

[0069] where

[0070] Eswi is the linear average switching energy value;

[0071] Eo one of the switching energy supplied to the electronic power circuit;

[0072] Io a current supplied to the electronic power circuit; ! a peak current value of the supplied current;

[0073] CP ei an electrical angle of the electronic power circuit;

[0074] and

[0075] a phase shift of the electronic power circuit.

[0076] Furthermore, either the non-linear mean switching energy value is determined based on the following formula (2) or the following formula (3):

[0077] (

[0078]

[0079] 2) £ S W2 = f; • 7- (Jo-0 sin ^ei " ) d ^ei ~ sin( <jp eI - 4>) d( <p el - 4>))

[0080] where

[0081] Esw2 is the nonlinear average switching energy value;

[0082] Eo one of the switching energy supplied to the electronic power circuit;

[0083] Io a current supplied to the electronic power circuit; ! a peak current value of the supplied current;

[0084] CP ei an electrical angle of the electronic power circuit;

[0085] a phase shift in the electronic power circuit; and

[0086] <p ;<p2ein Intervall des modulierten Steuersignals, in welchem ein Dutycycle > If the value is 1 or less than or equal to 0, then the value is zero. En I f ,

[0087] (3) E SW 2 = -^- - - sin c amped ( eJ - *) d( Ve , - *)

[0088] 2TT I O J

[0089]

[0090] oa>

[0091] where

[0092] Esw2 is the nonlinear average switching energy value;

[0093] Eo one of the switching energy supplied to the electronic power circuit;

[0094] Io a current supplied to the electronic power circuit; ! a peak current value of the supplied current;

[0095] CP ei an electrical angle of the electronic power circuit; <t>a phase shift in the electronic power circuit; and

[0096] <p ;<p2ein Intervall des modulierten Steuersignals, in welchem ein Dutycycle > = 1 or <= 0 is, is.

[0097] The function s in clamped takes up in particular the interval between «^and <p20 an.

[0098] Furthermore, the scaling factor value is determined based on the following fourth formula:

[0099] F — sin ciam P ed (ffl e ,-0)d(ffl e ,-0)

[0100] (F4) SLRF = ^ = 2nI °^ n m - =

[0101] sin ctom P ed (y e; -0)d(y e; -0) _ sin ctom P ed (y e; -0W e; -0)

[0102]

[0103] ■^oy sinGp ei -0)d(cot-0) 2

[0104] where

[0105] SLRF is the scaling factor value.

[0106] Furthermore, the scaling factor value can also be determined based on provided lookup table data, a modulation level of the modulated control signal, and / or a phase shift of the modulated control signal. The modulated control signal can also be a space vector modulated signal (SVPWM). Furthermore, the method can also include providing the power dissipation value.

[0107] Furthermore, a computing unit is disclosed which is designed and configured to execute the method described above. The computing unit can acquire the necessary measured values ​​from sensors and output a specific power loss value. The computing unit can be a dedicated computing unit or perform additional functions. Reference symbol

[0108] Methods for determining a power loss value; Determining a linear average switching energy value; Determining a nonlinear average switching energy value; Determining the power loss value< / t> < / t>

Claims

Claims 1. Method (100) for determining a power loss value of an electronic power circuit during one electrical period of a modulated control signal, comprising: Determining a linear mean switching energy value (110) of the electronic power circuit based on a modulated control signal with linear modulation; Determining a nonlinear mean switching energy value (120) of the electronic power circuit based on a modulated control signal with nonlinear modulation, in particular overmodulation; Determining a scaling factor value (130) based on the linear mean switching energy value and the nonlinear mean switching energy value; and Determining the power loss value (140) based on the linear mean switching energy value and the scaling factor value.

2. Method (100) according to claim 1, wherein The scaling factor value is further determined based on provided lookup table data, a modulation level of the modulated control signal and / or a phase shift of the modulated control signal.

3. Method (100) according to claim 1 or 2, wherein The modulated control signal has a space vector modulated signal (SVPWM).

4. Method (100) according to any one of claims 1 to 3, wherein The linear average switching energy value is determined based on the following formula: e» SW » 1 1 = -27T J J “0”-? <t>E“ u ■ l slll(y I Q "- t,) dc ^ <P. E , L - * 7 ) = n ■ 1 i0 where Eswi is the linear average switching energy value; Eo one of the switching energy supplied to the electronic power circuit; Io a current supplied to the electronic power circuit; ! a peak current value of the supplied current; CP ei an electrical angle of the electronic power circuit; and 4> a phase shift of the electronic power circuit.

5. Method (100) according to any one of claims 1 to 4, wherein The non-linear average switching energy value is determined based on the following formula: E SW 2 = ± (j0^sin( <p e , - 4>) d(cp el - 4>) + sin( <p e , - 4>) d(cp el - 0>)) where ESW2 is the non-linear average switching energy value; Eo one of the switching energy supplied to the electronic power circuit; Io a current supplied to the electronic power circuit; ! a peak current value of the supplied current; CP ei an electrical angle of the electronic power circuit; 4> a phase shift of the electronic power circuit; and <p ;<p2ein Intervall des modulierten Steuersignals, in welchem ein Dutycycle > = 1 or <= 0 is, is.

6. Method (100) according to any one of claims 1 to 5, wherein The non-linear average switching energy value is determined based on the following formula: E stv2 = ~r [ - *) < / (<?«, - *) 2TT I O J oa> where ESW2 is the non-linear average switching energy value; Eo one of the switching energy supplied to the electronic power circuit; Io a current supplied to the electronic power circuit; ! a peak current value of the supplied current; CP ei an electrical angle of the electronic power circuit; 4> a phase shift of the electronic power circuit; and <p ;<p2ein Intervall des modulierten Steuersignals, in welchem ein Dutycycle > = 1 or <= 0 is; where the function S m clamped in the interval between «^and <p20 annimmt.

7. Method (100) according to claim 6, wherein The scaling factor value is determined based on the following formula: SLRF = ^ = sin ctom P ed (y e; -0)d(y e; -0) = = Ssw l sinC <p el -^d^t-^ sin^ei-^dCcot-cP) sin ctom P ed (y e; -0W e; -0) 2 where SLRF is the scaling factor value.

8. Method (100) according to any one of claims 1 to 7, wherein the procedure (100) further includes the provision of the loss performance value.

9. Computing unit designed and configured to perform the method (100) according to any one of claims 1 to 8.< / t>

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