Efficient Vorladeschaltungen für Hochspannungs-Kondensatoren – Automotive

An active, hysteresis behaftete Abwärtswandlerschaltung improves the Wirkungsgrad and verringert de Platzbedarf der Ladeschaltungen für Hochspannungs-Zwischenkreiskondensators in EVs. If all goes well, it’s just a matter of doing it for a while.

In the electrical power supply of electrical appliances (EVs) you will usually find a weak alternating current capacitor, which is why the current at the input of the traction converters is minimal. When you switch on an electric car, you should let it charge in an orderly manner. Free the man who is standing in front of the drive on the battery voltage, prevents the Entstehen von Lichtboog and the Anschlüssen der Schütze, which can drive with the Zeit zu Totalausfällen.

The conventional method for charging a Swiss travel capacitor is based on a power widening with the capacitor in a series of its circuits, soft an RC network is installed. If the following capacitors with a higher power are used and the battery voltages are carried out in a standard way, the installed exponential exponential exponential is achieved. If you get an uncomplicated way of working, you can put a passive active active Vorladeschaltung in the system.

Is it possible to be active?

If a passive power widening is used, an RC switch is realized, the capacitor is asymptotically displayed. If you do not pay attention, the active front load switch can be realized with a drawn Abwärtswandler, whereby a hysteresis behavior regulation becomes a constant charging current and the capacitor abgibt. This constant current ensures that the linear capacitor voltage (VCAP) is performed on the battery voltage (VBATT). Figure 2 and Comparison 1 describe these figures.

dV/dt = ICharge / CDC link (Gleichung 1)

First, the height of the inheritance order charges (ICHARGE) must be determined. There is a problem that comes from Gleichung 2, from the Gesamtladungsmenge (QDC_LINK) in the Swiss travel capacitor, distributed by the gewünschte Vorladezeit (tCHARGE).

ICHARGE = QDC LINK / tCHARGE (Gleichung 2)

QDC LINK is the product of the Kapazität des Zwischereiskondensators (CDC LINK) and the battery voltage VBATT (siehe Gleichung 3).

QDC LINK = CDC LINK x VBATT (Draw 3)

Description of the Berechnungs-Tools

Due to the floating ground potential of the active Vorladeschaltung of the Potenzial in the Schaltknoten-entspricht, the Versorgung of the Regelungssystems becomes an isolated Bias-Versorgung benötigt. Mithilfe a Rechen-Tools is not as simple as de Leistungsaufnahme of the Regelungsschaltung non de Fähigkeiten der isolierten Bias-Versorgung übersteigt, de Spannung sonst jijsammenbräche.

In a reference design designed by Texas Instruments, if it is one of the basic principles of a high-voltage preload switching trade, an active loss with the energy supply is created, the energy efficiency is broken and the effective Ladezeit acquisition. In the reference design, the fully isolated bias version of TPSI3052-Q1 is used by TI, the isolated secondary side with a capacity of 83 mW can be used. The large anteil and the power supply are at the Gate-Treiberstrom, the Reststromaufnahmen of the building element and the Widerstandsteiler. Gleichung 4 drückt voor de Gate-Ansteuerung ergorderliche Leistung (PGATE_DRIVE) als Produkt from dem Gate-Treiberstrom (IGATE_DRIVE) und der Gate-Treiberspannung (VS_GATE_DRIVER) aus, die sich in der Fallen von Referenzdesigns 15 V.

PGATE DRIVE = IGATE DRIVE x VS GATE DRIVER (Draw 4)

If the bias is 5, then the gate current of the product is from the total gate current (QG) of the MOSFETs and the switching frequency (FSW) is.

IGATE DRIVE = QG x FSW (Gleichung 5)

After the FSW had gone through the VCAP inflow phase 6 months ago, the FSW-to-VCAP characteristic in figure 3 was of the form that one of the following parables was. Whoever can perform the representation can reach the maximum gate current at the maximum frequency (FSW_MAX), which is set anyway, when the VCAP has half of the VBATT involvement. Continue 7 times with the FSW_MAX, VBATT, the Inductance (L) and the Peak-to-Peak-Spulenstrom (dI).

FSW = (VCAP – (V²CAP/VBATT)) / (L x dI) (Gleichung 6)

FSW MAX = VBATT / (4 x L x dI) (Gleichung 7)

Use of the Berechnungs-Tools

The tool asks for different input parameters for the input. If you know that they are not necessary inputs, you can give the optional inputs a gray background. The available options have ended up in the gray areas for the reference design, which can be done after the costs have been made. In the white cells there are signs that calculate results. While the rights of one of them are a mess, it is a fact that the pop-up of the following text can be changed. There is an error, a faulty configuration that does not contain clear markings. This can be an iterative process, while the information is released, which compensates the Maus with a number of simple steps.

Anforderungen und das Vorladesystem

The image shows the first summary of the operating system tools that enable the charging function (ICHARGE_REQUIRED) with the system parameters VBATT, tCHARGE and CDC_LINK.

Induction and charging programming

There are 5 images of the tool parts which show the continuous charging current (ICHARGE) at FSW_MAX. The duration of the current is in principle identical with ICHARGE, while ICHARGE becomes larger or larger in the previous Abschnitt bechneten Wert von ICHARGE_REQUIRED as the mussel, then the desired Charging time (tCHARGE) is finalized.

Beachtet became muss die in Gleichung 7 ausgedrückte Relatie zwischen L, dI and FSW_MAX. If the jewelry is proportional to FSW, the maximum frequency (FSW_LIMIT) may not be described. The weight-induction energy sollte angemessene Werte for the RMS-Strom (IRMS > ICHARGE), the Sättigungsstrom (ISAT > IL PEAK) and the spannung ergeben and here jewels are conveniently reserved aufweisen.

Strommessung und Komparator-Sollwerte

There are 6 images of the calculation tools available on the following Widerstands (RB), the upper Widerstands (RT) and the hysteresiswiderstands to achieve the hysteresis switch, so that in the past started with the limit for the maximum and the minimum stuff flow (IL_PEAK bzw.IL_VALLEY) end values ​​were. Inserted are the Value of the flow width wider stand (RSENSE) and of RB, the flexible side is and you are done next. If you want this to be wanted, the Versorgungsspannung of the Comparators (VS_COMPARATOR) is corrected.

Bias-Versorgung und Beschränkungen der Schaltfrequenz

There are 7 parts of the research tools available in the field of the available MOSFETs (PREMAINING_FOR_FET_DRIVE), without the total supply requirement (PTOTAL) in the installation with the broader standards of the hysteresis switch (PCOMP_RESISTORS), the Gate-Treiber-IC (PGATE_DRIVER_IC) and the Comparator-IC (PCOMPARATOR_IC) calculated and this is subtracted from the maximum available performance of the TPSI3052-Q1 (PMAX_ISOLATED_BIAS_SUPPLY). We should use the Total Gate Load of the MOSFETs (QG_TOTAL), the Rest Current Take-off of the Bau-elements (IS_GATE_DRIVER_IC and ISUPPLY_COMP_IC) so that the Supply Voltage of the Gate-Treiber-ICs (VS_GATE_DRIVER_IC) is performed. Use the tool FSW_LIMIT (in figure 3 as red line version).

The calculation tool offers the best quality and lower factors with the signal-signal display that allows the display in MOSFET and the unmonitored frequency diode. If it is good, the comparator single and output rail-to-rail characteristic is settled. If the MOSFET is used, it is not suitable for the correct RDS(on) and a suitable parasitic capacitance function. In any case, the display of the MOSFET and the frequency diode lie in the switchable limits. Finally, a comparator with lighter offset and hysteresis voltage – taken on the maximum and minimum voltages at the current measurement – must be selected. During the simulation of the switch with the last error, the correct functional verifications cannot be performed.

Use the desired loading profiles

The operation of an active, hysterical electric vehicle signage that splits and replaces the wiring from the charging area for high-voltage travel capacitors in EVs was how costs and thermal energy were reduced.

The previous article describes the correct placement of the building elements, one of the existing profile profiles that you can realize. By developing techniques and tools it is possible that the function of electric cars becomes so broad, that the offered investments in the automotive industry can be carried out with improved energy management systems.

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