Hello, I need help choosing an IGBT gate driver IC and the application is focused on a 3-phase AC motor inverter setup. Consider it is a 5 pole pair motor and needs to run at 5000rpm. Then what should be my gate driver's Tsw to switch on the IGBTs?
Considering the mentioned IGBT for the application: https://www.mouser.in/ProductDetail/onsemi-Fairchild/FGY120T65SPD-F085?qs=0lQeLiL1qya9zz3DoHiZYA%3D%...
https://www.infineon.com/dgdl/Infineon-IR2x14SS-DataSheet-v01_01-EN.pdf?fileId=5546d46269e1c019016a4... - Reference for this image.
As we know the current supposed to be supplied to the IGBT should be
Current = Gate charge(Qg) / Tsw
I need to filter some gate driver ICs which should be able to supply the current, but I can proceed with it only if I know the Tsw and I have no idea how to calculate it for the application so that the motor runs at the desired RPM (mentioned above).
It'll be helpful if someone can share any formula or application notes which can guide me to find it.
Thank you in advance.
Solved! Go to Solution.
Gate Driver IC's
It is giving just 15V output out of flyback converter.
Since, we discussed so much variety of design, may I know was is the status of your design and is it really helping you to proceed in right direction.
Thank you for posting on Infineon community.
The formula shared by you are correct. However, if I understood correctly your main doubt is regarding selection of switching frequency or Tsw for your motor drive to calculate gate driver current.
Please provide below information to guide you.
1) There are many gate driver IC solutions available however, can you please confirm that you have selected a Fairchild IGBT and you need a Infineon gate driver IC for that.
2) Please provide information regrading your motor drive. Is your drive operating at high power or low power and will your switching frequency be fixed or variable.
General tips for motor drive applications.
Generally, the motor drives don't run at high switching frequency. One of the main limitation for switching frequency is the losses in the IGBT module of the inverter.
Prima facie , to choose a suitable switching frequency, I recommend you to check your IGBT based inverter module maximum switching loss permissible in such a way that the sum of conduction and switching loss does tend to exceed your device junction temperature at maximum operating ambient temperature.
By this way you will get a idea of what switching frequency (Tsw) you could have from application point of view and later when you provide the information asked, we can work out what will be your maximum switching frequency to calculate the driver current.
Hello, thanks for the quick reply
1. We have also considered this Infineon IGBT- INFN-S-A0007019043-1.pdf (widen.net) you could use this as well to find an appropriate gate driver, we are looking for a generalized approach or guideline to decide a gate driver.
2. We are designing a high power motor drive (12kW continuous and 25kw Peak), looking to operate with a peak rpm of 6500RPM. Also, our switching frequency is fixed, up to 20kHz.
Application notes and calculations along with any sample gate driver usable ( Half-bridge or 3Phase) would be great.
I understood your query. I would like to suggest you few steps to choose a correct gate driver specifically for motor drivers. The method may be iterative or one go procedure to select a gate driver.
1) First select IGBT as per your application rating (voltage , current and define the maximum operating ambient temperature ) requirements.
2) To decide the maximum switching frequency for the system , the data sheet of IGBT will give you the maximum limit i.e. you cannot choose your switching frequency more than data sheet value.
3) Now, you have to calculate the switching losses of the IGBT (for Infineon products use IPOSIM platform) at maximum ambient temperature. Vary the switching frequency in such a way that total losses(conduction +switching losses) does not exceed the junction temperature. By this way you will get another limitation on switching frequency.
4) Select a suitable motor controller and control bandwidth for the controller as per the motor harmonic balance (at higher switching frequency the harmonic frequency component will be less ). This will give a fair idea about the minimum switching frequency limitation.
5) The switching frequency selection also depends upon the dead time chosen between high and low side device.
Considering the above parameters, you can select a suitable maximum switching frequency and then you can go ahead with you gate driver calculations.
As per your request, I have attached the links which contains calculation notes specifically for motor drives.
The above application helps you to decide the dead time.
This will help you to select a gate driver.
This is a half bridge configuration driver IC which will help you to calculate the thermal and loss aspects of IC (its given at the end of note).
This will help you to design the gate driver and its circuit.
I hope the information will give you a detail procedure to select and design a gated river for motor applications.
Hello, sorry for the delay. Do you have any High-Power, Three-Phase Inverter or any Half-Bridge configuration based reference designs using any of Infineon's Half-Bridge Drivers such as EiceDRIVER™ 2EDi Product Family Dual-channel isolated 2EDSx reinforced, 2EDFx functional isolated 4 ... or the High-Side drivers 1ED3124MU12H - Infineon Technologies
Sorry to say but we do not have design document for your specific inverter design using the gate driver IC. However, I have given you the design procedure guidelines and if I request you to start your design and if you need any help we will always support you. Considering your problem, I am attaching few links where you can get some idea about the inverter design.
Again, I request you to start your design and if you need any help we will support you.
I hope you understood.
For your reference design, please refer to the evaluation board link attached. It will give you all the information what you want.
Hello, thanks a lot for the reference design and other Application notes. They were really helpful. I have the following queries:
1-A: The peak output power dissipation of the Gate Driver is not available in the datasheet, EiceDRIVER™ 2EDi Product Family Dual-channel isolated 2EDSx reinforced, 2EDFx functional isolated 4 ..., and I would be needing this value to size my Gate Resistor (Apart from experimental verification). Is this something I can calculate with Datasheet Parameters or is this term called something else?
1-B: Can I take my High-level output on resistance and Low-Levels' as well as 0 if no such value is mentioned in the Datasheet?
2. Do you have any Application Notes and/or Reference Designs/Guidelines for the following topics?
2-A: Capacitor Bank Sizing or Selection for a three-phase Inverter, and Filter Capacitors on the Input and Output side.
2-B: In the case of a gate driver having the ability to discharge the IGBT to a Negative Voltage ( to avoid Spurious Turn-on), Does the Driver create its own negative supply or Do I have to supply the driver with two different supplies?
2-C: Brake Resistor and Braking Terminals:
2-D: EMI/EMC Filters/Circuitry
3. I had also noticed the Gate Drivers in the Reference Design do not have any fault reporting capability. Is there any additional external protection circuitry added for the same which are then reported to the MCU?
Thanks a lot for the technical support. Regards
Thank you for your detailed queries and I would like to answer few of them now.
1) Since, direct value of peak power dissipation of IC is not given, you can still calculate it from data sheet parameter. In the data sheet attached by you, if you see the internal output resistance during ON (source) and OFF (sink) are given for different current rating.
Lets say you did not connect any external gate resistance. Then, the peak current of the device will flow through the internal output resistance and that will be treated as output peak power dissipation. Taking into mind that value, you can size your gate resistor which still can change based upon the ringing allowed on gate voltage and your desired dv/dt and di/dt.
I have attached the screen shot of peak parameters given in data sheet and also i have attached a link where you can find detailed procedure to design your gate resistor based peak power dissipation, ringing and speed.
2) Yes if the high and low level resistance values are not given in data sheet means they are negligible.
3)Yes you have to give separate different power supply(both positive and negative) to turn ON and turn OFF(to avoid spurious ON) the device.
4)Even though we don't support brake resistor but still i can help you with that. But I don't know what is brake terminals. Please tell me what kind of brake resistor is it and for what purpose.
5) EMI filter circuitry for what application ?
6 ) Capacitor sizing will tell you in some time.
Hello, thanks for the answers. I have the following follow-up questions for the answers.
1. As per your suggestion, do I just consider the peak power dissipation as i^2*R? And what about if these resistance values aren't given in the datasheet and I take them as 0, then how do I compute the peak power dissipation?
2. In regards to the brake terminals, instead of regenerative braking, if I would like to build a brake chopper circuitry (with a transistor and large resistor), could you suggest application notes and design guides for that?
3. EMI filtering for the PWM signals as well as any other areas to be implemented. Similar to what is used in the inverter reference design given by you.
Looking forward to the DC-Link Capacitor Bank sizing and output filter capacitor sizing. Thanks for the support!
1) I understood your doubt and its valid. There are many ways to design the gate resistor value. If the internal resistor value is zero ,then you can use a different method to select gate resistor, which is related to overshoot and oscillation in gate voltage.
The design method is as follows-
Due to parasitic present in gate circuit loop, the oscillations in gate voltage may occur because of resonance circuit formed(R,L,C) . Fortunately, with high Q factor value, the oscillations between C(input cap. of device) and L(path or loop inductance) can be controlled with a resistor.
PFA of resonance circuit formed.
Where, Rg= total gate resistor (internal to external resistor, if internal not given you can consider only external for your primary calculation), Ciss= device input cap. ( Cgd+Cgs).
If you keep very low value of resistor, the oscillation in gate voltage may overshoot and also result in faster turn on and high gate resistor will overdamp the oscillation and switching frequency will be effected. Generally, for design Q- factor is taken between 0.5 and 1.A q-factor greater than 0.5( critically damped) will give you faster turn ON and turn OFF. Initially, start with zero gate resistor and observe the oscillation and at which frequency its happening. Note that frequency and from device data sheet you will get C value and you can calculate your L by formula
Then after this you can use Q- factor formula to calculate your resistor value which is a iterative process to get your optimized gate resistor.
Where, w= oscillation frequency.
This is a general process to calculate the gate resistor value and is well practiced. If the gate internal resistor value is given, then to get the external resistor value you subtract the obtained value with internal one and if internal resistor value is zero, you can consider the obtained value as gate resistor value.
I hope this will help you to design the resistor value.
2)Regarding brake resistor, first you have to finalize the amount of brake energy you want to dissipate. If you want to dissipate the full energy in one pulse, then brake resistor needed of big size and if you dissipate it in few pulses, the the resistor size will be smaller. For this thermal simulation of brake resistor is needed which we don't support (talk to appropriate vendor he will help you). Once these requirement are finalized , I can help you to find a suitable Infineon device for the brake switching(one pulse or multiple pulse discharge).
3) Thank you for your explanation. The EMI filter design particular for inverter PWM signals vary a lot as per the system design as well. However, I have attached a link which will give you a fair idea for EMI particular to motor inverter applications.
4) For dc capacitor sizing for inverter applications, following is the method-
First, decide your rating and calculate your worst case current ripple across the inductor. By using the formula,
Where, dt= switching time duration in ripple is maximum (it depends upon the PWM technique eg- unipolar or bipolar).
Once you get the worst case ripple current value(di) you apply below formula to calculate the charge.
After this , fix your voltage ripple requirement across dc- bus and apply the below formula to get cap. value.
where, dq is the charge (which you will get from current ripple) and dV is the percentage ripple of dc bus voltage.
I hope the information shared will be helpful for your design.
Please let me know if you need any assistance while selecting Infineon components for your system.
Hello, thanks for your detailed and timely responses! I have the following questions about the following Gate Drivers:
1. Could you please reiterate the peak power dissipation calculations of the gate driver EiceDRIVER™ 1ED31xxMU12H Compact (infineon.com) and the calculation again?
2. In regards to dead-time values present in the datasheet, in the datasheet given above, one of the devices in the family had a programmable deadtime. However, the gate-driver considered in the reference design EiceDRIVER™ 1ED31xxMU12H Compact (infineon.com) does not have any information in regards to the dead-time of the device. What can be considered of this?
3. Can I use 2 High-Side Drivers in a half-bridge configuration? Instead of using a high-side and a low-side drivers.
4. If possible, could you recommend (either Half-Bridge or Single) Gate drivers, which have the features of Active Miller Clamps, Short Circuit Protection, UVLO, Peak Source and Sink Capabilities of at least 6A each, Capability of Bi-polar Supplies and Fault Pin capabilities.
Would like to ask queries about Capacitor Bank and Braking Resistors too soon, as always, thanks for the support!
1) For the similar gate driver IC we have done some power calculation which I am attaching for your reference.
For the GD IC shared by you, already output power dissipation is given which you can use directly.
2) The GD IC shared by you is a single channel IC which means single IC is designed to use for single device. For one half leg, you need to use two separate GD IC. Generally dead time is provision is given in those IC which have to drive both top and bottom device with a single IC. So, in such cases you can give dead time between top and bottom PWM (in such a way that top and bottom device do not turn on simultaneously) by using the PWM pulse release code in your microcontroller.
There are many other ways to provide dead time like you can use a additional FPGA or controller (in case you cant give dead time from the microcontroller code) which is used just to delay the input pulses of any of the switch in one leg.
3) Yes you can use two high side GD IC both for top and bottom device.
4) I recommend you to go with this IC for such high power motor applications due to following reasons.
a) High power motor applications where you might have to go with isolated GD IC.
b) High source and sink current requirements.
Hello, by this IC Do you mean the one I shared? Also, are there any single channel Gate Driver ICs which have any fault reporting capability?
1. We are looking for Overcurrent and Overvoltage protection as well from the input side ( DC Supply), could you recommend any ICs for the same? Voltage rating of >270v and Current rating of >100A
Yes I mean the IC which you have shared.
For over short circuit protection (de sat feature), I have attached the data sheet of the isolated GD IC. For over voltage protection, we don't have IC.
This IC will meet your gate driver strength capability as well can be used for high voltage applications.
Hello, thanks for the Gate Driver IC suggestion. I have the following doubts about the same.
1. When a datasheet says separate source and sink capabilities as 14A each, is it the same as a datasheet saying device's ratings are 14A/-14A peak output currents?
My IGBT needs about 4A for charging (Sourcing) and 6.4A (Sinking) for the discharging of its internal capacitances for the devices' turn on and turn off. Could you please mark which of the following Gate Drivers would be most appropriate?
- 1ED3123MU12H EiceDRIVER™ 1ED31xxMU12H Compact (infineon.com)
- 1ED3890MC12M EiceDRIVER™ 1ED38x0Mc12M Enhanced (infineon.com)
Could you also elaborate on UVLO threshold and picking devices with FLT Codes?
Thanks and Regards
1) Yes you are correct about source and sink current information.
2) For your IGBT, any one of the bottom two links provided by you is fine as per your gate current requirement. You can select them based upon other feature requirements as well. However, if you feel that your gate current may go much higher than what you estimated then you can straight away select the second bottom GD link.
For ULVO, please refer to attached image.
I did not understand what is picking devices with FLT codes.
BY FLT codes, I mean a gate driver IC capable of giving fault codes.
What would be a better choice , from an operational point of view? An option to provide negative voltage to my gate driver or picking a gate driver with an active miller clamp
Yes the IC are capable of giving fault signal. Generally in case of fault it will give a high signal to microcontroller using a fault signal.
Both are ok however, I would recommend you to go with negative voltage.
Hey there! Thanks for the detailed and timely technical support. We have done our design to a good extent, and have some queries in regards to the reference design given earlier:
There is a brake terminal in the final product here. Could you elaborate on the following?
1. What the recommended Braking resistor is for this reference design
2. What are the calculations used for the same to obtain this resistor value and its power dissipations?
Please find the answers of your questions below.
1) The resistor can be of any type which are used for braking. Generally, for high energy braking, helical coil type or grid type resistor are used because they have faster cooling. However, still I recommend you to go to website of any brake resistor manufacturer and tell them your energy dissipation requirement, resistor value and size constraint. They will guide you accordingly.
2) The calculation for brake resistor is as follows:
It is an iterative process because the energy calculated and resistor value may not be available in market or else you have to go for customized solution.
First, calculate the energy to be dissipated in the brake resistor under worst case.
Lets say V1 is the maximum voltage across the dc capacitor and V2 is the voltage up to which we have discharge the dc capacitor from V1 .
Energy, E= C/2(V1^2-V2^2).........................(1) C= DC capacitor value
Now, as per basic power dissipation equation,
P= V^2/R..................(2) where R= brake resistor value.
Worst condition scenario is when we dissipate maximum system energy to brake. That means when we discharge the dc capacitor from maximum voltage to zero volts.
In worst case, V1=V= maximum dc voltage. and V2=0.
From these two equations, you can calculate the maximum energy to be dissipated and resistor vale.
E= P*ton............. (3)where ton= time in which energy is dissipated in resistor. (it could be a single ON pulse or series of ON and OFF pulse).
If you put equation 1 and 2 in 3, you will get a expression as,
For ton, you need to decide your PWM pulse width which may be single pulse or multiple pulse.
First, you calculate the resistor value considering single pulse (as per the ton of decided switching frequency) and check with resistor vendor along with your ambient temperate and enclosure.
If the resistor temperature is too then go for multiple pulse and see the temperature profile.
By this iterative process, you will get you desired brake resistor value.
I hope you understood.
Hello, thanks for your replies! I have a crucial doubt about the IGBT datasheet
In the Datasheet of AUIRGPS4070D0, the Ic current is rated for 240A at 25 degrees, however, due to the anti-parallel diode, it was shown that the nominal current is 120A.
In another datasheet from a different manufacturer, this discrepancy was attributed due to the bond wire of the device.
Is there an exact way to know what the device's ratings are in terms of the bond wire's capabilities?
Also, please recommend any Infineon alternates to the aforementioned Infineon IGBT, ratings are 600/650V and current-carrying capability of at least 220A
The IGBT which you are looking , may I know its application and do you need nominal current as 220 A and at what temperature.
The application is a PMSM Motor Drive. Nominal current considerations would be 220A at 100 Degrees. Preferably with a breakdown voltage of 600 or above.
Could you also comment on the bond wire query as well? Thanks and Regards
FF300R07ME4 is the part number with 650V ,300A, 175 degree operation rating and is suitable for motor dives application. For your convenience, I have attached the data sheet link as well.
Regarding bond wire, I will get back to you soon.
Hello, thanks for the IGBT Module! I have a query from the Reference design 22kW REF-22K-GPD-INV-EASY3B - Infineon Technologies you had provided earlier, in the schematic design of the same.
In the design of the Isolated Supply to the Gate Drivers, is this supply schematic generating voltages of +15V and -15V, or just +15V? Thanks and Regards
It is giving just 15V output out of flyback converter.
Since, we discussed so much variety of design, may I know was is the status of your design and is it really helping you to proceed in right direction.
Hello, thanks for your timely responses!
Thanks for your technical support all along in the design, it was really beneficial, and the current status is the design of the Gate Driver supplies is ongoing, I'm looking for various reference designs to provide my 6 gate drivers with appropriate positive and negative voltages for the application.
There are gate drivers available which have fault reporting, for example the EiceDRIVERs 1ED38x0M12 (X3-digital), 1ED34xMx12M (X3-analog), 1ED332xMC12N, and others
Hello, thanks for the Gate Driver. Could you please answer the other queries as well? Thanks and Regards.
The better way to compare the performance of the multiple gate driver ICs is to test them in the same application board. But, many times it is not possible and therefore all the elements that affect the turnon and turn-off of the power device need to be understood. One key element that has not been discussed so far is an external gate resistor that is used between the output of the gate driver IC and the power device. The value of this gate resistor greatly affects the performance of the system. For example, if the system uses a 20Ω external gate resistor then the
performance of the system might not be significantly affected whether a 2A or 3A gate drive is used at 10V of bias voltage. It should also be noted that even if there is a difference in system performance due to relatively big difference in the drive current capability, this difference can be compensated by adjusting the gate resistor value. For example, 10Ω gate resistor for a 3A driver can be changed to a lower value resistor for a 2A gate driver or higher value resistor for a 4A driver, to achieve the same rise and fall time of the power device. In summary, design engineers need various factors to compare multiple gate drivers' drive strength. These factors are type of switching power device, gate charge of the power device, external gate resistor, test conditions, bias voltage, and operating temperature.
Isolated gate drivers provide level shifting, isolation, and gate drive strength in order to operate power devices. The isolated nature of these gate drivers allows for high-side and low-side device driving, as well as being able to provide a safety barrier if a suitable device is used. An example application is shown in Figure 1. VDD1 and VDD2 are on separate ground references, and the voltages of each may be different. Pin 1 through Pin 3 will be referred to as the primary side, and Pin 4 through Pin 6 will be referred to as the secondary side throughout this article. The isolation provided by the gate drivers can easily be in the hundreds of volts, allowing for higher system bus voltages.
A suitable isolated gate driver must be able to reproduce the timing presented on the primary side and drive the gate of the power device fast enough that switching transitions are acceptable. Faster switching transitions can lead to lower switching losses, so the ability to switch quickly is often a sought-after trait. As a general rule, within one type of switch technology, the larger the power a power device can handle, the larger a load it presents to the gate driver.