[introduction]Compressor is the one part of car air conditioning, it compresses the gas of high temperature high pressure through will making cryogen, shed classics condenser again, throttle and evaporator heat exchange, realize the cold hot exchange of car inside and outside. Traditional fuel car is motivation with engine, drive compressor to turn through leather belt. And car of new energy resources broke away from engine, it is motivation with batteries, do not have through inversion circuit drive brush dc machine, drive compressor to turn thereby, the cold heat that realizes air conditioning exchanges a function.

  

Compressor is the one part of car air conditioning, it compresses the gas of high temperature high pressure through will making cryogen, shed classics condenser again, throttle and evaporator heat exchange, realize the cold hot exchange of car inside and outside. Traditional fuel car is motivation with engine, drive compressor to turn through leather belt. And car of new energy resources broke away from engine, it is motivation with batteries, do not have through inversion circuit drive brush dc machine, drive compressor to turn thereby, the cold heat that realizes air conditioning exchanges a function.

Electric compressor is the core part that electric car heat manages, besides can raise the environmental easy inside railroad car measurable (refrigeration, make heat) beyond, to the temperature of electric drive system control is producing main effect, the service life to batteries, charge speed and add boat course of development are crucial.

Graph 1: Electric compressor is the core part that electric car heat manages

Electric compressor needs to satisfy the requirement that raises ceaselessly, include level of low cost, smaller size, fewer vibration and noise, higher power and more high-energy effect. These demand cannot leave the type selecting of the design of compressor drive circuit and outstanding parts of an apparatus.

Function of electric compressor controller includes: Drive electric machinery (inversion circuit: Include ASPM module or schism parts of an apparatus carries door pole drive, voltage / electric current / temperature detects reach protection, power source is changed) , with lead plane communication (CAN or LIN, receive open stop and rotate speed signal, send moving condition and fault signal) etc, ansenmei (Onsemi) has corresponding solution in every circuit (graph 1) . Article key discusses plan of module of inversion circuit ASPM.

Graph 2: Circuit of electric compressor drive controls block diagram

Module of power of intelligence of ASPM car class    

 

Module of power of car class intelligence (Automotive Smart Power Module, ASPM) be a kind compositive circuit of power semiconductor device, drive and the module that dominate circuit change a solution, aim to offer efficient, reliable, compact electric power changeover and control.

Graph 3: Ansenmei (the ASPM27(of Onsemi) is left) with ASPM34(right)

The advantage of module of power of intelligence of ASPM car class

On the frame citing a base that chip of ASPM module power and IC chip are soldered to pledge to copper directly, enclothe the frame that cite a base with pottery and porcelain then, the mould in putting epoxy resin finally shapes. Photograph score reduced parasitism inductance greatly for cubic case, the area that board place of the amount of the parts of an apparatus that reduced integral design and PCB requires, offer tall insulation compression and can maintain good medicinal powder hot property.

Graph 4: ASPM internal composition

1. cost

If compare the cost of parts of an apparatus of ASPM module and schism parts of an apparatus alone,go up in cost, the cost of module will be higher. But come from whole system cost say, considering PCB, mechanical installation, quality and property cost, systematic power is higher, use ASPM module can have an advantage more.

2. heats up function

Graph 5: The hot property dominant position of ASPM

In the design of electric compressor, medicinal powder hot character is a crucial factor, it affects the voltaic carrying capacity of module directly. Accordingly, enclose medicinal powder when hot character is deciding its function is behaved crucial. Coming loose hot character, enclose dimension and segregation there is balance to concern between character. The outstanding key that encloses a technology depends on, optimize enclose dimension, keep outstanding at the same time medicinal powder hot property, and do not sacrifice segregation grade.

With 650V ASPM27 the department is labelled exemple, these module used DBC (Fu copperplate) substrate technology, brought come loose goodly hot property. Power chip is stuck directly outfit go up in DBC substrate, make quantity of heat can be conducted effectively from chip to exterior, rose to come loose thereby thermal efficiency and dependability, the long-term stability that this issues to maintaining power module to work in big electric current and prolong service life crucial.

Because temperature affects the function of the product, dependability and life directly, so most architect hopes to understand the temperature of power chip accurately. However, because enclose in-house power chip (be like IGBT, FRD) work below high-pressured condition, measure its temperature to become relatively difficult directly. In the past, as a result of cost and technical reason, the architect often is not the temperature that measures power chip directly, the NTC thermal resistor of the buy outside be being used however goes detecting the temperature of module or radiator, although this kind of method is simple, but not the temperature circumstance of itself of component of power of can accurate report. And in 1200V ASPM34 series, the one big innovation on the design is nodded even if NTC thermal resistor and power chip compositive go up in substrate of same pottery and porcelain, implementation undertakes temperature sampling in module interior. Come so, can reflect the actual temperature condition that gives power chip well and truly, the knowing that makes a hair personnel clear quantity of abundant of module interior temperature, make corresponding step in systematic control, it is for instance when low rotate speed, the system comes loose heat is bad to bring about module temperature exorbitant, can increase frequency appropriately, strengthen medicinal powder hot; Perhaps reduce frequency to perhaps had done Wen Ting machine to protect appropriately when high frequency high-power. The switch frequency design of ASPM module of Ansenmei is as high as 20kHz above (ASPM27-V3 can amount to 40kHz, the IGBT switch rate of FS4 is rapidder, Switch lossLower) , can answer existing and electric compressor easily 15000 turn / minute requirement of the following rotate speed sampling.

Graph 6: Block diagram of ASPM27 in-house circuit

3. power density

ASPM photograph is greater than schism IGBT plan of degree reduced circuit inductance, need not consider the electric and safe distance between schism parts of an apparatus; Bring foot and medicinal powder the insulation that 2500V is as high as between hot side, need not resemble IGBT in that way must additional increase insulation spacer. And installation is convenient, reliability is high.

Graph 7: ASPM plan establishs the power density of IGBT plan to score

4. dependability

ASPM module is compositive optimized protective circuit and the drive that match with photograph of IGBT switch feature, circuit matchs and can develop time with shortening for developer huge. Through compositive owe control protective function and function of short circuit protection, systematic dependability got very old rate rise. HVIC of buy high speed has the capacity of counteractive Dv/dt and negative pressure inside, offerred a kind need not the IGBT drive ability that smooth Ou keeps apart. The develop that compositive HVIC allows to use the drive of only power source that need not lose power source attacks.

Graph 8: HVIC has counteractive Dv/dt and negative pressure capacity

Want to realize higher reliability, can reduce the Mismatch of the CTE between different material as far as possible. ASPM module of Ansenmei passes AEC-Q and AQG324 attestation, schism parts of an apparatus undertakes attestation according to AECQ100/101. We also can consider to undertake according to the client’s specific requirement a few special dependability check.

Trend and challenge

The need when the electric compressor that falls for high-pressured environment chooses power parts of an apparatus considers the idea that abundant measures, the voltage wave motion that in order to ensure enough secure room answers all sorts of conditions to fall and transient state incident.

Make rich the quantity is to be based on the following kinds of considerations normally:

Abundant of voltage of 1. stable state measures: Below regular job status, wait for an element considering voltage wave motion, laden change, working voltage can let normally when the design under power parts of an apparatus nominal compression value, for instance if batteries system highest voltage is 400V, criterion the voltage abundant amount that the parts of an apparatus of 650V compression provided 250V.

Abundant of voltage of 2. transient state measures: Be operated in switch or electrified wire netting is unusual wait for a circumstance to fall, may appear voltage aiguille of the instant, right now abundant quantity is used assure to be in these are brief but below strong voltage impact, parts of an apparatus won’t by puncture.

Abundant measures 3. dependability: In running a course for a long time, the compression function of power parts of an apparatus may drop gradually because of the element such as temperature, ageing, because this offers enough voltage to make rich the quantity conduces to,prolong life of parts of an apparatus, promote the reliability of whole system.

The power parts of an apparatus of 650V compression is applying at peak value voltage is close to the system of its rating, architect need evaluates voltage carefully abundant capacity is sufficient, ensure the operation condition that is in all anticipation falls, power parts of an apparatus works steadily. As the development of electric car technology, batteries voltage platform rises ceaselessly, the peak value voltage of the 400V platform of some cars look forward to achieved 500V above, be in when original 650V ASPM module below new applied situation when abundant capacity is insufficient, the ASPM module that can drive the market and technology to be like 750V to taller compression grade develops.

In 800V platform, because take measure of the compressor that use a car smaller, difficulty of design of the PCB when choosing 1200V module is opposite bigger, because the compressor of miniaturization is in-house the space is limited, the need when the PCB overall arrangement that devises tall voltage grade ensures crucial yuan there is enough electric and safe space between parts of an apparatus, the power that this encloses to high density is a challenge for module. The loss that module produces when tall voltage come off work is made is bigger, need comes loose efficiently hot plan, and the design may restrict miniaturization to come loose hot area and medicinal powder the design of hot method, those who increased heat management design is complex degree. Tall voltage grade means taller electromagnetism to violate a venture, need more meticulous PCB to take line design and screen step, in order to accord with relevant electromagnetism compatible standard. Still need to ensure in tall voltage the level falls, the insulation property of PCB amounts to mark, prevent to climb the happening of the problem such as report, puncture. Tall voltage and big electric current transmit needs circuit width, span and number of plies to increase possibly, also need to consider to reduce at the same timeParasitism parameterinfluence, be like inductance and resistor, with optimizing switch function is mixed reduce loss. Be aimed at these challenges and demand, ansenmei is about to roll out next generation the 1200V module of smaller size, the FS7 IGBT with compositive and newest interior, settle afore-mentioned challenges, come true more optimized function, the area narrowed 36% , and still roseInsulation compressionCharacteristic, the design that is electric compressor controller brings more promotion.

                                         

Circuit design and PCB layout Tips

Graph 9: 650V ASPM27 series uses circuit figure

The parameter of parts of an apparatus of graphic representation consults series of module of power of intelligence of 650V ASPM27 car uses manual please.

To the design proposal of PCB Layout:

Ground of power of the proposal when 1. is designed and digital ground sheet nod ground connection, ground wire as far as possible short and cannot too wide;

2. sampling resistor is apart from Nu, nv, nw cites a base should as far as possible short, reduce a line to bringParasitism inductance;

Of 3.Csc protection RC take a line should as far as possible short, and the ground of filter wave capacitance had better receive land of power of control ground and rather than;

The absorption of two end of 4.PN capacitance is put in the distance module is closer, the Vce aiguille that arises to IGBT absorbs the effect to had been jumped over;

5. lifts capacitance and stabilized voltage canal to place oneself in the distance module leaves the place with the closest foot, every should consider clearance and requirement of distance climbing report between the road; Fill discharge to let its itself become an interference source from what cite electric capacity, should notice he and other easy the distance between the weak report circuit that is disturbed;

Capacitance of 6. module power supply also should stand by module to cite a base as far as possible;

7. inputs the RC that controls signal Vin to should stand by module to cite a base, mcu of and rather than, ensure the signal that inputs module interior is clean.

Graph 10: Layout of 650 V ASPM27 PCB is designed

Epilogue

ASPM module is a car the control parts of an apparatus of the ideal in the electric machinery control such as electric compressor, water pump; But develop toward taller voltage as car batteries (for instance batteries highest voltage achieves 900V above) , and efficiency demand is higher and higher, use IGBT faces certain limitation as the ASPM of power parts of an apparatus. The IGBT of outclass of compression of itself of SiC parts of an apparatus of identical compression norms, and itsSwitch lossFar under IGBT parts of an apparatus, can get used to higher rotate speed, more efficient requirement.

 

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