描述

5SHX1445H0001 MOS來控制晶體管的新型電力電子器件

眾所周知，IGBT是一種用MOS來控制晶體管的新型電力電子器件，具有電壓高、電流大、頻率高、導(dǎo)通電阻小等特點，被廣泛應(yīng)用在變頻器的逆變電路中。但由于IGBT的耐過流能力與耐過壓能力較差，一旦出現(xiàn)意外就會使它損壞。為此，必須對IGBT進行相關(guān)保護。一般我們從過流、過壓、過熱三方面進行IGBT保護電路設(shè)計。

IGBT承受過電流的時間僅為幾微秒，耐過流量小，因此使用IGBT首要注意的是過流保護。那么該如何根據(jù)IGBT的驅(qū)動要求設(shè)計過流保護呢?

IGBT的過流保護可分為兩種情況：(1)驅(qū)動電路中無保護功能;(2)驅(qū)動電路中設(shè)有保護功能。對于第一種情況，我們可以在主電路中要設(shè)置過流檢測器件;針對第二種情況，由于不同型號的混合驅(qū)動模塊，其輸出能力、開關(guān)速度與du/dt的承受能力不同，使用時要根據(jù)實際情況恰當選用。對于大功率電壓型逆變器新型組合式IGBT過流保護則可以通過封鎖驅(qū)動信號或者減小柵壓來進行保護。

過壓保護則可以從以下幾個方面進行：

●盡可能減少電路中的雜散電感。

●采用吸收回路。吸收回路的作用是;當IGBT關(guān)斷時，吸收電感中釋放的能量，以降低關(guān)斷過電壓。

●適當增大柵極電阻Rg。

IGBT的過熱保護一般是采用散熱器(包括普通散熱器與熱管散熱器)，并可進行強迫風(fēng)冷。

新舊型對比
編輯 播報

在傳統(tǒng)的使用和設(shè)計IGBT的過程中，基本上都是采用粗放式的設(shè)計模式，所需余量較大，系統(tǒng)龐大，但仍無法抵抗來自外界的干擾和自身系統(tǒng)引起的各種失效問題。那么該如何突破傳統(tǒng)的IGBT系統(tǒng)電路保護設(shè)計來解決上述問題呢?

傳統(tǒng)保護模式

防護方案防止柵極電荷積累及柵源電壓出現(xiàn)尖峰損壞IGBT——可在G極和E極之間設(shè)置一些保護元件，如圖1的電阻RGE的作用，是使柵極積累電荷泄放(其阻值可取5kΩ);兩個反向串聯(lián)的穩(wěn)壓二極管V1和V2，是為了防止柵源電壓尖峰損壞IGBT。另外，還有實現(xiàn)控制電路部分與被驅(qū)動的IGBT之間的隔離設(shè)計，以及設(shè)計適合柵極的驅(qū)動脈沖電路等。然而即使這樣，在實際使用的工業(yè)環(huán)境中，以上方案仍然具有比較高的產(chǎn)品失效率——有時甚至?xí)?%。相關(guān)的實驗數(shù)據(jù)和研究表明：這和瞬態(tài)浪涌、靜電及高頻電子干擾有著緊密的關(guān)系，而穩(wěn)壓管在此的響應(yīng)時間和耐電流能力遠遠不足，從而導(dǎo)致IGBT過熱而損壞。

5SHX1445H0001 MOS來控制晶體管的新型電力電子器件

As we all know, IGBT is a new type of power electronic device using MOS to control transistors, with high voltage, high current, high frequency, small on-resistance and other characteristics, is widely used in the inverter inverter circuit. However, due to the poor over-current resistance and over-pressure resistance of IGBT, once an accident occurs, it will be damaged. Therefore, the IGBT must be protected. Generally, we design IGBT protection circuit from three aspects: overcurrent, overvoltage and overheating.

The time of IGBT to withstand overcurrent is only a few microseconds, and the over-flow resistance is small, so the first thing to pay attention to when using IGBT is overcurrent protection. So how to design overcurrent protection according to the driving requirements of IGBT?

The over-current protection of IGBT can be divided into two cases: (1) there is no protection function in the drive circuit; (2) The protection function is provided in the drive circuit. For the first case, we can set the overcurrent detection device in the main circuit; For the second case, due to the different types of hybrid drive module, its output capacity, switching speed and the bearing capacity of du/dt are different, and it should be properly selected according to the actual situation. The new combined IGBT overcurrent protection for high-power voltage inverters can be achieved by blocking the drive signal or reducing the gate voltage.

Overvoltage protection can be carried out from the following aspects:

● Reduce stray inductance in the circuit as much as possible.

● Absorption loop is adopted. The role of the absorption loop is; When the IGBT is turned off, the energy released in the inductor is absorbed to reduce the turn-off overvoltage.

● Appropriately increase the grid resistance Rg.

The overheating protection of IGBT is generally the use of radiators (including ordinary radiators and heat pipe radiators), and can be forced air cooling.

Contrast between old and new types
Editorial broadcast

In the process of traditional use and design of IGBT, basically the extensive design mode is used, the required margin is large, the system is huge, but it is still unable to resist the interference from the outside world and various failure problems caused by its own system. So how to break through the traditional IGBT system circuit protection design to solve the above problems?

Traditional protection mode

Protection scheme to prevent grid charge accumulation and gate source voltage spike damage IGBT – some protection elements can be set between the G and E poles, the role of the resistance RGE in Figure 1 is to make the grid accumulated charge discharge (its resistance value can be 5kΩ); Two voltage regulator diodes V1 and V2 are in series in reverse to prevent gate source voltage spikes from damaging the IGBT. In addition, the isolation design between the control circuit and the driven IGBT and the drive pulse circuit suitable for the grid are also designed. However, even so, in the actual industrial environment, the above solution still has a relatively high product failure rate – sometimes even more than 5%. Relevant experimental data and research show that this is closely related to transient surge, static electricity and high-frequency electronic interference, and the response time and current resistance of the regulator in this is far from enough, resulting in overheating and damage of IGBT.

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Company Introduction:
Chengdu Sunshine Xihe Co., Ltd. specializes in one-stop procurement consulting for imported industrial spare parts, offering original equipment and professional discontinued parts services. We are committed to providing efficient and reliable automation solutions for our customers. Customer support fast responseThe network of partners spans all continentsGlobal partner networkAlways achieve more delivery, be it parts, service or speed



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