The direct function of t爸一he inverter is to transform the DC頻行 power into the core of th在章e AC power inverter, which 看生is the inverter switch circuit, 在時referred to as the inverter circuit.能技

  The circuit completes the還月 function of inverter跳遠 through the on and o書森ff of power electronic switch. The on-購外off of power electronic swi如服tching devices requires certain森朋 driving pulses, which may b朋風e regulated by changing a厭時 voltage signal. A ci哥化rcuit that generates an資船d modulates pulses. Us做員ually called control circuit or cont花照rol loop. The basic structure刀都 of the inverter device, in addi術多tion to the above inverter circuit and業討 control circuit, the物筆re are protection circuit, output ci民兵rcuit, input circuit, outpu章物t circuit, etc., as shown in F什快igure 2. Working principle of inve暗拿rter.

  1. The working prin能風ciple of full control inverter is t新林he main circuit of single-phase o和章utput full bridge inverter, an來還d the AC components ar筆事e IGBT tubes Q11, Q1照子2, q13 and q14. PWM is used to 喝身control the on or off of IGBT.不和

  When the inverter circuit is c算書onnected to the DC power supp購但ly, it is first turned on 玩錢by Q11 and q14, and then cut o票術ff by Q1 and q13, then the cur但技rent is output by the pos章頻itive pole of the DC power su歌算pply, and then returne林子d to the negative pole of the p匠北ower supply through Q11, l or the prim舊美ary coil Figure 1-2 of the inductor 明長and transformer. When Q11 and q14 ar說舞e cut off, Q12 and q13 are聽討 connected, and the current flo文男ws from the positive pole of the 女答power supply to the negative pole慢影 of the power supply through the indu女算ctance of q13 and the拿場 primary coil 2-1 of the transfo黑國rmer. At this time, a posi店用tive and negative alternating square w如就ave has been formed on the primary coi化城l of the transformer. By 火冷using high frequency PWM con車歌trol, two pairs of IGB電慢T tubes are alternately repeated to 拍雨generate alternating v從音oltage on the transformer. Because of長新 the function of LC AC f很坐ilter, sine wave AC vo下樂ltage is formed at the output子去.

  When Q11 and q14 are turned of東購f, in order to release the stored 北森energy, the secondary tubes D11 and 嗎器D12 are connected in parallel 門船at the IGBT to return the energy去高 to the DC power supply.

  2. Working princi車吧ple of half control i樹拍nverter: the half control inverte白船r adopts thyristor elem能爸ent. The main circuit of the improved p窗師arallel inverter is shown in Figure 4. 小技In the figure, Th1 and Th2 are thyristo技事rs that work alternate妹聽ly. If Th1 is set to trigg就件er conduction first, the current 服什will flow through Th1 through the區他 transformer. At the same time, due 服呢to the induction of the老們 transformer, the reversing 月國capacitor C will be 務生charged to twice the power sup內了ply voltage. According 北器to Th2, it is triggered to turn on對快. Because the anode of Th2遠熱 is applied with reverse bias volt國黃age, Th1 is cut off and returns to 爸謝the blocking state. In this way你知, Th1 and Th2 are switched, and t一音hen capacitor C is charged in reverse國空 polarity. In this way,林老 the thyristor is triggered alt月鐵ernately, and the current flows altern關訊ately to the primary 媽房of the transformer, where the alternat草了ing current is obtained.

  In the circuit, the inducta照那nce L can limit the discharge curren飛看t of the commutating 裡男capacitor C, extend the discharge t睡東ime, and ensure that the o年玩ff time of the circuit i兒裡s longer than the off tim作話e of the thyristor, 音哥without the need for a capacitor with l媽話arge capacity. D1 and D2 are時科 two feedback diodes, which ca年吧n release the energy in inductan熱兒ce L, return the residual購是 energy of commutation to the power su那資pply, and complete the energy f們樂eedback.