IR2132 Driver and Its Application in Three-Phase Inverter

0 Introduction

Inverters have been widely used in many technical fields such as AC electric transmission and UPS. The main circuit switch devices often use fully controlled devices such as IGBT, MOSF, ET, etc. The switching action of such devices needs to be realized by independent drive circuits, and the power supply of the drive circuits needs to be isolated from each other (such as single-phase bridge inverter main circuit requires 3 sets of independent power supplies, and three-phase bridge inverter main circuit requires 4 sets of independent power supplies). This undoubtedly increases the difficulty and cost of auxiliary power supply design, and also makes the drive circuit complicated and reduces the reliability of the inverter. Although the use of special thick film integrated drive circuit chips such as EXB840 can simplify the design of the drive circuit, each drive chip still requires an isolated power supply, and each chip can only drive one power switch device, which is still inconvenient in application. The special drive chip IR2132 produced by International Rectifier Corporation of the United States only needs one power supply to drive the six power switch devices of the three-phase bridge inverter circuit, which can make the entire drive circuit simple and reliable.

1 Characteristics of IR2132 driver chip

IR2132 can be used to drive power MOS gate devices in circuits with bus voltage not higher than 600 V. The maximum forward peak drive current it can output is 250 mA, while the reverse peak drive current is 500 mA. It is designed with overcurrent, overvoltage and undervoltage protection, blocking and indication networks, so that users can easily use it to protect the driven MOS gate power tube. In addition, the clever use of internal bootstrap technology allows it to be used in high-voltage systems. It can also generate 0.8μs interlocking delay time for the gate drive signals of the upper and lower power devices of the same bridge arm. It has a wide range of its own working and power supply voltage (3 to 20 V). It is also designed with a current amplifier that is linearly related to the current passing through the driven power device. The circuit design also ensures that the internal three-channel high-side driver and low-voltage side driver can be used separately, or only the three internal low-voltage side drivers can be used, and the input signal is compatible with TTL and CMOS levels. The IR2132 pin is shown in Figure 1. VBl~VB3 are the floating power supply ground terminals, which provide internal floating power supply for the drivers of the three upper bridge arm power tubes through bootstrap capacitors, and VSl~VS3 are their corresponding floating power supply ground terminals.

• HIN1~HIN3, LIN1~LIN3 are the driving signal input terminals of the upper bridge arm and lower bridge arm of the inverter, and low level is valid.
• ITRIP is the overcurrent signal detection input terminal, which can complete overcurrent or shoot-through protection through the input current signal.
• CA1, CA0, and VSO are the inverting terminal, output terminal, and non-inverting terminal of the internal amplifier, which can be used to complete current signal detection.
• H01~H03, L01~L03 are the drive signal output terminals of the upper and lower bridge arm power switch devices of the inverter.
• FAULT is the overcurrent, short circuit, overvoltage, and undervoltage protection output terminal, which provides a fault protection indication signal. It is an open-drain output terminal inside the chip, and low level is effective.
• VCC and VSS are the power supply connection terminals of the chip, VCC is connected to the positive power supply, and VSS is connected to the power ground.

2 IR2132 internal structure and working principle

The internal structure of IR2132 is shown in Figure 2. It integrates 1 current comparator, 1 current amplifier, 1 under voltage detector of its own working power supply, 1 fault processing unit and 1 clearing and blocking logic unit. In addition to the above, it also integrates 3 input signal processors, 2 pulse processing and level shifters, 3 upper bridge arm side power tube drive signal latches, 3 upper bridge arm side power tube drive signals and under voltage detectors, 6 low output impedance MOS power tube drivers and 1 OR gate circuit.

During normal operation, the 6 input drive signals are processed by the input signal processor and converted into 6 output pulses. The signals L1 to L3 driving the lower bridge arm power tube are directly sent to the driven power device after being amplified by the output driver. The signals H1 to H3 driving the upper bridge arm power tube are first transformed by the bootstrap circuit in the 3 pulse processors and level shifters integrated in the IR2132 to become 3 potential suspended drive pulses, and then latched by the corresponding 3 output latches and strictly tested for drive pulses before being sent to the output driver for amplification before being added to the driven power tube. Once the external current is overcurrent or direct current, that is, the signal sent by the current detection unit is higher than 0.5 V, the current comparator inside the IR2132 quickly flips, prompting the fault logic unit to output a low level, and the output of the 3 input pulse signal processors is blocked, so that the output of the IR2132 is all low level to protect the power tube; at the same time, the FAULT pin of the IR2132 gives a fault indication. Similarly, if the working power supply of IR2132 is undervoltage, the undervoltage detector will flip quickly and perform similar actions. After a fault occurs, the output of the fault logic unit in IR2132 will remain in the fault latched state. The fault latched state can only be released when a high level is input to the signal input terminals LIN1~LIN3 at the same time after the fault is cleared.

When the bootstrap power supply voltage of the upper bridge arm power tube driven by IR2132 is insufficient, the drive signal detector of the circuit will act quickly to block the output of this path to prevent the power device from being damaged due to insufficient drive signal. When the input signals of the two power devices on the same bridge arm of the inverter are high at the same time, the two gate drive signals output by IR2132 are all low, thus reliably avoiding the occurrence of bridge arm shoot-through phenomenon.

3 Inverter circuit structure using IR2132

3.1 Control circuit

A new type of digital control scheme of prefabricated phase PWM wave is adopted. The switching state of the six switching tubes of the inverter corresponds to the SPWM pulse of a certain modulation ratio. The starting point is that an EP-ROM is used to store the switching state of the six switching tubes. The pre-set in the EPROM is generated by various methods. The common method is to calculate it first, corresponding to different fundamental frequencies, and calculate the corresponding pulse width according to a certain rule, and then convert it into a numerical value and store it in the EPROM. The output of the EPROM is connected to HINl~HIN3 and LINl~LIN3 of IR2132. The phase difference between the switches in the same bridge arm is 120°, and the upper and lower switches in the same bridge arm are complementary and have a dead zone. The principle of its SPWM wave generation circuit is shown in Figure 3.

3.2 Driving circuit

When the IR2132 chip is used to drive the inverter power tube, its basic main circuit does not need to be changed, and the typical three-phase voltage type inverter circuit can still be used. For the convenience of representation, Figure 4 shows the circuit diagram of one bridge arm in the IR2132 drive. In the figure, C1 is a bootstrap capacitor, which stores energy for the floating power supply driven by the upper bridge arm power tube. The function of VD1 is to prevent the DC voltage bus voltage from being added to the power supply of IR2132 when the upper bridge arm is turned on, which may damage the device. Therefore, VD1 should have sufficient reverse withstand voltage. Of course, since VD1 is connected in series with C1, in order to meet the switching frequency requirements of the main circuit power tube, VD1 should be a fast recovery diode. R1 and R2 are the gate drive resistors of the IGBT, which can generally be 10 to tens of ohms. R3 and R4 form an overcurrent detection circuit, in which R3 is an overcurrent sampling resistor and R4 is an adjustable resistor used as a voltage divider. HINl~HIN3 and LINl~LIN3 of IR2132 are connected to the EPROM of the SPWM wave generation circuit as input drive signals of the power tube. Its capacity depends on the switching frequency, duty cycle and charging circuit resistance of the driven power device. It is necessary to ensure that the capacitor is charged to a sufficient voltage, and the voltage across it is not lower than the undervoltage protection action value when discharging. When the driven switching frequency is greater than 5 kHz, the capacitance value is not less than 0.1 μF, and ceramic capacitors are preferred.

4 Conclusion

The IR2132 device is used to drive a three-phase inverter powered by a single-chip power supply. As long as the floating charge capacitor is selected reasonably, the drive circuit will work very reliably. It not only simplifies the circuit structure and improves reliability, but also can reliably implement fault protection such as short circuit, overcurrent, undervoltage and overvoltage.