CN105141154B - A kind of BJT types single phase full bridge controlled rectifier - Google Patents

Abstract

A kind of BJT types single phase full bridge controlled rectifier, the rectification circuit includes input capacitance Ci, positive-negative-positive BJT pipes Q1, positive-negative-positive BJT pipes Q2, NPN type BJT pipes Q3, NPN type BJT pipes Q4, NPN type BJT pipes Q5, output capacitance Co, diode D1, diode D2, resistance R1, resistance R2, resistance R3 and for by controlling NPN type BJT pipes Q5 base current to realize the controlled current source M1 to the control of positive-negative-positive BJT pipes Q1 and positive-negative-positive BJT pipe Q2 working conditions.The present invention provides a kind of simplified drive circuit, drive efficiency higher BJT type single phase full bridge controlled rectifiers.

Description

A BJT type single-phase bridge fully controlled rectifier circuit

technical field

The invention relates to a rectification (AC-DC) circuit, which is applied to electric energy conversion occasions of AC input and DC output, such as: micro energy collection system, new energy power generation system, battery charging system, etc., especially a single-phase bridge full control rectifier circuit.

Background technique

The rectifier (AC-DC) circuit is a circuit that can convert AC power into DC power, and is widely used. According to the number of AC input phases, the rectifier circuit can be divided into single-phase circuit and multi-phase circuit; according to the circuit structure, the rectifier circuit can be divided into bridge circuit and zero-type circuit; control circuit, half control circuit and full control circuit.

Fully controlled devices suitable for small and medium power applications mainly include MOSFETs and BJTs. In the early days, the BJT of Si material had disadvantages such as large driving loss, high switching loss, and large device dynamic impedance. Therefore, in order to obtain low power consumption, MOSFETs are mostly used in single-phase bridge fully-controlled rectification circuits with low and medium power. However, the MOSFET is a voltage-type driving device, and compared with the current-type driving device BJT, the driving circuit of the MOSFET is more complicated than that of the BJT. Especially in the working environment of ultra-low voltage or high voltage, the design of MOSFET driving circuit is quite difficult.

Contents of the invention

In order to overcome the shortcomings of complex MOSFET drive circuit and low drive efficiency in the existing MOSFET type single-phase bridge fully controlled rectifier circuit, the present invention provides a BJT type single-phase bridge fully controlled rectifier with simplified drive circuit and high drive efficiency circuit.

The technical solution adopted by the present invention to solve its technical problems is:

A BJT type single-phase bridge fully controlled rectifier circuit, the rectifier circuit includes an input capacitor Ci, a PNP type BJT tube Q1, a PNP type BJT tube Q2, an NPN type BJT tube Q3, an NPN type BJT tube Q4, and an NPN type BJT tube Q5, output capacitor Co, diode D1, diode D2, resistor R1, resistor R2, resistor R3 and used to control the base current of NPN type BJT tube Q5 to realize the working state of PNP type BJT tube Q1 and PNP type BJT tube Q2 Controlled current source M1, one end of the input capacitor Ci is connected to the positive end of the single-phase AC power supply vac, the anode of the diode D1, the emitter of the PNP type BJT transistor Q1 and the emitter electrode of the NPN type BJT transistor Q3, and the PNP type The collector of the BJT tube Q1 is connected to one end of the resistor R2, the collector of the PNP type BJT tube Q2, one end of the output capacitor Co, one end of the load Z1, and the positive end of the output voltage vo, and the base of the PNP type BJT tube Q1 is simultaneously It is connected with the base of PNP type BJT tube Q2 and one end of resistor R1, and the emitter of PNP type BJT tube Q2 is connected with the emitter of NPN type BJT tube Q4, the anode of diode D2, the other end of input capacitor Ci and single-phase AC The negative terminal of the power supply vac is connected, and the collector of the NPN BJT tube Q3 is simultaneously connected to the emitter of the NPN BJT tube Q5, the collector of the NPN BJT tube Q4, the other end of the output capacitor Co, the other end of the load Z1, and the output voltage The negative terminal of vo is connected, the collector of NPN type BJT tube Q5 is connected with the other end of resistor R1, the base of NPN type BJT tube Q5 is connected with one end of resistor R3 and port a of controlled current source M1 at the same time, and the terminal of resistor R3 The other end is connected to the cathode of the diode D1 and the cathode of the diode D2 at the same time, and the base of the NPN BJT transistor Q3 is connected to the other end of the resistor R2 and the base of the NPN BJT transistor Q4 at the same time.

Further, an accelerating capacitor C1 is connected in parallel at both ends of the resistor R1, an accelerating capacitor C2 is connected in parallel at both ends of the resistor R2, and an accelerating capacitor C3 is connected in parallel at both ends of the resistor R3. This preferred solution can accelerate the dynamic characteristics of the BJT type single-phase bridge fully controlled rectifier circuit.

Furthermore, the controlled current source M1 includes an NPN type BJT transistor Qa1, a resistor Ra1, a resistor Ra2, a resistor Ra3 and a capacitor Ca1, the collector of the NPN type BJT transistor Qa1 is port a of the controlled current source M1, and the NPN type BJT The emitter of the tube Qa1 is connected to one end of the resistor Ra3, one end of the capacitor Ca1 and the negative end of the output voltage vo at the same time, the base of the NPN type BJT tube Qa1 is connected to one end of the resistor Ra2 and the other end of the resistor Ra3 at the same time, and the resistor Ra2 The other end is connected to one end of the resistor Ra1 and the other end of the capacitor Ca1 at the same time, and the other end of the resistor Ra1 is connected to the cathode of the diode D1. The BJT type single-phase bridge fully controlled rectifier circuit has an input voltage overvoltage protection function.

Furthermore, the controlled current source M1 includes an NPN type BJT transistor Qb1, a diode Db1, a resistor Rb1, a resistor Rb2 and a capacitor Cb1, one end of the load Z1 is connected to the positive end of the output voltage vo, and the other end of the load Z1 is simultaneously connected to the diode The anode of Db1 is connected to one end of resistor Rb1, the collector of NPN type BJT tube Qb1 is port a of controlled current source M1, and the emitter of NPN type BJT tube Qb1 is simultaneously connected to the negative end of output voltage vo, one end of resistor Rb2, One end of the capacitor Cb1 is connected to the other end of the resistor Rb1, and the base of the NPN BJT transistor Qb1 is connected to the other end of the resistor Rb2, the other end of the capacitor Cb1 and the cathode of the diode Db1. The BJT type single-phase bridge fully controlled rectifier circuit has an output current limiting protection function.

The technical idea of the present invention is: with the development of new semiconductor material devices, the BJT of new materials (such as SiC) has shown smaller drive loss, very low resistivity, faster switching speed, lower temperature Dependence, good short-circuit capability and no secondary breakdown and many other advantages. The BJT of new material is used in the single-phase bridge fully controlled rectifier circuit of small and medium power, not only can obtain low power consumption, but also can simplify the driving circuit of the fully controlled device.

The single-phase bridge fully-controlled rectifier circuit adopts BJT, and the advantages of BJT's working performance can realize simple circuit and high efficiency at the same time.

The beneficial effects of the present invention are mainly manifested in that the BJT type single-phase bridge fully-controlled rectifier circuit has the ability to convert AC power into DC power, has simple circuit, high driving efficiency, and is suitable for various control methods.

Description of drawings

Fig. 1 is a schematic diagram of the basic circuit structure of the present invention.

Fig. 2 is a schematic diagram of the circuit structure of the accelerated dynamic characteristic of the present invention.

Fig. 3 is a circuit diagram of Embodiment 1 of the present invention.

Fig. 4 is a circuit diagram of Embodiment 2 of the present invention.

FIG. 5 is a simulation working waveform diagram when the output capacitor Co is small in Embodiment 1 of the present invention.

FIG. 6 is a simulation working waveform diagram when the output capacitor Co is small in Embodiment 2 of the present invention.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings.

Referring to Figures 1 and 2, a BJT type single-phase bridge fully controlled rectifier circuit, the rectifier circuit includes an input capacitor Ci, a PNP type BJT tube Q1, a PNP type BJT tube Q2, an NPN type BJT tube Q3, and an NPN type BJT tube Tube Q4, NPN type BJT tube Q5, output capacitor Co, diode D1, diode D2, resistor R1, resistor R2, resistor R3 and are used to control the base current of NPN type BJT tube Q5 to achieve the PNP type BJT tube Q1 and PNP A controlled current source M1 for controlling the working state of the type BJT tube Q2, one end of the input capacitor Ci is simultaneously connected with the positive end of the single-phase AC power supply vac, the anode of the diode D1, the emitter of the PNP type BJT tube Q1 and the NPN type BJT tube Q3 The emitter of the PNP type BJT tube Q1 is connected to the collector of the PNP type BJT tube Q1 at the same time. The base of the BJT tube Q1 is connected to the base of the PNP type BJT tube Q2 and one end of the resistor R1 at the same time, and the emitter of the PNP type BJT tube Q2 is simultaneously connected to the emitter of the NPN type BJT tube Q4, the anode of the diode D2, and the input capacitor Ci The other end of the single-phase AC power supply vac is connected, and the collector of the NPN BJT tube Q3 is connected to the emitter of the NPN BJT tube Q5, the collector of the NPN BJT tube Q4, the other end of the output capacitor Co, and the load The other end of Z1 is connected to the negative end of the output voltage vo, the collector of the NPN BJT transistor Q5 is connected to the other end of the resistor R1, and the base of the NPN BJT transistor Q5 is connected to one end of the resistor R3 and the controlled current source M1 at the same time. The port a is connected, the other end of the resistor R3 is connected to the cathode of the diode D1 and the cathode of the diode D2 at the same time, the base of the NPN BJT transistor Q3 is connected to the other end of the resistor R2 and the base of the NPN BJT transistor Q4 at the same time.

Further, an accelerating capacitor C1 is connected in parallel at both ends of the resistor R1, an accelerating capacitor C2 is connected in parallel at both ends of the resistor R2, and an accelerating capacitor C3 is connected in parallel at both ends of the resistor R3. This preferred solution can accelerate the dynamic characteristics of the BJT type single-phase bridge fully controlled rectifier circuit.

Embodiment 1: Referring to Fig. 1, Fig. 3 and Fig. 5, Embodiment 1 of the present invention has an input voltage overvoltage protection function, which consists of an input capacitor Ci, a PNP type BJT tube Q1, a PNP type BJT tube Q2, and an NPN type BJT tube Q3 , NPN type BJT tube Q4, NPN type BJT tube Q5, output capacitor Co, diode D1, diode D2, resistor R1, resistor R2, resistor R3, controlled current source M1. Wherein, the controlled current source M1 is composed of an NPN type BJT transistor Qa1, a resistor Ra1, a resistor Ra2, a resistor Ra3, and a capacitor Ca1.

As shown in Figure 3, one end of the input capacitor Ci is simultaneously connected to the positive end of the single-phase AC power supply vac, the anode of the diode D1, the emitter of the PNP BJT transistor Q1, and the emitter of the NPN BJT transistor Q3. The collector of Q1 is connected to one end of resistor R2, the collector of PNP type BJT tube Q2, one end of output capacitor Co, one end of load Z1 and the positive end of output voltage vo, and the base of PNP type BJT tube Q1 is connected to PNP type BJT tube Q1 at the same time. The base of the type BJT tube Q2 is connected to one end of the resistor R1, and the emitter of the PNP type BJT tube Q2 is connected to the emitter of the NPN type BJT tube Q4, the anode of the diode D2, the other end of the input capacitor Ci and the single-phase AC power supply vac The negative terminal of the NPN BJT tube Q3 is connected to the collector of the NPN BJT tube Q5, the collector of the NPN BJT tube Q4, the other end of the output capacitor Co, the other end of the load Z1 and the output voltage vo The negative terminal is connected, the collector of NPN type BJT tube Q5 is connected to the other end of resistor R1, the base of NPN type BJT tube Q5 is connected to one end of resistor R3 and port a of controlled current source M1 at the same time, the other end of resistor R3 At the same time, it is connected to the cathode of diode D1 and the cathode of diode D2. The base of NPN BJT transistor Q3 is connected to the other end of resistor R2 and the base of NPN BJT transistor Q4 at the same time. The collector of NPN BJT transistor Qa1 is controlled The port a of the current source M1, the emitter of the NPN type BJT transistor Qa1 are simultaneously connected to one end of the resistor Ra3, one end of the capacitor Ca1 and the negative end of the output voltage vo, and the base of the NPN type BJT transistor Qa1 is simultaneously connected to one end of the resistor Ra2 and The other end of the resistor Ra3 is connected, the other end of the resistor Ra2 is connected to one end of the resistor Ra1 and the other end of the capacitor Ca1, and the other end of the resistor Ra1 is connected to the cathode of the diode D1.

Fig. 5 is the simulation working wave diagram when the capacitance value of the output capacitor Co is small in Embodiment 1 of the present invention, and its steady-state working principle is as follows:

When vac<0, the single-phase AC power supply vac is in the negative half cycle (ie ta1<t<ta4); when vac>0, the single-phase AC power supply vac is in the positive half cycle (ie ta4<t<ta7). Q4 is turned on in the positive half cycle of the AC power supply vac and cut off in the negative half cycle, and Q3 is turned off in the positive half cycle of the AC power supply vac and turned on in the negative half cycle.

When the peak voltage of vac < set voltage Vi1 ( VBE_Qa1 is the base-emitter turn-on voltage of the NPN type BJT transistor Qa1), and the input voltage overvoltage protection function does not take effect. In this case, the NPN type BJT tube Qa1 is always in the cut-off state. Due to the effects of D1, D2 and R3, Q5 is always on. Q1 and Q4 are turned on in the positive half cycle of the single-phase AC power supply vac and cut off in the negative half cycle, Q2 and Q3 are turned off in the positive half cycle of the single-phase AC power supply vac and turned on in the negative half cycle, and the output voltage vo≈|vac|.

When the peak voltage of vac>set voltage Vi1, the input voltage overvoltage protection function takes effect. Due to the energy storage capacity of the capacitor Ca1, in a part of the time period (see the time period ta1<t<ta2, ta3<t<ta4, ta4<t<ta5, ta6<t<ta7 in Figure 5), the NPN type BJT tube Qa1 is in the conduction state. In this part of the time period, due to the function of Qa1, Q5 is cut off, Q1 is cut off due to the cutoff of Q5 in the positive half cycle of the single-phase AC power supply vac, and Q2 is cut off due to the cutoff of Q5 in the negative half cycle of the single-phase AC power supply vac, the output The voltage vo≈0. In another part of the time period (see the time period ta2<t<ta3 and ta5<t<ta6 in Figure 5), the voltage across the capacitor Ca1 drops due to discharge, and the NPN BJT transistor Qa1 returns to the cut-off state. In this part of the time period, due to the effects of D1, D2 and R3, Q5 resumes the conduction state. In the positive half cycle of the single-phase AC power supply vac, Q1 is turned on due to the conduction of Q5, and in the negative half cycle of the single-phase AC power supply vac. Q2 is turned on due to the conduction of Q5, and the output voltage vo>0.

Embodiment 2: Referring to Fig. 1, Fig. 4 and Fig. 6, Embodiment 2 of the present invention has the function of output current limiting protection, which consists of input capacitor Ci, PNP type BJT tube Q1, PNP type BJT tube Q2, and NPN type BJT tube Q3 , NPN type BJT tube Q4, NPN type BJT tube Q5, output capacitor Co, diode D1, diode D2, resistor R1, resistor R2, resistor R3, controlled current source M1. Wherein, the controlled current source M1 is composed of an NPN type BJT transistor Qb1, a diode Db1, a resistor Rb1, a resistor Rb2, and a capacitor Cb1.

As shown in Figure 4, one end of the input capacitor Ci is simultaneously connected to the positive end of the single-phase AC power supply vac, the anode of the diode D1, the emitter of the PNP BJT transistor Q1, and the emitter of the NPN BJT transistor Q3. The collector of Q1 is connected to one end of resistor R2, the collector of PNP type BJT tube Q2, one end of output capacitor Co, one end of load Z1 and the positive end of output voltage vo, and the base of PNP type BJT tube Q1 is connected to PNP type BJT tube Q1 at the same time. The base of the type BJT tube Q2 is connected to one end of the resistor R1, and the emitter of the PNP type BJT tube Q2 is connected to the emitter of the NPN type BJT tube Q4, the anode of the diode D2, the other end of the input capacitor Ci and the single-phase AC power supply vac The negative terminal of the NPN BJT tube Q3 is connected to the emitter of the NPN BJT tube Q5, the collector of the NPN BJT tube Q4, the other end of the output capacitor Co, and the negative terminal of the output voltage vo. The collector of BJT tube Q5 is connected to the other end of resistor R1 at the same time, the base of NPN type BJT tube Q5 is connected to one end of resistor R3 and port a of controlled current source M1 at the same time, and the other end of resistor R3 is connected to the cathode of diode D1 And the cathode of the diode D2 is connected, the base of the NPN type BJT tube Q3 is connected with the other end of the resistor R2 and the base of the NPN type BJT tube Q4, and the other end of the load Z1 is connected with the anode of the diode Db1 and one end of the resistor Rb1 at the same time, The collector of the NPN type BJT tube Qb1 is the port a of the controlled current source M1, and the emitter of the NPN type BJT tube Qb1 is simultaneously connected to the negative end of the output voltage vo, one end of the resistor Rb2, one end of the capacitor Cb1 and the other end of the resistor Rb1 The base of the NPN type BJT transistor Qb1 is connected to the other end of the resistor Rb2, the other end of the capacitor Cb1 and the cathode of the diode Db1 at the same time.

Fig. 6 is the simulation working wave diagram when the capacitance value of the output capacitor Co is small in Embodiment 2 of the present invention, and its steady-state working principle is as follows:

When vac<0, the single-phase AC power supply vac is in the negative half cycle (ie tb1<t<tb4); when vac>0, the single-phase AC power supply vac is in the positive half cycle (ie tb4<t<tb7). Q4 is turned on in the positive half cycle of the single-phase AC power supply vac and cut off in the negative half cycle, and Q3 is turned off in the positive half cycle of the single-phase AC power supply vac and turned on in the negative half cycle of the single-phase AC power supply vac.

When the output current io<set current Io1 ( VBE_Qb1 is the base-emitter conduction voltage of the NPN BJT transistor Qb1, VDF_Db1 is the forward conduction voltage drop of the diode Db1), and the output current limiting protection function does not take effect. In this case (see time periods tb1<t<tb2, tb3<t<tb4, tb4<t<tb5, tb6<t<tb7 in FIG. 6), the NPN type BJT tube Qb1 is in the off state. Due to the effects of D1, D2 and R3, Q5 is turned on, Q1 is turned on due to the conduction of Q5 in the positive half cycle of the single-phase AC power supply vac, and Q2 is turned on due to the conduction of Q5 in the negative half cycle of the single-phase AC power supply vac , the output current io≈|vac|/Z1.

When the output current io rises and exceeds the set current Io1, the output current limiting protection function takes effect. In this case (see time periods tb2<tb3 and tb5<tb6 in FIG. 6 ), the NPN type BJT transistor Qb1 is in the conduction state. Due to the function of Qb1, although Q5 is turned on, it is in a linear amplification state. In the positive half cycle of single-phase AC power supply vac, Q1 is also in a linear amplification state due to the linear amplification state of Q5. In the negative half cycle of single-phase AC power supply vac, Q2 is in a linear amplification state due to Q5. The linear amplification state is also in the linear amplification state, and the output current io is clamped, that is, io≈Io1.

The content described in the embodiments of this specification is only an enumeration of the implementation forms of the inventive concept. The protection scope of the present invention should not be regarded as limited to the specific forms stated in the embodiments. The protection scope of the present invention also extends to the field Equivalent technical means that the skilled person can think of based on the concept of the present invention.

Claims (4)

1. A BJT type single-phase bridge full-control rectifier circuit, characterized in that: the rectifier circuit includes an input capacitor Ci, a PNP type BJT tube Q1, a PNP type BJT tube Q2, an NPN type BJT tube Q3, and an NPN type BJT tube Q4, NPN type BJT tube Q5, output capacitor Co, diode D1, diode D2, resistor R1, resistor R2, resistor R3 and are used to control the base current of NPN type BJT tube Q5 to realize the pairing of PNP type BJT tube Q1 and PNP type The controlled current source M1 that controls the working state of the BJT tube Q2, one end of the input capacitor Ci is simultaneously connected to the positive end of the single-phase AC power supply vac, the anode of the diode D1, the emitter of the PNP type BJT tube Q1 and the terminal of the NPN type BJT tube Q3 The emitter is connected, and the collector of the PNP type BJT tube Q1 is connected to one end of the resistor R2, the collector electrode of the PNP type BJT tube Q2, one end of the output capacitor Co, one end of the load Z1, and the positive end of the output voltage vo. The PNP type BJT The base of the tube Q1 is connected to the base of the PNP type BJT tube Q2 and one end of the resistor R1 at the same time, and the emitter of the PNP type BJT tube Q2 is simultaneously connected to the emitter of the NPN type BJT tube Q4, the anode of the diode D2, and the input capacitor Ci. The other end is connected to the negative end of the single-phase AC power supply vac, and the collector of the NPN BJT tube Q3 is simultaneously connected to the emitter of the NPN BJT tube Q5, the collector of the NPN BJT tube Q4, the other end of the output capacitor Co, and the load Z1 The other end of the NPN type BJT tube Q5 is connected to the negative end of the output voltage vo, the collector of the NPN type BJT tube Q5 is connected to the other end of the resistor R1, the base of the NPN type BJT tube Q5 is connected to one end of the resistor R3 and the port of the controlled current source M1 at the same time a is connected, the other end of the resistor R3 is connected to the cathode of the diode D1 and the cathode of the diode D2 at the same time, and the base of the NPN BJT transistor Q3 is connected to the other end of the resistor R2 and the base of the NPN BJT transistor Q4 at the same time. 2. A BJT type single-phase bridge fully-controlled rectifier circuit as claimed in claim 1, characterized in that: both ends of the resistor R1 are connected in parallel with an accelerating capacitor C1, both ends of the resistor R2 are connected in parallel with an accelerating capacitor C2, and both ends of the resistor R3 are connected in parallel to accelerate Capacitor C3. 3. A BJT type single-phase bridge fully controlled rectifier circuit as claimed in claim 1 or 2, characterized in that: said controlled current source M1 includes NPN type BJT transistor Qa1, resistor Ra1, resistor Ra2, resistor Ra3 and the capacitor Ca1, the collector of the NPN BJT transistor Qa1 is the port a of the controlled current source M1, the emitter of the NPN BJT transistor Qa1 is connected to one end of the resistor Ra3, one end of the capacitor Ca1 and the negative end of the output voltage vo at the same time, The base of the NPN type BJT transistor Qa1 is connected to one end of the resistor Ra2 and the other end of the resistor Ra3 at the same time, the other end of the resistor Ra2 is connected to one end of the resistor Ra1 and the other end of the capacitor Ca1 at the same time, and the other end of the resistor Ra1 is connected to the diode D1. connected to the cathode. 4. A BJT type single-phase bridge fully controlled rectifier circuit as claimed in claim 1 or 2, characterized in that: said controlled current source M1 includes NPN type BJT transistor Qb1, diode Db1, resistor Rb1, resistor Rb2 And capacitor Cb1, one end of load Z1 is connected to the positive end of output voltage vo, the other end of load Z1 is connected to the anode of diode Db1 and one end of resistor Rb1 at the same time, the collector of NPN type BJT tube Qb1 is the controlled current source M1 Port a, the emitter of the NPN BJT tube Qb1 is connected to the negative terminal of the output voltage vo, one terminal of the resistor Rb2, one terminal of the capacitor Cb1 and the other terminal of the resistor Rb1, and the base of the NPN BJT tube Qb1 is connected to the terminal of the resistor Rb2 at the same time. The other end, the other end of the capacitor Cb1 and the cathode of the diode Db1 are connected.