Three-phase single-tube converter and air conditioner

Abstract

The utility model discloses a three-phase single-tube converter and an air conditioner, the three-phase single-tube converter comprises a three-phase rectifier bridge, the three-phase rectifier bridge is provided with three-phase input ends, a normal-phase output end and an inverted-phase output end, the three-phase input ends are used for being connected with corresponding three-phase live wires one by one, the three-phase rectifier bridge is used for carrying out rectification processing on an accessed three-phase power supply, and the normal-phase output end is connected with the inverted-phase output end; outputting a corresponding first direct-current power supply; the first end of the inductor is connected with the positive phase output end of the three-phase rectifier bridge; the normal-phase input end of the voltage processing circuit is connected with the second end of the inductor, the inverted-phase input end of the voltage processing circuit is connected with the inverted-phase output end of the three-phase rectifier bridge, the output end of the voltage processing circuit is used for accessing an external driving signal, and the voltage processing circuit is used for continuously boosting the accessed first direct-current power supply together with the inductor according to the external driving signal. A corresponding second direct-current power supply is output; according to the technical scheme, the cost of the three-phase single-tube converter is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of air conditioners, in particular to a three-phase single-tube converter and an air conditioner. Background Art

[0002] At present, when the air conditioner is in use, it is powered by a three-phase AC power supply in the power grid. However, in actual driving, most of them still use DC power to drive loads such as motors. For this reason, when setting the power module of the air conditioner, an AC-DC converter is usually used to obtain a DC output voltage. However, the existing three-phase single-tube AC-DC converters are mostly composed of multiple inductors and multiple switching devices, which not only increases the space occupied by the converter, but also increases the use cost of the converter. Utility Model Content

[0003] The main purpose of the utility model is to provide a three-phase single-tube converter and an air conditioner, aiming at reducing the cost of the three-phase single-tube converter.

[0004] To achieve the above object, the three-phase single-tube converter proposed in the present invention comprises:

[0005] A three-phase rectifier bridge, having a three-phase input terminal, a positive phase output terminal and a negative phase output terminal, wherein the three-phase input terminals are used to be connected one by one with the corresponding three-phase live wires, and the three-phase rectifier bridge is used to rectify the connected three-phase power supply and output the corresponding first DC power supply;

[0006] an inductor, a first end of which is connected to the positive phase output end of the three-phase rectifier bridge;

[0007] A voltage processing circuit, wherein the non-phase input terminal is connected to the second end of the inductor, the inverting input terminal is connected to the inverting output terminal of the three-phase rectifier bridge, and the output terminal is used to receive an external drive signal. The voltage processing circuit is used to continuously boost the first DC power supply connected thereto together with the inductor according to the external drive signal, and output a corresponding second DC power supply.

[0008] In some embodiments, the voltage processing circuit includes:

[0009] a diode, an anode of which is connected to the second end of the inductor, and a cathode of which is connected to the positive input end of the external load;

[0010] A switch tube, whose input end is connected to the second end of the inductor, whose output end is connected to the inverting output end of the three-phase rectifier bridge, and whose controlled end is used to receive the external drive signal;

[0011] The capacitor is connected in series between the cathode of the diode and the inverting output end of the three-phase rectifier bridge.

[0012] In some embodiments, the three-phase live wire includes a first-phase live wire, a second-phase live wire, and a third-phase live wire, and the three-phase rectifier bridge includes:

[0013] A first diode, a second diode and a third diode, wherein the cathode of the first diode, the cathode of the second diode and the cathode of the third diode are respectively connected to the first end of the inductor, the anode of the first diode is used to connect to the first phase live wire, the anode of the second diode is used to connect to the second phase live wire, and the anode of the third diode is used to connect to the third phase live wire;

[0014] The fourth diode, the fifth diode and the sixth diode, the cathode of the fourth diode is connected to the anode of the first diode, the cathode of the fifth diode is connected to the anode of the second diode, the cathode of the sixth diode is connected to the anode of the third diode, and the cathodes of the fourth diode, the fifth diode and the sixth diode are respectively connected to the output end of the switching tube.

[0015] The utility model also provides an air conditioner, which includes a control loop and the above-mentioned three-phase single-tube converter;

[0016] The control loop has an output end, a reference signal input end and a plurality of sampling ends, the output end is connected to the controlled end of the three-phase single-tube converter, the plurality of sampling ends are respectively connected to the positive phase output end of the three-phase rectifier bridge of the three-phase single-tube converter and the positive phase output end of the voltage processing circuit, so as to respectively sample the first DC voltage and the first DC current of the first DC power supply, and the second DC voltage of the second DC power supply, and the reference signal input end is used to access the reference voltage;

[0017] The control loop is used to perform feedback processing on the second DC voltage according to the reference voltage, and the first DC voltage and current, so as to stabilize the second DC voltage at a preset voltage.

[0018] In some embodiments, the air conditioner comprises:

[0019] A harmonic processing circuit, whose input end is connected to the positive phase output end of the three-phase rectifier bridge, and the harmonic processing circuit is used to perform inversion processing on the higher harmonics carried by the first DC voltage to output a first DC voltage carrying inverted higher harmonics;

[0020] a voltage feedback loop, wherein a first input terminal of the voltage feedback loop is used to access the reference voltage, and a second input terminal of the voltage feedback loop is connected to a positive phase output terminal of the voltage processing circuit, and the voltage feedback loop is used to perform feedback processing on the second DC voltage according to the reference voltage to output a corresponding first control signal;

[0021] a multiplier, wherein a first input terminal is connected to the output terminal of the harmonic processing circuit, and a second input terminal is connected to the output terminal of the voltage feedback loop, wherein the multiplier is used to process the first control signal according to the first DC voltage carrying the anti-phase higher harmonic, and output a corresponding filtered reference current;

[0022] A drive signal output circuit, wherein the first input end is connected to the output end of the multiplier, the second input end is connected to the positive phase output end of the three-phase rectifier bridge, and the output end is connected to the controlled end of the voltage processing circuit. The voltage processing circuit is used to adjust the duty cycle of the output drive signal according to the reference current and the sampled first DC current to stabilize the second DC voltage at a preset voltage.

[0023] In some embodiments, the harmonic processing circuit comprises:

[0024] a reference voltage output circuit, whose input end is connected to the positive phase output end of the three-phase rectifier bridge, and the reference voltage output circuit is used to perform signal processing on the first DC voltage connected within a preset period of time, so as to output a corresponding minimum voltage through its first output end and a corresponding maximum voltage through its second output end;

[0025] a first subtractor, wherein a first input end thereof is connected to a positive phase output end of the three-phase rectifier bridge, and a second input end thereof is connected to a first output end of the reference voltage output circuit, and the first subtractor is used for performing a subtraction process on the first DC voltage and the minimum voltage to output the higher harmonics in the first DC power supply separately;

[0026] an inverter, whose input end is connected to the output end of the first subtractor, and the inverter is used to invert the higher harmonics and output inverted higher harmonics;

[0027] An adder, whose first input terminal is connected to the output terminal of the inverter, and whose second input terminal is connected to the second output terminal of the reference voltage output circuit, wherein the adder is used to add the inverted higher harmonics to the maximum voltage and output a first DC voltage carrying the inverted higher harmonics.

[0028] In some embodiments, the reference voltage output circuit includes:

[0029] A filter, whose input end is connected to the positive phase output end of the three-phase rectifier bridge, and the filter is used to filter the sampled first DC voltage and then output it;

[0030] an analog-to-digital converter, whose input end is connected to the output end of the filter, and the analog-to-digital converter is used to perform analog-to-digital conversion on the first DC voltage and output a corresponding DC digital voltage;

[0031] A processor, whose input end is connected to the output end of the analog-to-digital converter, whose first output end is connected to the second input end of the subtractor, and whose second output end is connected to the second input end of the adder, wherein the processor is used to perform signal processing on the DC digital voltage within a preset sampling period to output a corresponding minimum voltage to the first subtractor and a maximum voltage to the adder.

[0032] In some embodiments, the voltage feedback loop includes:

[0033] a second subtractor, wherein a first input terminal of the second subtractor is used to access a reference voltage, and a second input terminal of the second subtractor is used to access a sampled second DC voltage, and the second subtractor is used to perform a subtraction process on the reference voltage and the second DC voltage, and output a corresponding first voltage difference;

[0034] A first PI controller is connected in series between the output end of the second subtractor and the first input end of the multiplier, and the first PI controller is used to perform feedback processing on the second DC voltage according to the first voltage difference to output the corresponding first control signal to the multiplier.

[0035] In some embodiments, the driving signal output circuit includes:

[0036] a current feedback loop, wherein a first input end of the current feedback loop is connected to the output end of the multiplier, and a second input end of the current feedback loop is used to receive the sampled first DC current, and the current feedback loop is used to perform feedback processing on the first DC current according to the reference current and output a corresponding first DC current;

[0037] A drive signal generating circuit, whose input end is connected to the output end of the current feedback loop, and whose output end is used to access the controlled end of the three-phase single-tube converter, and the drive signal generating circuit is used to adjust the duty cycle of the output drive signal according to the first direct current received.

[0038] In some embodiments, the current feedback loop includes:

[0039] a third subtractor, wherein a first input terminal of the third subtractor is connected to the input terminal of the multiplier, and a second input terminal of the third subtractor is used to receive the sampled first DC current, and the third subtractor is used to perform a subtraction process on the reference current and the first DC current, and output a corresponding current difference;

[0040] A second PI controller is connected in series between the output end of the third subtractor and the input end of the drive signal generating circuit, and the second PI controller is used to perform feedback processing on the first DC current according to the current difference to output the first DC current to the drive signal generating circuit.

[0041] The technical solution of the utility model reduces the number of inductors to one by connecting an inductor in series between the three-phase rectifier bridge and the voltage processing circuit, and continuously boosts the first DC power supply output by the three-phase rectifier bridge through the inductor and the voltage processing circuit, thereby compensating for the reduction in boosting capacity caused by insufficient freewheeling capacity after the number of inductors is reduced, and ensuring that the boosting capacity of the converter is not greatly affected after the inductance is reduced, thereby achieving the reduction in cost of the three-phase single-tube converter while enabling it to work normally. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0043] Figure 1 It is a structural schematic diagram of an embodiment of a three-phase single-tube converter of the utility model;

[0044] Figure 2 It is a structural schematic diagram of another embodiment of the three-phase single-tube converter of the utility model;

[0045] Figure 3 It is a structural schematic diagram of an existing three-phase single-tube converter;

[0046] Figure 4 It is a structural schematic diagram of an embodiment of a control loop in the utility model;

[0047] Figure 5 It is a structural schematic diagram of an embodiment of a harmonic processing circuit in the utility model;

[0048] Figure 6 It is a structural schematic diagram of another embodiment of the harmonic processing circuit in the utility model;

[0049] Figure 7 It is a structural schematic diagram of an embodiment of a voltage feedback loop in the utility model;

[0050] Figure 8 It is a structural schematic diagram of an embodiment of a driving signal output circuit in the utility model;

[0051] Fig. 9 It is a structural schematic diagram of another embodiment of the driving signal output circuit in the utility model;

[0052] Fig.10 The figure is a waveform diagram of the utility model for processing high-order harmonics.

[0053] Description of Figure Numbers:

[0054] Label name Label name 100 Three-phase rectifier bridge 420 First PI controller 200 Voltage Processing Circuit 500 Multiplier 300 Harmonic Processing Circuit 600 Drive signal output circuit 310 Reference voltage output circuit 610 Current Feedback Loop 311 filter 611 The third subtractor 312 Analog-to-digital converter 612 Second PI controller 313 processor 620 Driving signal generating circuit 320 First subtractor Lx inductance 330 Inverter Dx diode 340 Adder Q1 Switching tube 400 Voltage Feedback Loop D1~D6 The first diode to the sixth diode 410 Second subtractor C1 capacitance

[0055] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0056] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0057] In addition, in the present utility model, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0058] The utility model provides a three-phase single-tube converter.

[0059] Reference Figure 1 In one embodiment, the three-phase single-tube converter comprises:

[0060] The three-phase rectifier bridge 100 has a three-phase input terminal, a positive phase output terminal and a negative phase output terminal, wherein the three-phase input terminals are used to be connected to the corresponding three-phase live wires one by one, and the three-phase rectifier bridge 100 is used to rectify the connected three-phase power supply and output the corresponding first DC power supply;

[0061] An inductor Lx, a first end of which is connected to the positive phase output end of the three-phase rectifier bridge 100;

[0062] The voltage processing circuit 200 has a positive input terminal connected to the second end of the inductor Lx, an inverting input terminal connected to the inverting output terminal of the three-phase rectifier bridge 100, and an output terminal for receiving an external drive signal. The voltage processing circuit 200 is used to continuously boost the first DC power supply connected thereto together with the inductor Lx according to the external drive signal, and output a corresponding second DC power supply.

[0063] It should be noted that if Figure 3 As shown, the existing three-phase single-tube converter usually adopts discontinuous mode boosting, and in order to achieve the boosting effect, a boost inductor Lx is connected in series at each input end. Since the price of the boost inductor Lx is usually relatively expensive, this increases the cost of the three-phase single-tube converter when designing. Therefore, in this embodiment, the three inductors Lx originally connected in series at the input end are removed, and an inductor Lx is connected in series between the three-phase rectifier bridge 100 and the voltage processing circuit 200, so that the number of inductors Lx is reduced. Since the number of inductors Lx is reduced, the freewheeling capability of the converter topology will be reduced, and for the converter topology, the freewheeling capability of the inductor Lx determines its maximum boosting capability. Therefore, in order to make up for the deficiency of the boosting capability caused by the insufficient freewheeling capability after the number of inductors Lx is reduced, this embodiment also sets the three-phase single-tube converter after the inductor Lx is reduced to continuous mode boosting, to ensure that the boosting capability of the converter after the inductor Lx is reduced will not be greatly affected, so as to reduce the cost of the three-phase single-tube converter while enabling it to work normally.

[0064] When the three-phase single-tube converter is working, each input end of the three-phase rectifier bridge 100 is used to connect a phase of AC power supply, and the connected three-phase AC power supply is rectified by the three-phase rectifier bridge 100 to output the corresponding first DC power supply to the inductor Lx, and the inductor Lx and the voltage processing circuit 200 jointly boost the first DC power supply.

[0065] Specifically, when the voltage processing circuit 200 directly connects the inductor Lx to the inverting output terminal of the three-phase rectifier bridge 100 according to the received driving signal, the second end of the inductor Lx is short-circuited to the ground, and the first DC power supply output by the three-phase rectifier bridge 100 flows to charge the inductor Lx. At this time, the voltage direction across the inductor Lx is opposite to the direction of the first DC voltage.

[0066] When the voltage processing circuit 200 disconnects the inductor Lx from the inverting output terminal of the three-phase rectifier bridge 100 according to the received driving signal, and the first DC power supply supplies power to the load, since the current flowing through the inductor Lx cannot change suddenly, the inductor Lx starts to discharge to the load, so that the voltage across the load is the sum of the inductor Lx voltage and the first DC voltage. At the same time, since an energy storage device is provided in the voltage processing circuit 200, the first DC power supply and the inductor Lx charge the voltage processing circuit 200 when supplying power to the load, wherein the electric energy stored in the voltage processing circuit 200 will supply power to the load in the next cycle when the first DC power supply charges the inductor Lx, so as to maintain the load power-on operation, thereby realizing the boost processing of the first DC power supply and outputting the boosted second DC power supply.

[0067] It should be noted that, since the converter topology composed of the three-phase rectifier bridge 100, the inductor Lx and the voltage processing circuit 200 adopts continuous mode boost, when the inductor Lx and the voltage processing circuit 200 jointly process the first DC power supply, the current value of the output second DC power supply will not drop to zero when the inductor Lx is charged, and the current in the inductor Lx always exists and can continuously transfer energy, thereby improving the boost capability of the converter topology.

[0068] The technical solution of the utility model reduces the number of inductors Lx to one by connecting an inductor Lx in series between the three-phase rectifier bridge 100 and the voltage processing circuit 200. The first DC power supply output by the three-phase rectifier bridge 100 is continuously boosted by the inductor Lx and the voltage processing circuit 200, thereby compensating for the reduction in boosting capability caused by insufficient freewheeling capability after the number of inductors Lx is reduced, and ensuring that the boosting capability of the converter is not greatly affected after the inductor Lx is reduced, thereby reducing the cost of the three-phase single-tube converter and enabling it to work normally.

[0069] Reference Figure 1 to Figure 2 In one embodiment, the voltage processing circuit includes:

[0070] a diode Dx, an anode of which is connected to the second end of the inductor Lx, and a cathode of which is connected to the positive input end of the external load;

[0071] A switch tube Q1, whose input end is connected to the second end of the inductor Lx, whose output end is connected to the inverting output end of the three-phase rectifier bridge 100, and whose controlled end is used to receive the external driving signal;

[0072] The capacitor C1 is connected in series between the cathode of the diode Dx and the inverting output terminal of the three-phase rectifier bridge 100 .

[0073] In this embodiment, the level of the driving signal driving the switch tube Q1 to be turned on or off is related to the model of the switch tube Q1. Specifically, the switch tube Q1 is turned on when driven at a high level and is turned off when driven at a low level as an example for explanation:

[0074] When the switch tube Q1 receives a high level and directly connects the inductor Lx to the inverting output terminal of the three-phase rectifier bridge 100, the second end of the inductor Lx is short-circuited to the ground, and the load is powered by the electric energy stored in the capacitor C1 when it is charged in the previous cycle. Due to the presence of the diode Dx, the electric energy stored in the capacitor C1 can only be output to the load in one direction and will not flow back to the switch tube Q1. At the same time, the first DC power supply output by the three-phase rectifier bridge 100 flows to charge the inductor Lx. At this time, the voltage direction across the inductor Lx is opposite to the direction of the first DC voltage.

[0075] When the switch tube Q1 receives a low level and disconnects the inductor Lx from the inverting output terminal of the three-phase rectifier bridge 100, the first DC power supply supplies power to the load and charges the capacitor C1 at the same time. Since the current flowing through the inductor Lx cannot change suddenly, the inductor Lx starts to discharge to the load, so that the voltage across the load is the sum of the inductor Lx voltage and the first DC voltage, thereby achieving a boost processing of the first DC power supply and outputting a boosted second DC power supply.

[0076] Reference Figure 1 to Figure 2 In one embodiment, the three-phase live wire includes a first-phase live wire, a second-phase live wire and a third-phase live wire, and the three-phase rectifier bridge 100 includes:

[0077] The cathode of the rectifier tube and the cathode of the third rectifier tube are respectively connected to the first end of the inductor Lx, the anode of the first rectifier tube is used to connect to the first phase live wire, the anode of the second rectifier tube is used to connect to the second phase live wire, and the anode of the third rectifier tube is used to connect to the third phase live wire;

[0078] The fourth rectifier, the fifth rectifier and the sixth rectifier, the cathode of the fourth rectifier is connected to the anode of the first rectifier, the cathode of the fifth rectifier is connected to the anode of the second rectifier, the cathode of the sixth rectifier is connected to the anode of the third rectifier, and the cathode of the fourth rectifier, the cathode of the fifth rectifier and the cathode of the sixth rectifier are respectively connected to the output end of the switch tube Q1.

[0079] In this embodiment, D1, D2, and D3 are rectifier tubes of a common anode group, and D4, D5, and D6 are rectifier tubes of a common cathode group.

[0080] Since the AC power source connected to the three-phase rectifier bridge 100 is three-phase electricity, the phases of the first phase power source, the second phase power source, and the third phase power source are 0°, 120°, and 240°, respectively. When the three-phase rectifier bridge 100 is working, the three-phase rectifier bridge 100 must have two rectifiers turned on at the same time at any time to form a load current, one of which is in the common anode group and the other is in the common cathode group. Each of the six thyristors is turned on for 120°, and a rectifier is commutated every 60°, that is, when the three-phase AC power source is connected, D1 and D5, D1 and D6, D2 and D6, D2 and D4, D3 and D4, D3 and D5 are controlled to be turned on in sequence, and the conduction time of multiple pairs of rectifiers is the same. Thereby, the phase voltage between each two-phase power source is rectified respectively, and the corresponding first DC power source is output.

[0081] Reference Figure 1 , in one embodiment, the air conditioner comprises a control loop and the above-mentioned three-phase single-tube converter;

[0082] The control loop has an output end, a reference signal input end and a plurality of sampling ends, wherein the output end is connected to the controlled end of the three-phase single-tube converter, and the plurality of sampling ends are respectively connected to the positive phase output end of the three-phase rectifier bridge 100 of the three-phase single-tube converter and the positive phase output end of the voltage processing circuit 200, so as to respectively sample the first DC voltage and the first DC current of the first DC power supply, and the second DC voltage of the second DC power supply, and the reference signal input end is used to access the reference voltage;

[0083] The control loop is used to perform feedback processing on the second DC voltage according to the reference voltage, the first DC voltage and the first DC current, so as to stabilize the second DC voltage at a preset voltage.

[0084] In this embodiment, the preset voltage is pre-set in the memory of the three-phase single-switch converter and is set by the designer when designing the converter.

[0085] The control loop is used to adjust the output voltage of the three-phase single-tube converter. Specifically, after the three-phase rectifier bridge 100 of the converter outputs the rectified first DC power supply, it is necessary to perform continuous boost processing under the joint action of the inductor Lx and the voltage processing circuit 200 to output the second DC power supply, wherein the second DC voltage is related to the proportion of the charging time and the freewheeling time of the inductor Lx in one cycle. In order to make the second DC voltage meet the preset voltage, the control loop needs to collect the second DC voltage output by the converter, as well as the rectified first DC voltage and current, perform feedback processing on the second DC voltage, and adjust the duty cycle of the switch tube Q1 of the voltage processing circuit 200 when it is turned on and off, so as to adjust the second DC voltage and stabilize it near the preset voltage.

[0086] Reference Figures 1 to 4 In one embodiment, the air conditioner comprises:

[0087] A harmonic processing circuit 300, whose input end is connected to the positive phase output end of the three-phase rectifier bridge 100, and the harmonic processing circuit 300 is used to perform inversion processing on the higher harmonics carried by the first DC voltage to output a first DC voltage carrying inverted higher harmonics;

[0088] A voltage feedback loop 400, wherein a first input terminal thereof is used to access the reference voltage, and a second input terminal thereof is connected to a non-inverting output terminal of the voltage processing circuit 200, and the voltage feedback loop 400 is used to output a corresponding first control signal according to a deviation between the reference voltage and the second DC voltage;

[0089] a multiplier 500, wherein a first input terminal is connected to the output terminal of the harmonic processing circuit 300, and a second input terminal is connected to the output terminal of the voltage feedback loop 400, and the multiplier 500 is used to output a corresponding reference current according to the first DC voltage carrying the anti-phase higher harmonic and the first control signal;

[0090] The drive signal output circuit 600 has a first input end connected to the output end of the multiplier 500, a second input end connected to the positive phase output end of the three-phase rectifier bridge 100, and an output end connected to the controlled end of the voltage processing circuit. The drive signal output circuit 600 is used to adjust the duty cycle of the output drive signal according to the reference current and the sampled first DC current to stabilize the second DC voltage at a preset voltage.

[0091] In this embodiment, when the converter is working, the voltage feedback loop 400 collects the second DC voltage of the converter in real time, and outputs a corresponding first control signal by calculating the deviation between the second DC voltage and the preset voltage, wherein the first control signal represents the adjustment amount of the switch tube Q1 being turned on and off. At the same time, the harmonic processing circuit 300 is used to collect the higher harmonics carried by the first DC voltage, and invert the collected higher harmonics to output the corresponding first DC voltage carrying the inverted higher harmonics, so that when the multiplier 500 calculates the corresponding reference current according to the first control signal, the interference of the higher harmonics in the first DC power supply can be reduced according to the first DC voltage carrying the inverted higher harmonics, so that the multiplier 500 can convert the first control signal into the corresponding reference current according to the first DC voltage of the inverted higher harmonics, and further perform feedback adjustment on the first DC current through the drive signal output circuit 600, and adjust the duty cycle of the output drive signal according to the sampled first DC current, so as to stabilize the second DC voltage at the preset voltage.

[0092] Reference Figure 1 , Figure 2 and Figure 5 In one embodiment, the harmonic processing circuit 300 includes:

[0093] A reference voltage output circuit 310, whose input end is connected to the positive phase output end of the three-phase rectifier bridge 100, and the reference voltage output circuit 310 is used to perform signal processing on the first DC voltage connected within a preset period of time, so as to output a corresponding minimum voltage through its first output end and a corresponding maximum voltage through its second output end;

[0094] A first subtractor 320, a first input end of which is connected to the positive phase output end of the three-phase rectifier bridge 100, and a second input end of which is connected to the first output end of the reference voltage output circuit 310, and the first subtractor 320 is used to perform a subtraction process on the first DC voltage and the minimum voltage to output the higher harmonics in the first DC power supply separately;

[0095] An inverter 330, whose input end is connected to the output end of the first subtractor 320, and the inverter 330 is used to invert the higher harmonics and output inverted higher harmonics;

[0096] The adder 340 has a first input terminal connected to the output terminal of the inverter 330, and a second input terminal connected to the second output terminal of the reference voltage output circuit 310. The adder 340 is used to add the inverted higher harmonics to the maximum voltage and output a first DC voltage carrying the inverted higher harmonics.

[0097] In this embodiment, when processing the harmonics carried by the first DC power supply, the reference voltage output circuit 310 first filters the collected first DC voltage to avoid interfering with the minimum voltage and maximum voltage of the sampled first DC voltage.

[0098] After filtering, the reference voltage output circuit 310 outputs the minimum voltage sampled within the preset sampling time to the first subtractor 320, and outputs the maximum voltage to the maximum adder 340, wherein the preset sampling time is set by the R&D personnel when designing the control loop according to the sampling accuracy required by the control loop. The first subtractor 320 removes the reference potential of the first DC voltage of the high-order harmonics, and outputs the high-order harmonics with 0 voltage as the reference potential, so that the high-order harmonics are inverted into inverted high-order harmonics after passing through the inverter 330, so that the inverted high-order harmonics are input into the first adder 340 together with the maximum voltage for addition processing, and the output is the corresponding first DC voltage carrying the inverted high-order harmonics.

[0099] It should be noted that if Fig.10 As shown, only when the minimum voltage is subtracted from the first DC voltage carrying the higher harmonics, the trough of the higher harmonics will fall at 0 voltage, otherwise the trough of the higher harmonics will be a negative voltage, and the higher harmonics will not be higher harmonics with 0 voltage as the reference potential. For the first adder 340, if the minimum voltage is added to the inverted higher harmonics instead of the maximum voltage, the reference potential of the inverted higher harmonics will be smaller than the theoretical value, therefore, when performing subtraction processing on the first DC voltage carrying the higher harmonics, the minimum voltage needs to be subtracted, and when performing addition processing on the inverted higher harmonics, the maximum voltage needs to be added.

[0100] Reference Figure 1 , Figure 2 and Figure 6 In one embodiment, the reference voltage output circuit 310 includes:

[0101] A filter 311, whose input end is connected to the positive phase output end of the three-phase rectifier bridge 100, and the filter 311 is used to filter the sampled first DC voltage and then output it;

[0102] an analog-to-digital converter 312, whose input end is connected to the output end of the filter 311, and the analog-to-digital converter 312 is used to perform analog-to-digital conversion on the first DC voltage and output a corresponding DC digital voltage;

[0103] A processor 313, whose input end is connected to the output end of the analog-to-digital converter 312, whose first output end is connected to the second input end of the subtractor, and whose second output end is connected to the second input end of the adder 340. The processor 313 is used to perform signal processing on the DC digital voltage within a preset sampling period to output the corresponding minimum voltage to the first subtractor and output the maximum voltage to the adder 340.

[0104] In this embodiment, when processing the harmonics carried by the first DC power supply, the filter 311 first performs filtering processing on the collected first DC voltage, and outputs the filtered first DC voltage to the analog-to-digital converter 312, so that the first DC voltage is converted into a DC digital voltage that can be recognized by the processor 313. After receiving the DC numerical voltage, the processor 313 outputs its average value as the minimum voltage according to the minimum value of the first DC voltage in each cycle within the preset sampling period, and outputs its average value as the maximum voltage according to the maximum value of the first DC voltage in each cycle within the preset sampling period.

[0105] Reference Figure 1 , Figure 2 and Figure 7 In one embodiment, the voltage feedback loop 400 includes:

[0106] A second subtractor 410, wherein a first input terminal thereof is used to access a reference voltage, and a second input terminal thereof is used to access a sampled second DC voltage, and the second subtractor 410 is used to perform a subtraction process on the reference voltage and the second DC voltage, and output a corresponding first voltage difference;

[0107] The first PI controller 420 is connected in series between the output end of the second subtractor 410 and the first input end of the multiplier 500. The first PI controller 420 is used to perform feedback processing on the second DC voltage according to the first voltage difference to output the corresponding first control signal to the multiplier 500.

[0108] In this embodiment, when the voltage feedback loop 400 collects the second DC voltage of the converter, the second subtractor 410 performs subtraction processing on the collected second DC voltage and the connected preset voltage, and outputs a first voltage difference value representing the deviation between the second DC voltage and the preset voltage. The first PI controller 420 performs PI processing based on the connected first voltage difference value, and outputs a first control signal representing the adjustment amount of the switch tube Q1 being turned on and off.

[0109] Reference Figure 1 , Figure 2 and Figure 8In one embodiment, the driving signal output circuit 600 includes:

[0110] A current feedback loop 610, wherein a first input terminal is connected to the output terminal of the multiplier 500, and a second input terminal is used to receive the sampled first DC current, and the current feedback loop 610 is used to output a corresponding second control signal according to a deviation between the reference current and the first DC current;

[0111] The drive signal generating circuit 620 has an input end connected to the output end of the current feedback loop 610, and an output end used to access the controlled end of the three-phase single-tube converter. The drive signal generating circuit 620 is used to adjust the duty cycle of the output drive signal according to the received second control signal.

[0112] In this embodiment, the driving signal generating circuit 620 may be a PWM generator, or a PWM module inside a DSP (Digital Signal Process) chip.

[0113] After the current feedback loop 610 receives the reference current output by the multiplier 500, the current feedback loop 610 makes a difference between the first DC current of the converter acquired in real time and the reference current, and outputs a corresponding second control signal according to the deviation between the second DC voltage and the preset voltage, so that the drive signal transmitting circuit outputs a drive signal with a corresponding duty cycle according to the acquired second control signal. The second control signal represents the adjustment amount of the ratio of the switch tube Q1 to be turned on and off when processing the first DC current.

[0114] Reference Figure 1 , Figure 2 and Fig. 9 In one embodiment, the current feedback loop 610 includes:

[0115] A third subtractor 611, whose first input terminal is connected to the input terminal of the multiplier 500, and whose second input terminal is used to access the sampled first DC current, and the third subtractor 611 is used to perform subtraction processing on the reference current and the first DC current, and output a corresponding current difference;

[0116] The second PI controller 612 is connected in series between the output end of the third subtractor 611 and the input end of the drive signal generating circuit 620. The second PI controller 612 is used to perform feedback processing on the first DC current according to the current difference to output the second control signal to the drive signal generating circuit 620.

[0117] In this embodiment, when the voltage feedback loop 400 collects the second DC voltage of the converter, the second subtractor 410 performs subtraction processing on the collected second DC voltage and the connected preset voltage, and outputs a first voltage difference value representing the deviation between the second DC voltage and the preset voltage. The first PI controller 420 performs PI processing based on the connected first voltage difference value, and outputs a first control signal representing the adjustment amount of the switch tube Q1 being turned on and off.

[0118] The above description is only an optional embodiment of the utility model, and does not limit the patent scope of the utility model. All equivalent structural changes made by using the contents of the utility model specification and drawings under the utility model concept, or directly / indirectly used in other related technical fields are included in the patent protection scope of the utility model.

Claims

1. A three-phase single-tube converter, characterized in that: include: A three-phase rectifier bridge, having a three-phase input terminal, a positive phase output terminal and a negative phase output terminal, wherein the three-phase input terminals are used to be connected one by one with the corresponding three-phase live wires, and the three-phase rectifier bridge is used to rectify the connected three-phase power supply and output the corresponding first DC power supply; an inductor, a first end of which is connected to the positive phase output end of the three-phase rectifier bridge; A voltage processing circuit, wherein the non-phase input terminal is connected to the second end of the inductor, the inverting input terminal is connected to the inverting output terminal of the three-phase rectifier bridge, and the output terminal is used to receive an external drive signal. The voltage processing circuit is used to continuously boost the first DC power supply connected thereto together with the inductor according to the external drive signal, and output a corresponding second DC power supply.

2. The three-phase single-tube converter according to claim 1, characterized in that: The voltage processing circuit comprises: a diode, an anode of which is connected to the second end of the inductor, and a cathode of which is connected to the positive input end of the external load; A switch tube, whose input end is connected to the second end of the inductor, whose output end is connected to the inverting output end of the three-phase rectifier bridge, and whose controlled end is used to receive the external drive signal; The capacitor is connected in series between the cathode of the diode and the inverting output end of the three-phase rectifier bridge.

3. The three-phase single-tube converter according to claim 1, characterized in that: The three-phase live wire includes a first-phase live wire, a second-phase live wire and a third-phase live wire, and the three-phase rectifier bridge includes: A first rectifier, a second rectifier and a third rectifier, wherein the cathode of the first rectifier, the cathode of the second rectifier and the cathode of the third rectifier are respectively connected to the first end of the inductor, the anode of the first rectifier is used to connect to the first phase live wire, the anode of the second rectifier is used to connect to the second phase live wire, and the anode of the third rectifier is used to connect to the third phase live wire; A fourth rectifier, a fifth rectifier and a sixth rectifier, wherein the cathode of the fourth rectifier is connected to the anode of the first rectifier, the cathode of the fifth rectifier is connected to the anode of the second rectifier, the cathode of the sixth rectifier is connected to the anode of the third rectifier, and the cathodes of the fourth rectifier, the fifth rectifier and the sixth rectifier are respectively connected to the inverting input terminal of the voltage processing circuit.

4. An air conditioner, characterized in that: The air conditioner comprises a control loop and a three-phase single-tube converter as claimed in any one of claims 1 to 3; The control loop has an output end, a reference signal input end and a plurality of sampling ends, the output end is connected to the controlled end of the three-phase single-tube converter, the plurality of sampling ends are respectively connected to the positive phase output end of the three-phase rectifier bridge of the three-phase single-tube converter and the positive phase output end of the voltage processing circuit, so as to respectively sample the first DC voltage and the first DC current of the first DC power supply, and the second DC voltage of the second DC power supply, and the reference signal input end is used to access the reference voltage; The control loop is used to perform feedback processing on the second DC voltage according to the reference voltage, the first DC voltage and the first DC current, so as to stabilize the second DC voltage at a preset voltage.

5. The air conditioner according to claim 4, characterized in that: The air conditioner comprises: A harmonic processing circuit, whose input end is connected to the positive phase output end of the three-phase rectifier bridge, and the harmonic processing circuit is used to perform inversion processing on the higher harmonics carried by the first DC voltage to output a first DC voltage carrying inverted higher harmonics; a voltage feedback loop, wherein a first input terminal of the voltage feedback loop is used to access the reference voltage, and a second input terminal of the voltage feedback loop is connected to a positive phase output terminal of the voltage processing circuit, and the voltage feedback loop is used to output a corresponding first control signal according to a deviation between the reference voltage and the second DC voltage; a multiplier, wherein a first input terminal is connected to the output terminal of the harmonic processing circuit, and a second input terminal is connected to the output terminal of the voltage feedback loop, and the multiplier is used to output a corresponding reference current according to the first DC voltage carrying the inverted higher-order harmonic and the first control signal; A drive signal output circuit, wherein the first input end is connected to the output end of the multiplier, the second input end is connected to the positive phase output end of the three-phase rectifier bridge, and the output end is connected to the controlled end of the voltage processing circuit. The drive signal output circuit is used to adjust the duty cycle of the output drive signal according to the reference current and the sampled first DC current to stabilize the second DC voltage at a preset voltage.

6. The air conditioner according to claim 5, characterized in that: The harmonic processing circuit comprises: a reference voltage output circuit, whose input end is connected to the positive phase output end of the three-phase rectifier bridge, and the reference voltage output circuit is used to perform signal processing on the first DC voltage connected within a preset period of time, so as to output a corresponding minimum voltage through its first output end and a corresponding maximum voltage through its second output end; a first subtractor, wherein a first input end thereof is connected to a positive phase output end of the three-phase rectifier bridge, and a second input end thereof is connected to a first output end of the reference voltage output circuit, and the first subtractor is used for performing a subtraction process on the first DC voltage and the minimum voltage to output the higher harmonics separately; an inverter, whose input end is connected to the output end of the first subtractor, and the inverter is used to invert the higher harmonics and output inverted higher harmonics; An adder, whose first input terminal is connected to the output terminal of the inverter, and whose second input terminal is connected to the second output terminal of the reference voltage output circuit, wherein the adder is used to add the inverted higher harmonics to the maximum voltage and output a first DC voltage carrying the inverted higher harmonics.

7. The air conditioner according to claim 6, characterized in that: The reference voltage output circuit comprises: A filter, whose input end is connected to the positive phase output end of the three-phase rectifier bridge, and the filter is used to filter the sampled first DC voltage and then output it; an analog-to-digital converter, whose input end is connected to the output end of the filter, and the analog-to-digital converter is used to perform analog-to-digital conversion on the first DC voltage and output a corresponding DC digital voltage; A processor, whose input end is connected to the output end of the analog-to-digital converter, whose first output end is connected to the second input end of the subtractor, and whose second output end is connected to the second input end of the adder, wherein the processor is used to perform signal processing on the DC digital voltage within a preset sampling period to output a corresponding minimum voltage to the first subtractor and a maximum voltage to the adder.

8. The air conditioner according to claim 5, characterized in that: The voltage feedback loop includes: a second subtractor, wherein a first input terminal of the second subtractor is used to access a reference voltage, and a second input terminal of the second subtractor is used to access a sampled second DC voltage, and the second subtractor is used to perform a subtraction process on the reference voltage and the second DC voltage, and output a corresponding first voltage difference; A first PI controller is connected in series between the output end of the second subtractor and the first input end of the multiplier, and the first PI controller is used to perform feedback processing on the second DC voltage according to the first voltage difference to output the corresponding first control signal to the multiplier.

9. The air conditioner according to claim 5, characterized in that: The driving signal output circuit comprises: a current feedback loop, wherein a first input end of the current feedback loop is connected to the output end of the multiplier, and a second input end of the current feedback loop is used to receive the sampled first DC current, and the current feedback loop is used to output a corresponding second control signal according to a deviation between the reference current and the first DC current; A drive signal generating circuit, whose input end is connected to the output end of the current feedback loop, and whose output end is used to access the controlled end of the three-phase single-tube converter, and the drive signal generating circuit is used to adjust the duty cycle of the output drive signal according to the received second control signal.

10. The air conditioner according to claim 9, characterized in that: The current feedback loop includes: a third subtractor, wherein a first input terminal of the third subtractor is connected to the input terminal of the multiplier, and a second input terminal of the third subtractor is used to receive the sampled first DC current, and the third subtractor is used to perform a subtraction process on the reference current and the first DC current, and output a corresponding current difference; A second PI controller is connected in series between the output end of the third subtractor and the input end of the drive signal generating circuit, and the second PI controller is used to perform feedback processing on the first DC current according to the current difference to output the second control signal to the drive signal generating circuit.

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