Driving protection circuit and electric equipment

Abstract

The utility model discloses a driving protection circuit and electric equipment, the driving protection circuit comprises a rectifier bridge connected with AC input, and the output end of the rectifier bridge is connected with a first bus capacitor and a second bus capacitor in sequence; the rear stage of the first bus capacitor is connected with a first load circuit, the rear stage of the second bus capacitor is connected with a second load circuit, and a current direction limiting unit is connected in series on a direct current bus connecting the first bus capacitor and the second bus capacitor; the current direction limiting unit can adjust the second bus capacitor to conduct or cut off a power supply path of the first bus capacitor. Compared with the prior art, the current direction limiting unit is additionally arranged, so that the risk of operational reliability in the integrated control process of the three-phase fan and the three-phase compressor under the condition of no electrolytic capacitor can be solved.

Description

TECHNICAL FIELD

[0001] The utility model relates to drive circuit, especially a kind of drive protection circuit and electrical equipment. BACKGROUND

[0002] At present, domestic, commercial air conditioning products are being implemented in large area frequency conversion, and the reliability of frequency conversion driving technology is more and more concerned. In order to improve the service life of the driving board, electrolytic capacitor-free driving technology has become the preferred technical solution.

[0003] Because the capacity density of the thin film capacitor is low, using the thin film capacitor instead of the electrolytic capacitor will greatly reduce the bus energy storage capacity of the frequency conversion driving board, which will cause the bus power supply voltage to fluctuate greatly.

[0004] In the air conditioning system, the outdoor unit fan and the compressor are generally frequency conversion, which requires the fan and compressor frequency converter to control the frequency of the corresponding motor. In the integrated frequency conversion driving scheme, the fan and compressor frequency converter share the DC bus. Combined with the characteristics of the electrolytic capacitor-free driving scheme, the bus voltage fluctuation will not only affect the compressor control, but also affect the fan control.

[0005] The above problems mainly manifest when the fan operates at a noise frequency. Due to the noise problem caused by the mutual influence of fan bus fluctuation and inherent frequency.

[0006] Therefore, how to solve the mutual influence problem between the compressor and the fan in the integrated driving circuit of the compressor and the fan is a technical problem to be solved in the industry. INVENTION CONTENTS

[0007] In view of the mutual influence problem between the compressor and the fan in the integrated driving circuit of the compressor and the fan in the prior art, the utility model provides a kind of drive protection circuit and electrical equipment.

[0008] The technical scheme of the utility model provides a kind of drive protection circuit, including the rectifier bridge connected with AC input, the output of the rectifier bridge is connected with first bus capacitor and second bus capacitor in turn;

[0009] The first bus capacitor is connected with the first load circuit in back stage, and the second bus capacitor is connected with the second load circuit in back stage, and the current limiting unit is connected in series on the DC bus connecting the first bus capacitor and the second bus capacitor;

[0010] The current limiting unit can adjust the second bus capacitor to be the power supply path of the first bus capacitor to be turned on or cut off.

[0011] Further, the current limiting unit comprises a power diode connected in series between the first bus capacitor and the second bus capacitor, and an insulated gate bipolar transistor connected in parallel with the power diode;

[0012] The positive electrode of the power diode is connected to the first bus capacitor, and the negative electrode of the power diode is connected to the second bus capacitor.

[0013] The control end of the insulated gate bipolar transistor is connected with a driving chip, and the driving chip is used for controlling the insulated gate bipolar transistor to be turned on or turned off.

[0014] Further, the alternating current input adopts a three-phase alternating current power supply, and the rectifier bridge adopts a three-phase full-bridge circuit.

[0015] The three-phase full-bridge circuit has a first bridge arm composed of diode D1 and diode D2, a second bridge arm composed of diode D3 and diode D4, and a third bridge arm composed of diode D5 and diode D6.

[0016] The three-phase outputs of the three-phase alternating current power supply are respectively connected to the midpoints of the first bridge arm, the second bridge arm and the third bridge arm.

[0017] Further, the first load circuit comprises a three-phase compressor serving as a load and a first inverter circuit connected with the three-phase compressor.

[0018] The first inverter circuit has a fourth bridge arm composed of active switch tube Q2 and active switch tube Q3, a fifth bridge arm composed of active switch tube Q4 and active switch tube Q5, and a sixth bridge arm composed of active switch tube Q6 and active switch tube Q7.

[0019] The U phase of the three-phase compressor is connected to the midpoint of the fourth bridge arm, the V phase of the three-phase compressor is connected to the midpoint of the fifth bridge arm, and the W phase of the three-phase compressor is connected to the midpoint of the sixth bridge arm.

[0020] Further, the second load circuit comprises a three-phase motor serving as a load and a second inverter circuit connected with the three-phase motor.

[0021] The second inverter circuit has a seventh bridge arm composed of active switch tube Q8 and active switch tube Q9, an eighth bridge arm composed of active switch tube Q10 and active switch tube Q11, and a ninth bridge arm composed of active switch tube Q12 and active switch tube Q13.

[0022] The U phase of the three-phase motor is connected to the midpoint of the seventh bridge arm, the V phase of the three-phase motor is connected to the midpoint of the eighth bridge arm, and the W phase of the three-phase motor is connected to the midpoint of the ninth bridge arm.

[0023] Further, a protection circuit connected with the first inverter circuit is further included;

[0024] The protection circuit includes: a zener diode D7, a zener diode D8, a zener diode D9, a zener diode D10, a zener diode D11, a zener diode D12, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, and a resistor R6.

[0025] A control end of the active switch tube Q2 is connected to a control pin UP, a negative electrode of the zener diode D7 is connected between the control end of the active switch tube Q2 and the control pin UP, a positive electrode of the zener diode D7 is connected between a midpoint of the fourth bridge arm and a U phase of the three-phase compressor, and the resistor R1 is connected in parallel across the zener diode D7.

[0026] A control end of the active switch tube Q3 is connected to a control pin UN, a negative electrode of the zener diode D10 is connected between the control end of the active switch tube Q3 and the control pin UN, a positive electrode of the zener diode D10 is grounded, and the resistor R4 is connected in parallel across the zener diode D10.

[0027] A control end of the active switch tube Q4 is connected to a control pin VP, a negative electrode of the zener diode D8 is connected between the control end of the active switch tube Q4 and the control pin VP, a positive electrode of the zener diode D8 is connected between a midpoint of the fifth bridge arm and a V phase of the three-phase compressor, and the resistor R2 is connected in parallel across the zener diode D8.

[0028] A control end of the active switch tube Q5 is connected to a control pin VN, a negative electrode of the zener diode D11 is connected between the control end of the active switch tube Q5 and the control pin VN, a positive electrode of the zener diode D11 is grounded, and the resistor R5 is connected in parallel across the zener diode D11.

[0029] A control end of the active switch tube Q6 is connected to a control pin WP, a negative electrode of the zener diode D9 is connected between the control end of the active switch tube Q6 and the control pin WP, a positive electrode of the zener diode D9 is connected between a midpoint of the sixth bridge arm and a W phase of the three-phase compressor, and the resistor R3 is connected in parallel across the zener diode D9.

[0030] A control end of the active switch tube Q7 is connected to a control pin WN, a negative electrode of the zener diode D12 is connected between the control end of the active switch tube Q7 and the control pin WN, a positive electrode of the zener diode D12 is grounded, and the resistor R6 is connected in parallel across the zener diode D12.

[0031] Further, the first bus capacitor and the second bus capacitor are both thin film capacitors.

[0032] Further, when the three-phase motor is running in a noise frequency band, the current limiting unit controls the second bus capacitor to cut off the power supply path of the first bus capacitor.

[0033] When the three-phase motor is out of the noise frequency band, the current limiting unit controls the second bus capacitor to turn on the power supply path of the first bus capacitor.

[0034] The utility model also provides a kind of electric equipment, and the electric equipment has the above-mentioned drive protection circuit.

[0035] Compared with prior art, the utility model at least has following beneficial effects:

[0036] The utility model is provided with current limiting unit, it can adjust second bus capacitor to be the power supply path of first bus capacitor and turn on or cut off, when three-phase motor is running in noise frequency band, make the insulated gate bipolar transistor in current limiting unit cut off, first bus capacitor and second bus capacitor can be isolated due to the unidirectional conduction characteristic of power diode at this time, second bus capacitor will not be reversed for three-phase compressor function, so that second bus capacitor becomes the special electric energy of three-phase motor, avoid the noise problem brought under noise frequency band;

[0037] Meanwhile after being out of noise frequency band, the utility model can turn on insulated gate bipolar transistor, second bus capacitor can supply energy for three-phase compressor at this time, meet the load demand of three-phase compressor, relieve the current fluctuation amplitude of three-phase compressor. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the technical scheme in the embodiments of the utility model, the following will briefly introduce the drawings needed to be used in embodiment or prior art description, obviously, the drawings in the following description are only some embodiments of the utility model, and for those skilled in the art, other drawings can be obtained according to these drawings without paying creative labor.

[0039] Figure 1 It is the schematic diagram of the circuit connection of the utility model as a whole. DETAILED DESCRIPTION

[0040] In order to make the technical problem, technical scheme and beneficial effect of the utility model to be solved more clearly, the following will be further detailed to the utility model by combining with the drawings and embodiments.It should be understood that the specific embodiments described here are only used to explain the utility model, and are not used to limit the utility model.

[0041] Therefore, one feature described in the specification will be used to illustrate one feature of one embodiment of the present application, rather than implying that each embodiment of the present application must have the described feature. In addition, it should be noted that the specification describes many features. Although certain features can be combined together to show possible system designs, these features can also be used in other combinations that are not explicitly described. Therefore, unless otherwise stated, the described combinations are not intended to be limiting.

[0042] The principle and structure of the present application will be described in detail below in combination with the drawings and examples.

[0043] In the integrated driving circuit of the three-phase compressor and the three-phase motor, when the three-phase motor works in the noise frequency band, the bus capacitor connected with the three-phase motor at this time will affect the natural frequency, causing noise problems.

[0044] The present application proposes a driving protection circuit in view of the above problems, which comprises a rectifier bridge connected with an alternating current input, and the output end of the rectifier bridge is connected with a first bus capacitor and a second bus capacitor in sequence;

[0045] The first bus capacitor is connected with a first load circuit in the rear stage, the second bus capacitor is connected with a second load circuit in the rear stage, and a current limiting unit is connected in series on the direct current bus connecting the first bus capacitor and the second bus capacitor;

[0046] The current limiting unit can adjust the power supply path of the second bus capacitor to the first bus capacitor to be turned on or turned off.

[0047] Here, the first bus capacitor is a bus capacitor for supplying power to the three-phase compressor, and the second bus capacitor is a bus capacitor for supplying power to the three-phase motor. Without the current limiting unit described above, the noise problem as described above will occur;

[0048] After the current limiting unit is provided in the present application, the current of the second bus capacitor can be prevented from flowing to the three-phase compressor, and at this time, the second bus capacitor as the exclusive capacitor of the three-phase motor will not cause the noise problem as described above.

[0049] It can be seen that the present application can solve the noise problem in the prior art by the provision of the current limiting unit described above.

[0050] It should be pointed out that the three-phase motor and the three-phase compressor described above are only the setting mode under one preferred embodiment of the present application, and in other embodiments of the present application, the loads connected with the first bus capacitor and the second bus capacitor can also be not limited to the three-phase motor and the three-phase compressor described above, so as to realize the integration between other loads.

[0051] The current limiting unit comprises a power diode connected in series between the first bus capacitor and the second bus capacitor, and an insulated gate bipolar transistor connected in parallel with the power diode.

[0052] The positive electrode of the power diode is connected to the first bus capacitor, and the negative electrode of the power diode is connected to the second bus capacitor.

[0053] The control end of the insulated gate bipolar transistor is connected with a driving chip, and the driving chip is used for controlling the insulated gate bipolar transistor to be turned on or turned off.

[0054] Please refer to Figure 1 , which is a connection diagram of the driving protection circuit in the utility model, the power diode in the above-mentioned is a diode D13 in the attached Figure 1 , the insulated gate bipolar transistor is a switch tube Q1 in the attached Figure 1 , the first bus capacitor is a capacitor C1 in the attached Figure 1 , and the second bus capacitor is a capacitor C2 in the attached Figure 1 .

[0055] The working principle of the current limiting unit in the utility model will be described below with reference to the attached Figure 1 .

[0056] The diode itself has a one-way conduction characteristic, and since the positive electrode of the diode D13 is connected to the first bus capacitor and the negative electrode of the diode D13 is connected to the second bus capacitor, the direct current output by the rectifier bridge can be normally supplied to the second bus capacitor, and at the same time, the second bus capacitor is used to supply power to the three-phase motor, so as to ensure the normal operation of the three-phase motor.

[0057] When the switch tube Q1 is in the off state, the current flowing out of the second bus capacitor will be cut off when passing through the diode D13, and cannot flow into the first bus capacitor and supply power to the three-phase compressor, so that the second bus capacitor is equivalent to the exclusive capacitor of the three-phase motor at this time, and even if the three-phase motor operates in the noise frequency band, noise will not be generated.

[0058] After the three-phase motor is separated from the noise frequency band, the switch tube Q1 can be turned on through the driving chip at this time, and the driving chip is a Driver in the attached Figure 1 at this time, the current of the second bus capacitor can bypass the diode D13 and supply power to the three-phase compressor through the switch tube Q1, so that the load demand of the three-phase compressor can be met at this time, and the current fluctuation amplitude of the compressor is relieved.

[0059] It can be seen that the utility model realizes the separation of the first bus capacitor and the second bus capacitor through the above-mentioned current limiting unit, and avoids the occurrence of the above-mentioned noise problem.

[0060] Further, the above-mentioned alternating current input adopts three-phase alternating current power, and the rectifier bridge adopts a three-phase full-bridge circuit.

[0061] The three-phase full-bridge circuit has a first bridge arm composed of diode D1 and diode D2, a second bridge arm composed of diode D3 and diode D4, and a third bridge arm composed of diode D5 and diode D6.

[0062] The three-phase output of the three-phase alternating current power is connected to the midpoint of the first bridge arm, the midpoint of the second bridge arm, and the midpoint of the third bridge arm, respectively.

[0063] Here, the rectifier bridge functions to convert alternating current into direct current for charging the bus capacitor.

[0064] The rectifier bridge is set to the three-phase full-bridge circuit because the alternating current input is three-phase alternating current, and the load connected in the rear stage is also a three-phase load.

[0065] Further, the first load circuit in the utility model comprises a three-phase compressor serving as a load and a first inverter circuit connected with the three-phase compressor.

[0066] The first inverter circuit has a fourth bridge arm composed of active switch tube Q2 and active switch tube Q3, a fifth bridge arm composed of active switch tube Q4 and active switch tube Q5, and a sixth bridge arm composed of active switch tube Q6 and active switch tube Q7.

[0067] The U phase of the three-phase compressor is connected to the midpoint of the fourth bridge arm, the V phase of the three-phase compressor is connected to the midpoint of the fifth bridge arm, and the W phase of the three-phase compressor is connected to the midpoint of the sixth bridge arm.

[0068] The second load circuit comprises a three-phase motor serving as a load and a second inverter circuit connected with the three-phase motor.

[0069] The second inverter circuit has a seventh bridge arm composed of active switch tube Q8 and active switch tube Q9, an eighth bridge arm composed of active switch tube Q10 and active switch tube Q11, and a ninth bridge arm composed of active switch tube Q12 and active switch tube Q13.

[0070] The U phase of the three-phase motor is connected to the midpoint of the seventh bridge arm, the V phase of the three-phase motor is connected to the midpoint of the eighth bridge arm, and the W phase of the three-phase motor is connected to the midpoint of the ninth bridge arm.

[0071] Here, the first inverter circuit and the second inverter circuit have the same function, which is to convert the direct current power provided in the bus capacitor into alternating current power with a variable frequency, thereby supplying power to the corresponding three-phase compressor and three-phase motor.

[0072] The frequency of the alternating current power provided by the first inverter circuit and the second inverter circuit can be set by controlling the turn-on frequency of the upper arm switch and the lower arm switch of the corresponding bridge arm, and the size of the alternating current power output by the first inverter circuit and the second inverter circuit can be adjusted by adjusting the turn-on duty cycle of each active switch tube.

[0073] As shown in Figure 1 For the active switch tube Q2 in the first inverter circuit, the control end thereof is connected to the control pin UP, which can turn on the active switch tube Q2 when a high-level signal is sent and make the active switch tube Q2 cut off when a low-level signal is sent. The control pin UP can be connected to a single-chip microcomputer for control to send different driving signals, thereby realizing control of the turn-on and cut-off of the active switch tube Q2.

[0074] For the active switch tube Q3 in the first inverter circuit, the control end thereof is connected to the control pin UN, which can turn on the active switch tube Q3 when a high-level signal is sent and make the active switch tube Q3 cut off when a low-level signal is sent. The control pin UN can be connected to a single-chip microcomputer for control to send different driving signals, thereby realizing control of the turn-on and cut-off of the active switch tube Q3.

[0075] For the active switch tube Q4 in the first inverter circuit, the control end thereof is connected to the control pin VP, which can turn on the active switch tube Q4 when a high-level signal is sent and make the active switch tube Q4 cut off when a low-level signal is sent. The control pin VP can be connected to a single-chip microcomputer for control to send different driving signals, thereby realizing control of the turn-on and cut-off of the active switch tube Q4.

[0076] For the active switch tube Q5 in the first inverter circuit, the control end thereof is connected to the control pin VN, which can turn on the active switch tube Q5 when a high-level signal is sent and make the active switch tube Q5 cut off when a low-level signal is sent. The control pin VN can be connected to a single-chip microcomputer for control to send different driving signals, thereby realizing control of the turn-on and cut-off of the active switch tube Q5.

[0077] For the active switch tube Q6 in the first inverter circuit, the control end thereof is connected to the control pin WP, which can turn on the active switch tube Q6 when a high-level signal is sent and make the active switch tube Q6 cut off when a low-level signal is sent. The control pin WP can be connected to a single-chip microcomputer for control to send different driving signals, thereby realizing control of the turn-on and cut-off of the active switch tube Q6.

[0078] The control end of the active switch tube Q7 in the first inverter circuit is connected to a control pin WN, which can turn on the active switch tube Q7 when sending a high-level signal and make the active switch tube Q7 cut off when sending a low-level signal. The control pin WM can be connected to a single-chip microcomputer for control to send different driving signals, so as to realize the control of the on and off of the active switch tube Q7.

[0079] Therefore, the single-chip microcomputer is connected to the control pins UP, UN, VP, VN, WP and WN, so that the control of the output voltage, frequency and period of the whole first inverter circuit can be realized, and the control requirement of the three-phase compressor under various working conditions can be met.

[0080] Here, the second driving circuit can also be controlled by the single-chip microcomputer, and the specific setting is consistent with that of the first driving circuit, which will not be repeated here.

[0081] Further, in order to prevent the voltage overshoot and the current from being too large to damage the active switch tubes in the first driving circuit, the driving protection circuit of the utility model further comprises a protection circuit connected with the first inverter circuit.

[0082] The protection circuit comprises a zener diode D7, a zener diode D8, a zener diode D9, a zener diode D10, a zener diode D11, a zener diode D12, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5 and a resistor R6.

[0083] The control end of the active switch tube Q2 is connected to the control pin UP, the negative electrode of the zener diode D7 is connected between the control end of the active switch tube Q2 and the control pin UP, the positive electrode of the zener diode D7 is connected between the midpoint of the fourth bridge arm and the U phase of the three-phase compressor, and the resistor R1 is connected in parallel across the zener diode D7.

[0084] The control end of the active switch tube Q3 is connected to the control pin UN, the negative electrode of the zener diode D10 is connected between the control end of the active switch tube Q3 and the control pin UN, the positive electrode of the zener diode D10 is grounded, and the resistor R4 is connected in parallel across the zener diode D10.

[0085] The control end of the active switch tube Q4 is connected to the control pin VP, the negative electrode of the zener diode D8 is connected between the control end of the active switch tube Q4 and the control pin VP, the positive electrode of the zener diode D8 is connected between the midpoint of the fifth bridge arm and the V phase of the three-phase compressor, and the resistor R2 is connected in parallel across the zener diode D8.

[0086] The control end of the active switch tube Q5 is connected to the control pin VN, the negative electrode of the voltage stabilizing diode D11 is connected between the control end of the active switch tube Q5 and the control pin VN, the positive electrode of the voltage stabilizing diode D11 is grounded, and the resistor R5 is connected in parallel between the voltage stabilizing diode D11;

[0087] The control end of the active switch tube Q6 is connected to the control pin WP, the negative electrode of the voltage stabilizing diode D9 is connected between the control end of the active switch tube Q6 and the control pin WP, the positive electrode of the voltage stabilizing diode D9 is connected between the midpoint of the sixth bridge arm and the W phase of the three-phase compressor, and the resistor R3 is connected in parallel between the voltage stabilizing diode D9;

[0088] The control end of the active switch tube Q7 is connected to the control pin WN, the negative electrode of the voltage stabilizing diode D12 is connected between the control end of the active switch tube Q7 and the control pin WN, the positive electrode of the voltage stabilizing diode D12 is grounded, and the resistor R6 is connected in parallel between the voltage stabilizing diode D12.

[0089] Here, the voltage stabilizing diode functions to stabilize voltage and ensure that the voltage of the circuit is maintained within a certain range, thereby protecting other components in the circuit from damage, and thus mainly functions to prevent voltage overshoot in the first inverter circuit;

[0090] The resistors R1 to R6 function to limit current and prevent overcurrent burnout problems in the first inverter circuit.

[0091] It should be noted that the protective circuit is only provided in the first inverter circuit, because, on the three-phase motor side, it is generally internally packaged by the manufacturer, and thus generally does not have peripheral circuit expansion, and in actual design, if the reliability of the circuit needs to be increased, the protective circuit can also be provided to avoid damage to the second inverter circuit.

[0092] Further, the first bus capacitor and the second bus capacitor in the utility model are both thin film capacitors.

[0093] The thin film capacitor is used to replace the electrolytic capacitor, which is a reliable choice for implementing frequency conversion and frequency drive technology in household and commercial air conditioning products, and compared with the scheme using the electrolytic capacitor, the thin film capacitor can improve the service life of the drive board.

[0094] The control logic in the utility model is as follows:

[0095] When the three-phase motor operates in a noise frequency band, the current limiting unit controls the second bus capacitor to cut off the power supply path of the first bus capacitor;

[0096] When the three-phase motor is out of the noise frequency band, the current limiting unit controls the second bus capacitor to turn on the power supply path of the first bus capacitor.

[0097] Based on the above control logic, the overall operation process of the utility model is:

[0098] The three-phase alternating current is first rectified into direct current by the rectifier bridge, at this time, the PN end of the rectifier bridge is the bus voltage, since the inherent frequency of the three-phase compressor and the three-phase motor is generally low, when the bus voltage fluctuation causes the current to follow the fluctuation frequency, it will cause the operation noise problem of the three-phase motor.

[0099] The utility model adds a power diode D13 and a reverse parallel IGBT (namely the insulated gate bipolar transistor in the foregoing text) on the direct current bus, the power diode D13 separates the two film capacitors C1 and C2, when the power diode D13 is turned on, the capacitor C2 will not reversely supply power to the three-phase compressor load, thereby the capacitor C2 forms a special capacitor for the three-phase motor, in the normal operation state of the unit and in the "noise" frequency band of the three-phase motor, the special capacitor can effectively solve the noise problem caused by the mutual influence of the bus fluctuation frequency and the inherent frequency of the three-phase motor;

[0100] When the operation frequency of the three-phase motor is out of the "noise" frequency band, through MCU control, a signal is sent to the drive chip (namely the Driver in the attached Figure 1 ), the drive chip amplifies the power to control signal to the insulated gate bipolar transistor Q1 and makes the insulated gate bipolar transistor Q1 conduct, thereby the reverse path of the power diode D13 is "short-circuited", at this time, the capacitor C2 can reversely supply power to the three-phase compressor, for the compressor side, the capacitance value of the capacitor is increased, which meets the load demand of the three-phase compressor and relieves the current fluctuation amplitude of the three-phase compressor.

[0101] In summary, compared with the prior art, the utility model has at least the following beneficial effects:

[0102] The utility model is provided with a current limiting unit, which can adjust the power supply path of the second bus capacitor to the first bus capacitor to be turned on or cut off, when the three-phase motor operates in the noise frequency band, the insulated gate bipolar transistor in the current limiting unit is cut off, at this time, the first bus capacitor and the second bus capacitor are separated due to the one-way conduction characteristic of the power diode, the second bus capacitor will not reversely function for the three-phase compressor, thereby the second bus capacitor becomes a special electric energy for the three-phase motor, avoiding the noise problem in the noise frequency band;

[0103] At the same time, after being out of the noise frequency band, the utility model can turn on the insulated gate bipolar transistor, at this time, the second bus capacitor can supply power to the three-phase compressor, meeting the load demand of the three-phase compressor and relieving the current fluctuation amplitude of the three-phase compressor.

[0104] The utility model discloses still provided a kind of electric equipment, which has the above-mentioned drive protection circuit.

[0105] Further, the above-mentioned electric equipment is an air conditioner.

[0106] The above description is only a preferred embodiment of the utility model, and is not used to limit the utility model, and any modification, equivalent replacement and improvement made within the spirit and principle of the utility model should be included in the protection scope of the utility model.

Claims

1. A drive protection circuit, characterized by, The rectifier bridge connected with the AC input, the output of the rectifier bridge is connected with the first bus capacitor and the second bus capacitor in turn; The first bus capacitor is connected with the first load circuit, the second bus capacitor is connected with the second load circuit, the current limiting unit is connected in series on the DC bus connecting the first bus capacitor and the second bus capacitor; The current limiting unit can adjust the second bus capacitor to be on or off in the power supply path of the first bus capacitor.

2. The drive protection circuit according to claim 1, characterized in that, The current limiting unit comprises a power diode connected in series between the first bus capacitor and the second bus capacitor, and an insulated gate bipolar transistor connected in parallel with the power diode; The positive electrode of the power diode is connected to the first bus capacitor, and the negative electrode of the power diode is connected to the second bus capacitor; The control end of the insulated gate bipolar transistor is connected with a driving chip, and the driving chip is used for controlling the insulated gate bipolar transistor to be on or off.

3. The drive protection circuit of claim 1, wherein, The AC input adopts a three-phase AC power supply, and the rectifier bridge adopts a three-phase full-bridge circuit; The three-phase full-bridge circuit has a first bridge arm composed of diode D1 and diode D2, a second bridge arm composed of diode D3 and diode D4, and a third bridge arm composed of diode D5 and diode D6; The three-phase output of the three-phase AC power supply is connected to the midpoint of the first bridge arm, the midpoint of the second bridge arm, and the midpoint of the third bridge arm respectively.

4. The drive protection circuit of claim 1, wherein, The first load circuit comprises a three-phase compressor as a load and a first inverter circuit connected with the three-phase compressor; The first inverter circuit has a fourth bridge arm composed of active switch tube Q2 and active switch tube Q3, a fifth bridge arm composed of active switch tube Q4 and active switch tube Q5, and a sixth bridge arm composed of active switch tube Q6 and active switch tube Q7; The U phase of the three-phase compressor is connected to the midpoint of the fourth bridge arm, the V phase of the three-phase compressor is connected to the midpoint of the fifth bridge arm, and the W phase of the three-phase compressor is connected to the midpoint of the sixth bridge arm.

5. The drive protection circuit of claim 1, wherein, The second load circuit comprises a three-phase motor as a load and a second inverter circuit connected with the three-phase motor; The second inverter circuit has a seventh bridge arm composed of active switch tube Q8 and active switch tube Q9, an eighth bridge arm composed of active switch tube Q10 and active switch tube Q11, and a ninth bridge arm composed of active switch tube Q12 and active switch tube Q13; The U phase of the three-phase motor is connected to the midpoint of the seventh bridge arm, the V phase of the three-phase motor is connected to the midpoint of the eighth bridge arm, and the W phase of the three-phase motor is connected to the midpoint of the ninth bridge arm.

6. The drive protection circuit of claim 4, wherein, A protection circuit connected with the first inverter circuit is further included; The protection circuit comprises: voltage stabilizing diode D7, voltage stabilizing diode D8, voltage stabilizing diode D9, voltage stabilizing diode D10, voltage stabilizing diode D11, voltage stabilizing diode D12, resistor R1, resistor R2, resistor R3, resistor R4, resistor R5, and resistor R6. The control end of the active switch tube Q2 is connected to a control pin UP, the negative electrode of a voltage stabilizing diode D7 is connected between the control end of the active switch tube Q2 and the control pin UP, the positive electrode of the voltage stabilizing diode D7 is connected between the midpoint of the fourth bridge arm and the U phase of the three-phase compressor, and the resistor R1 is connected in parallel across the voltage stabilizing diode D7; The control end of the active switch tube Q3 is connected to a control pin UN, the negative electrode of a voltage stabilizing diode D10 is connected between the control end of the active switch tube Q3 and the control pin UN, the positive electrode of the voltage stabilizing diode D10 is grounded, and the resistor R4 is connected in parallel across the voltage stabilizing diode D10; The control end of the active switch tube Q4 is connected to a control pin VP, the negative electrode of a voltage stabilizing diode D8 is connected between the control end of the active switch tube Q4 and the control pin VP, the positive electrode of the voltage stabilizing diode D8 is connected between the midpoint of the fifth bridge arm and the V phase of the three-phase compressor, and the resistor R2 is connected in parallel across the voltage stabilizing diode D8; The control end of the active switch tube Q5 is connected to a control pin VN, the negative electrode of a voltage stabilizing diode D11 is connected between the control end of the active switch tube Q5 and the control pin VN, the positive electrode of the voltage stabilizing diode D11 is grounded, and the resistor R5 is connected in parallel across the voltage stabilizing diode D11; The control end of the active switch tube Q6 is connected to a control pin WP, the negative electrode of a voltage stabilizing diode D9 is connected between the control end of the active switch tube Q6 and the control pin WP, the positive electrode of the voltage stabilizing diode D9 is connected between the midpoint of the sixth bridge arm and the W phase of the three-phase compressor, and the resistor R3 is connected in parallel across the voltage stabilizing diode D9; The control end of the active switch tube Q7 is connected to a control pin WN, the negative electrode of a voltage stabilizing diode D12 is connected between the control end of the active switch tube Q7 and the control pin WN, the positive electrode of the voltage stabilizing diode D12 is grounded, and the resistor R6 is connected in parallel across the voltage stabilizing diode D12.

7. The drive protection circuit of claim 1, wherein, The first bus capacitor and the second bus capacitor are both thin film capacitors.

8. The drive protection circuit of claim 5, wherein, When the three-phase motor operates in a noise frequency band, the current limiting unit controls the second bus capacitor to cut off the power supply path of the first bus capacitor; When the three-phase motor is out of the noise frequency band, the current limiting unit controls the second bus capacitor to turn on the power supply path of the first bus capacitor.

9. An electric device, characterized by The power consumption device has the drive protection circuit as claimed in any one of claims 1 to 8.

10. The powered device of claim 9, wherein, The power consumption device is an air conditioner.

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