Misconduction control circuit, inverter, frequency converter and frequency conversion electric appliance

Abstract

The utility model discloses a misconduction control circuit, an inverter, a frequency converter and a frequency conversion electric appliance. The error conduction control circuit is applied to the inverter, the inverter comprises a plurality of inverter bridges, each inverter bridge comprises an upper bridge arm switch tube and a lower bridge arm switch tube, and the error conduction control circuit comprises clamping modules which are arranged in one-to-one correspondence with the lower bridge arm switch tubes, the first end of the clamping module is connected with the source electrode of the lower bridge arm switch tube, and the second end of the clamping module is connected with the grid electrode of the lower bridge arm switch tube. According to the utility model, the voltage difference between the grid electrode and the source electrode of the lower bridge arm switch tube can be prevented from exceeding the conduction threshold value of the lower bridge arm switch tube, so that the lower bridge arm switch tube is prevented from being mistakenly conducted when the lower bridge arm switch tube does not need to be conducted, and the short circuit caused by simultaneous conduction of the upper bridge arm switch tube and the lower bridge arm switch tube of the same inverter bridge is avoided; and the reliability and the stability of the inverter circuit are improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to electronic power technology field, specifically, a misdirected control circuit, inverter, frequency converter and frequency electric appliance. BACKGROUND

[0002] With the development of electronic power technology field, inverter has gradually matured in the motor control field, and the inverter is usually a full-bridge circuit composed of power switch tubes, which converts direct current into alternating current by using the switching characteristics of the power switch tubes, and the power switch tubes in the inverter are alternately and orderly turned on, if the two power switch tubes of the same bridge arm are turned on at the same time, a short circuit will occur, in order to solve this problem, the dead time of the upper and lower power switch tubes of the same bridge arm is set in the software program, but when the line between the control ground of the PWM chip and the source of the lower bridge arm switch tube is too long, a surge negative voltage will be generated at the source of the lower bridge arm switch tube, resulting in misdirected of the lower bridge arm switch tube, at this time, if the corresponding upper bridge arm is also turned on, a short circuit problem will occur.

[0003] In view of the problem that the surge negative voltage is generated at the source of the lower bridge arm switch tube in the inverter in the prior art, resulting in misdirected of the lower bridge arm switch tube, and further resulting in short circuit, no effective solution has been proposed so far. SUMMARY

[0004] The misdirected control circuit, inverter, frequency converter and frequency electric appliance provided in the embodiment of the utility model solve the problem that the surge negative voltage is generated at the source of the lower bridge arm switch tube in the inverter in the prior art, resulting in misdirected of the lower bridge arm switch tube, and further resulting in short circuit.

[0005] To solve the above technical problems, the utility model provides a kind of misdirected control circuit, it is applied to inverter, and the inverter includes multiple inverter bridges, and the inverter bridge includes upper bridge arm switch tube and lower bridge arm switch tube, and the misdirected control circuit includes:

[0006] Further, the clamping module includes a clamping diode, the anode of the clamping diode is connected to the source of the lower bridge arm switch tube, and the cathode of the clamping diode is connected to the gate of the lower bridge arm switch tube.

[0007] Further, the clamping module includes a clamping diode, the anode of the clamping diode is connected to the source of the lower bridge arm switch tube, and the cathode of the clamping diode is connected to the gate of the lower bridge arm switch tube.

[0008] Further, the misdirected control circuit further includes:

[0009] A negative voltage consumption module is arranged between the source of each lower bridge arm switch tube and the power ground in one-to-one correspondence, the first end of which is connected to the source of the lower bridge arm switch tube, the second end of which is connected to the power ground, and the third end of which is connected to the isolation ground.

[0010] Further, the negative voltage consumption module comprises:

[0011] A controllable switch tube, the control end of which is connected to the power ground, the output end of which is connected to the source of the lower bridge arm switch tube, and the input end of which is connected to the isolation ground through a resistance unit;

[0012] The resistance unit is used to consume the negative voltage at the source of the lower bridge arm switch tube.

[0013] Further, the resistance unit comprises at least one cement resistance;

[0014] If the number of cement resistances is two, the cement resistances are connected in series or in parallel;

[0015] If the number of cement resistances is three or more, the cement resistances are connected in series, in parallel or in mixed connection.

[0016] Further, the controllable switch tube is a P-channel MOS tube or a P-type triode.

[0017] The utility model also provides an inverter, including multiple inverter bridges, the inverter bridge includes upper bridge arm switch tube and lower bridge arm switch tube, still include above-mentioned misdirect on control circuit.

[0018] The utility model also provides a frequency converter, including above-mentioned inverter.

[0019] The utility model also provides a frequency conversion electric appliance, including above-mentioned frequency converter.

[0020] Further, the frequency conversion electric appliance at least includes one of the following: a frequency conversion air conditioner, a frequency conversion refrigerator, a frequency conversion washing machine.

[0021] The technical scheme of the utility model, by setting the clamping module between the gate and the source of the lower bridge arm switch tube, clamps the voltage difference between the gate and the source of the lower bridge arm switch tube to a certain value, prevents the voltage difference between the gate and the source of the lower bridge arm switch tube from exceeding the conduction threshold of the lower bridge arm switch tube, and further avoids the misdirect on of the lower bridge arm switch tube when it should not be conducted, and further avoids the simultaneous conduction of the upper bridge arm switch tube and the lower bridge arm switch tube of the same inverter bridge, which causes short circuit, and improves the reliability and stability of the inverter circuit. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1Structure diagram of the inverter according to the embodiment of the present application;

[0023] Figure 2 Structure diagram of the misdirected on control circuit according to the embodiment of the present application. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0025] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. "Multiple" generally includes at least two.

[0026] It should be understood that the term "and / or" used herein is only to describe the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B can represent: A exists alone, A and B exist together, and B exists alone. In addition, the character " / " in this paper generally represents that the front and rear associated objects are a "or" relationship.

[0027] It should be understood that although the terms first, second, third, etc. may be used in the embodiments of the present application to describe power switching tubes, these power switching tubes should not be limited to these terms. These terms are only used to distinguish different power switching tubes. For example, the first power switching tube can also be referred to as the second power switching tube without departing from the scope of the embodiments of the present application, and similarly, the second power switching tube can also be referred to as the first power switching tube.

[0028] Depending on the context, the word "if" as used herein can be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting". Similarly, depending on the context, the phrase "if determined" or "if detecting (a stated condition or event)" can be interpreted as "when determined" or "in response to determining" or "when detecting (a stated condition or event)" or "in response to detecting (a stated condition or event)".

[0029] It is also important to note that the terms "comprises" and / or "comprising", or other variations such as "includes", "including" or "contains", "containing" shall not be construed as the use of an exclusive or exhaustive listing of the elements contained therein. The term "consisting essentially of" or grammatical variations thereof, when used in a claim, shall mean that the claim is composed of the recited elements, and that no other elements are present which significantly affect the characteristics of the composition or method. The term "consisting of" or grammatical variations thereof, when used in a claim, shall mean that the claim is composed of the recited elements, and that no other elements are present in the composition or method.

[0030] Optional embodiments of the present application will be described in detail below with reference to the drawings.

[0031] Embodiment 1

[0032] With the development of the field of electronic power technology, the inverter has gradually matured in the field of motor control, and the inverter is usually a full-bridge circuit composed of power switch tubes. The inverter converts direct current into alternating current by using the switching characteristics of the power switch tube. The power switch tube in the inverter needs to be turned on alternately and orderly. If the two power switch tubes in the same bridge arm are turned on at the same time, a short circuit will occur. In order to solve this problem, a dead time is usually set in the software program for the turn-on of the upper and lower power switch tubes in the same bridge arm. However, when the line between the control ground of the PWM chip and the source of the lower bridge arm switch tube is too long, a surge negative voltage will be generated at the source of the lower bridge arm switch tube, causing the lower bridge arm switch tube to be mis-conducted. At this time, if the corresponding upper bridge arm is also turned on, a short circuit problem will occur.

[0033] In view of the problem that a surge negative voltage is generated at the source of the lower bridge arm switch tube in the inverter in the prior art, causing the lower bridge arm switch tube to be mis-conducted, and further causing a short circuit, the present embodiment provides a mis-conduction control circuit applied to an inverter, Figure 1 The structure diagram of the inverter according to the embodiment of the present application is shown in Figure 1As shown, the inverter includes a plurality of inverter bridges, each inverter bridge including an upper bridge arm switch tube and a lower bridge arm switch tube, in this embodiment, the number of inverter bridges is three, the first inverter bridge includes the first power switch tube Q1, the second power switch tube Q2, the first power switch tube Q1 and the second power switch tube Q2 are connected by a line to connect the first phase of the motor, the second inverter bridge includes the third power switch tube Q3, the fourth power switch tube Q4, the third power switch tube Q3 and the fourth power switch tube Q4 are connected by a line to connect the second phase of the motor, the third inverter bridge includes the fifth power switch tube Q5, the sixth power switch tube Q6, the fifth power switch tube Q5 and the sixth power switch tube Q6 are connected by a line to connect the third phase of the motor, the first power switch tube Q1, the third power switch tube Q3 and the fifth power switch tube Q5 are upper bridge arm switch tubes, the second power switch tube Q2, the fourth power switch tube Q4 and the sixth power switch tube Q6 are upper bridge arm switch tubes, the PWM chip sends six control signals PWM1-PWM6, which control the on-off of the power switch tubes Q1-Q6, such as Figure 1 As shown, the misdirected on control circuit includes: a clamping module 10, which is arranged one-to-one corresponding to the lower bridge arm switch tube, the first end of the clamping module 10 is connected to the source of the lower bridge arm switch tube, and the second end of the clamping module is connected to the gate of the lower bridge arm switch tube, the voltage difference between the gate and the source of the lower bridge arm switch tube is clamped to a certain value through the clamping module 10, so as to avoid the misdirected on of the lower bridge arm switch tube, and it should be noted that in actual application, the clamping module 10 is arranged between the gate and the source of each lower bridge arm switch tube, and the clamping module 10 is also arranged between the source and the gate of the fourth power switch tube Q4 and the sixth power switch tube Q6.

[0034] The misdirected on control circuit of the embodiment prevents the voltage difference between the gate and the source of the lower bridge arm switch tube from exceeding the on threshold of the lower bridge arm switch tube by arranging the clamping module 10 between the gate and the source of the lower bridge arm switch tube, thereby avoiding the misdirected on of the lower bridge arm switch tube when it should not be on, and avoiding the simultaneous on of the upper bridge arm switch tube and the lower bridge arm switch tube of the same inverter bridge, which causes short circuit, thereby improving the reliability and stability of the inverter circuit.

[0035] Figure 2 The structure diagram of the misdirected on control circuit according to the embodiment of the utility model is shown in the figure, Figure 2 As shown, the clamping module includes a clamping diode D, the anode of the clamping diode D is connected to the source of the lower bridge arm switch tube, and the cathode of the clamping diode is connected to the gate of the lower bridge arm switch tube.

[0036] After the clamping diode is arranged between the source S and the gate G of the lower bridge arm switch tube, the unidirectional conduction characteristic of the diode can clamp the negative voltage, but clamping the negative voltage cannot completely consume the negative voltage. In order to consume the negative voltage, the above mis-conduction control circuit further comprises: a negative voltage consumption module 20, which is arranged one by one between the source of each lower bridge arm switch tube and the power ground GND2, the first end of which is connected to the source of the lower bridge arm switch tube, the second end of which is connected to the power ground GND2, and the third end of which is connected to the isolation ground GND3. As shown in Figure 2 The negative voltage consumption module 20 comprises: a controllable switch tube Q, the control end of which is connected to the power ground GND2, the output end of which is connected to the source of the lower bridge arm switch tube, and the input end of which is connected to the isolation ground GND3 through a resistance unit 201; and the resistance unit 201 is used for consuming the negative voltage at the source of the lower bridge arm switch tube. As shown in Figure 2 In the present example, the resistance unit 201 comprises two cement resistors R1 and R2 connected in series, and in other embodiments of the utility model, the resistance unit 201 comprises at least one cement resistor; if the number of cement resistors is two, the cement resistors are connected in series or in parallel; if the number of cement resistors is three or more, the cement resistors are connected in series, in parallel or in a mixed manner, wherein the mixed manner refers to a combination of series and parallel connection, for example, when the number of cement resistors is three, two of the cement resistors can be connected in series, and the third cement resistor is connected in parallel, or two of the cement resistors are connected in parallel, and the third cement resistor is connected in series.

[0037] In order to ensure that the controllable switch tube is turned on when the negative voltage is generated at the source of the lower bridge arm switch tube, the above controllable switch tube is a P-channel MOS tube or a P-type triode.

[0038] In summary, the normal inverter circuit is a full-bridge inverter circuit composed of six power devices. Due to the long loop of the power ground GND2 and the control ground GND1 and many other factors in the actual PCB drawing process, a surge negative voltage can be generated at the source S of the lower bridge arm switch tube, for example, the turn-on voltage of the lower bridge arm switch tube is 5V, and the negative voltage is exactly ≤-5V. When the control signal of PWM2 is 0V, that is, the second power switch tube Q2 is not turned on under the control of the software program, the gate G of Q2 is 0V. At this time, 0V-(-5V)≥5V will cause the mis-conduction of the second power switch tube Q2. In this case, if the first switch tube Q1 is in the on state, the power Vin is directly short-circuited to the ground.

[0039] In the embodiment, a false conduction control circuit is added between the gate and the source of the lower bridge arm, and the false conduction control circuit comprises a clamping diode and a controllable switch tube, and cement resistors R1 and R2. The clamping diode D1 is added between the source S and the gate G of the lower bridge arm switch tube, and the negative voltage is clamped by using the unidirectional conduction of the diode. However, the negative voltage cannot be completely consumed by only clamping the negative voltage. The controllable switch Q is turned on when the negative voltage at the source S of the lower bridge arm switch tube is less than -5V by using the negative voltage conduction characteristic of the controllable switch Q. Then, the negative voltage sequentially passes through the controllable switch Q, the cement resistors R1 and R2, and the isolation ground GND3 to form a new loop, and the negative voltage at the source S of the bridge arm switch tube is consumed by using the cement resistors.

[0040] Embodiment 2

[0041] The embodiment provides an inverter, as described in the above-mentioned Figure 1 The inverter comprises a plurality of inverter bridges, and further comprises the false conduction control circuit in the above-mentioned embodiments, so that the voltage difference between the gate and the source of the lower bridge arm switch tube is prevented from exceeding the conduction threshold of the lower bridge arm switch tube, and then the false conduction of the lower bridge arm switch tube at a time when the lower bridge arm switch tube should not be conducted is avoided, and then the short circuit caused by the simultaneous conduction of the upper bridge arm switch tube and the lower bridge arm switch tube of the same inverter bridge is avoided, and the reliability and stability of the inverter circuit are improved.

[0042] Embodiment 3

[0043] The embodiment provides a frequency converter, which comprises the above-mentioned inverter, so that the voltage difference between the gate and the source of the lower bridge arm switch tube is prevented from exceeding the conduction threshold of the lower bridge arm switch tube, and then the false conduction of the lower bridge arm switch tube at a time when the lower bridge arm switch tube should not be conducted is avoided, and then the short circuit caused by the simultaneous conduction of the upper bridge arm switch tube and the lower bridge arm switch tube of the same inverter bridge is avoided, and the reliability and stability of the inverter circuit are improved, and then the reliability and stability of the whole frequency converter are improved.

[0044] Embodiment 4

[0045] The embodiment provides a frequency conversion electric appliance, which comprises the above-mentioned frequency converter, so that the voltage difference between the gate and the source of the lower bridge arm switch tube is prevented from exceeding the conduction threshold of the lower bridge arm switch tube, and then the false conduction of the lower bridge arm switch tube at a time when the lower bridge arm switch tube should not be conducted is avoided, and then the short circuit caused by the simultaneous conduction of the upper bridge arm switch tube and the lower bridge arm switch tube of the same inverter bridge is avoided, and the reliability and stability of the inverter circuit are improved, and then the reliability and stability of the whole frequency converter are improved, and finally the reliability and stability of the whole frequency conversion electric appliance are improved.

[0046] In some embodiments of the utility model, the frequency conversion electric appliance at least includes one of the following: a frequency conversion air conditioner, a frequency conversion refrigerator, a frequency conversion washing machine.

[0047] The circuit embodiments described above are merely illustrative, wherein the modules described as separate components can or can not be physically separated, and the components shown as modules can or can not be physical modules, i.e., can be located in one place or distributed on multiple network units. Part or all of the modules can be selected to achieve the purposes of the embodiments according to actual needs.

[0048] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A misfire control circuit applied to an inverter, the inverter comprising a plurality of inverter bridges, the inverter bridge comprising an upper bridge arm switch and a lower bridge arm switch, characterized in that, The mis-conduction control circuit comprises: A clamping module is arranged in one-to-one correspondence with the lower bridge arm switch tube, a first end of the clamping module is connected to a source of the lower bridge arm switch tube, and a second end of the clamping module is connected to a gate of the lower bridge arm switch tube.

2. The misdirected call control circuit of claim 1, wherein, The clamping module comprises a clamping diode, an anode of the clamping diode is connected to the source of the lower bridge arm switch tube, and a cathode of the clamping diode is connected to the gate of the lower bridge arm switch tube.

3. The misdirected call control circuit of claim 1, wherein, The mis-conduction control circuit further comprises: A negative voltage consumption module is arranged in one-to-one correspondence between the source of each lower bridge arm switch tube and a power ground, a first end of the negative voltage consumption module is connected to the source of the lower bridge arm switch tube, a second end of the negative voltage consumption module is connected to the power ground, and a third end of the negative voltage consumption module is connected to an isolation ground.

4. The misdirected call control circuit of claim 3, wherein, The negative voltage consumption module comprises: A controllable switch tube, a control end of the controllable switch tube is connected to the power ground, an output end of the controllable switch tube is connected to the source of the lower bridge arm switch tube, and an input end of the controllable switch tube is connected to the isolation ground through a resistance unit; The resistance unit is used for consuming negative voltage at the source of the lower bridge arm switch tube.

5. The misdirected call control circuit of claim 4, wherein, The resistance unit comprises at least one cement resistance; If the number of the cement resistances is two, the cement resistances are connected in series or in parallel; If the number of the cement resistances is three or more, the cement resistances are connected in series, in parallel, or in mixed connection.

6. The misdirected call control circuit of claim 4, wherein, The controllable switch tube is a P-channel MOS tube or a P-type triode.

7. An inverter comprising a plurality of inverter bridges, the inverter bridges comprising upper and lower bridge arm switching devices, characterized in that, The mis-conduction control circuit of any one of claims 1 to 6 is further included.

8. A frequency converter, characterized in that The inverter of claim 7 is included.

9. A variable frequency electric appliance characterized by comprising: The frequency converter of claim 8 is included.

10. The variable frequency appliance of claim 9, wherein, The frequency conversion electric appliance at least comprises one of the following: a variable frequency air conditioner, a variable frequency refrigerator, and a variable frequency washing machine.

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