Inverter structure and control method

Abstract

The invention provides an inverter structure and a control method, the inverter structure comprises a control circuit, the control circuit is provided with an inverter component and a control switch K used for controlling the inverter component to output or close; the comparison circuit is connected with the control circuit so as to receive the current on the control circuit; the protection circuit is in signal connection with the control circuit; the comparison circuit outputs a signal to the protection circuit according to the received current on the control circuit; and the protection circuit controls the control switch K to be switched on or switched off according to the signal output by the comparison circuit. The inverter structure solves the technical problem that the inverter is easy to damage.

Description

Technical Field

[0001] The present invention relates to the technical field of inverters, and in particular to an inverter structure and a control method. Background Art

[0002] At present, commercial air-conditioning products are being widely adopted in frequency conversion, and the reliability of frequency conversion drive technology is receiving more and more attention. Three-phase commercial air conditioners have large power and generally high current, which are prone to current overshoot in harsh or unavoidable conditions, which can easily cause damage to the drive board and increase customer and after-sales maintenance costs. Therefore, overcurrent protection has become the most important part of current drive control.

[0003] However, the traditional over-current protection method is to obtain a large current by sampling, and the DSP turns off the PWM output to achieve an over-current protection. This method does not directly shut down the circuit, the reaction speed is slow, and it is easy to damage the circuit.

[0004] Therefore, the prior art needs to be further developed. Summary of the invention

[0005] The purpose of the present invention is to overcome the above technical deficiencies and provide an inverter structure and a control method to solve the technical problem that the inverter is easily damaged in the related art.

[0006] In order to achieve the above technical objectives, the present invention adopts the following technical solutions: an inverter structure is provided, including: a control circuit, on which an inverter component and a control switch K1 for controlling the output or shutdown of the inverter component are arranged; a comparison circuit, which is connected to the control circuit to receive the current on the control circuit; a protection circuit, which is connected to the control circuit signal; the comparison circuit outputs a signal to the protection circuit according to the received current on the control circuit; the protection circuit controls the control switch K1 to be closed or opened according to the signal output by the comparison circuit.

[0007] Furthermore, the control circuit includes: a P-phase circuit connected to the inverter component; an N-phase circuit connected to the inverter component; a comparison circuit connected to the N-phase circuit; a connecting circuit, one end of the connecting circuit is connected to the P-phase circuit, and the other end of the connecting circuit is connected to the N-phase circuit; and a capacitor is arranged on the connecting circuit.

[0008] Furthermore, there are multiple capacitors, which are connected in series; and / or, the protection circuit is connected to the P-phase circuit; and / or, an inductor L is provided on the P-phase circuit; and the inductor L is located upstream of the connection circuit.

[0009] Furthermore, the comparison circuit includes: a current sensor located downstream of the connection circuit; the current sensor is arranged on the N-phase circuit; a comparator, the comparator is connected to the current sensor; and the comparator outputs a comparison signal according to the current transmitted by the current sensor.

[0010] Furthermore, the comparison circuit includes: a capacitor C3, one end of the capacitor C3 is connected to the circuit between the current sensor and the comparator, and the other end of the capacitor C3 is grounded.

[0011] Furthermore, the comparison circuit includes a 555 timer, the 555 timer is connected to the output end of the comparator, and the 555 timer sends the comparison signal output by the comparator to the protection circuit.

[0012] Furthermore, the protection circuit includes: a driving circuit, the driving circuit is used to control the switch K1 to be closed or opened; and a driving module, the driving module is connected to the driving circuit to control the on and off of the driving circuit according to the comparison signal.

[0013] Furthermore, the driving circuit includes: a MOS tube, a gate of the MOS tube is connected to the driving module; a source of the MOS tube is connected to the control circuit, and a drain of the MOS tube is connected to the driving circuit.

[0014] Furthermore, the driving module comprises: a triode, the base of the triode is connected to the comparison circuit; the emitter of the triode is connected to the gate of the MOS tube.

[0015] Furthermore, the inverter structure also includes: resistors R3 and R4, which are connected in series with the emitter of the transistor in sequence, and the circuit between resistors R3 and R4 is connected to the gate of the MOS tube; capacitor C2, which is connected in parallel with resistor R4.

[0016] Furthermore, the inverter structure also includes: a resistor R1, which is connected in series with the gate of the MOS tube; a resistor R2, which is connected in series with the drain of the MOS tube; a driving circuit connected to the circuit between the resistor R2 and the drain of the MOS tube; and a capacitor C1, which is connected in parallel with the resistor R2.

[0017] A control method is applicable to the above-mentioned inverter structure, and the control method includes: the control circuit is powered on to operate the inverter component; the comparison circuit detects the current on the control circuit, and the comparison circuit detects whether the current on the control circuit is overcurrent; if overcurrent, a first signal is transmitted to the protection circuit to make the protection circuit shut down the control circuit; if not overcurrent, a second signal is transmitted to the protection circuit to make the protection circuit not shut down the control circuit.

[0018] Beneficial effects:

[0019] The inverter structure of the present invention includes a control circuit, on which an inverter component and a control switch K for controlling the output or shutdown of the inverter component are arranged; a comparison circuit, which is connected to the control circuit to receive the current on the control circuit; a protection circuit, which is connected to the control circuit signal; the comparison circuit outputs a signal to the protection circuit according to the received current on the control circuit; the protection circuit controls the control switch K to close or open according to the signal output by the comparison circuit. With the above arrangement, the connection between the power supply side and the inverter side can be directly disconnected through the over-protection circuit, thereby protecting the inverter module and the compressor side at the same time. They all play an over-current protection role, achieving the purpose of responding to over-current protection more quickly and efficiently. Responding to over-current protection by hardware means (relay K shutdown control) is faster and more efficient than the traditional sampling control software means, and solves the technical problem that the inverter is easily damaged. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic structural diagram of an inverter structure used in an embodiment of the present invention when overcurrent occurs;

[0021] Figure 2 is a structural schematic diagram of the inverter structure adopted in the embodiment of the present invention when it is working normally;

[0022] Figure 3 It is a flow chart of the control method adopted in the embodiment of the present invention.

[0023] The above drawings include the following reference numerals:

[0024] 1. Control circuit; 11. P-phase circuit; 12. N-phase circuit; 13. Connection circuit; 2. Inverter component; 3. Comparison circuit; 31. Current sensor; 32. Comparator; 33. 555 timer; 4. Protection circuit; 41. Drive circuit; 42. Drive module. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0026] See also Figures 1 to 3According to an embodiment of the present invention, an inverter structure is provided, including: a control circuit 1, on which an inverter component 2 and a control switch K1 for controlling the output or shutdown of the inverter component 2 are arranged; a comparison circuit 3, which is connected to the control circuit 1 to receive the current on the control circuit 1; a protection circuit 4, which is connected to the control circuit 1 signal; the comparison circuit 3 outputs a signal to the protection circuit 4 according to the received current on the control circuit 1; the protection circuit 4 controls the control switch K1 to close or open according to the signal output by the comparison circuit 3. With the above arrangement, the connection between the power supply side and the inverter side can be directly disconnected through the over-protection circuit 4, protecting the inverter module and the compressor side at the same time. They all play an over-current protection role, achieving the purpose of responding to over-current protection more quickly and efficiently. Responding to over-current protection by hardware means (relay K1 shutdown control) is faster and more efficient than the traditional sampling control software means, solving the technical problem that the inverter is easily damaged.

[0027] In the inverter structure of this embodiment, see Figure 1 , Figure 2 The control circuit 1 includes: a P-phase circuit 11 connected to the inverter component 2; an N-phase circuit 12 connected to the inverter component 2; a comparison circuit 3 connected to the N-phase circuit 12; a connection circuit 13, one end of the connection circuit 13 is connected to the P-phase circuit 11, and the other end of the connection circuit 13 is connected to the N-phase circuit 12; a capacitor is provided on the connection circuit 13. In this way, by providing the capacitor, the alternating current on the control circuit 1 passes through the capacitor, thereby playing a filtering role, which facilitates the comparison circuit 3 to generate a signal.

[0028] See also Figure 1 , Figure 2 In the inverter structure of this embodiment, there are multiple capacitors, and the multiple capacitors are connected in series; this is beneficial to improving the filtering effect.

[0029] The protection circuit 4 is connected to the P-phase circuit 11. In the inverter structure of this embodiment, see Figure 1 , Figure 2 In this way, the protection circuit 4 draws power from the control circuit 1, simplifying the circuit structure.

[0030] See also Figure 1 , Figure 2 , an inductor L is provided on the P-phase circuit 11 ; the inductor L is located upstream of the connecting circuit 13 .

[0031] See also Figure 1 , Figure 2In the inverter structure of this embodiment, the comparison circuit 3 includes: a current sensor 31, which is located downstream of the connection circuit 13; the current sensor 31 is arranged on the N-phase circuit 12; a comparator 32, which is connected to the current sensor 31; and the comparator 32 outputs a comparison signal according to the current transmitted by the current sensor 31. In this way, the current outputs a corresponding voltage value through the current sensor 31, and the comparator determines whether there is an overcurrent according to the corresponding voltage value output by the current sensor 31, thereby outputting different signals.

[0032] In the inverter structure of this embodiment, see Figure 1 , Figure 2 The comparison circuit 3 includes a capacitor C3, one end of which is connected to the circuit between the current sensor 31 and the comparator 32, and the other end of which is grounded. In this way, the signal input to the comparator 32 is filtered to ensure the accuracy of the input signal.

[0033] See also Figure 1 , Figure 2 In the inverter structure of this embodiment, the comparison circuit 3 includes a 555 timer 33, which is connected to the output end of the comparator 32, and the 555 timer 33 sends the comparison signal output by the comparator to the protection circuit 4. In this way, the function of the 555 timer is to make FO remain at a low level for a period of time when an overcurrent is triggered, so as to ensure that the capacitor is discharged completely within this period of time.

[0034] In the inverter structure of this embodiment, see Figure 1 , Figure 2 The protection circuit 4 includes: a driving circuit 41, which is used to control the switch K1 to be closed or opened; and a driving module 42, which is connected to the driving circuit 41 to control the on and off of the driving circuit 41 according to the comparison signal. In this way, a signal can be converted into the action of controlling the switch K1, so that the control is faster.

[0035] See also Figure 1 , Figure 2 In the inverter structure of this embodiment, the driving circuit 41 includes: a MOS tube, the gate of the MOS tube is connected to the driving module 42; the source of the MOS tube is connected to the control circuit 1, and the drain of the MOS tube is connected to the driving circuit 41. In this way, the driving circuit 41 can be powered on or off by comparing the signal, thereby controlling whether the switch is disconnected.

[0036] In the inverter structure of this embodiment, see Figure 1 , Figure 2The driving module 42 includes a transistor, the base of which is connected to the comparison circuit 3; the emitter of which is connected to the gate of the MOS tube. By setting the transistor, it is determined what type of signal is transmitted from the comparison circuit 2, thereby triggering the transistor to be powered on or off, and then controlling whether the switch K1 is disconnected.

[0037] See also Figure 1 , Figure 2 In the inverter structure of this embodiment, the inverter structure also includes: resistors R3 and R4, which are connected in series with the emitter of the triode, and the circuit between the resistors R3 and R4 is connected to the gate of the MOS tube; capacitor C2 is connected in parallel with the resistor R4. In this way, the voltage division of the resistors R3 and R4 is used to provide a suitable signal for the MOS tube.

[0038] In the inverter structure of this embodiment, see Figure 1 , Figure 2 The inverter structure also includes: a resistor R1, which is connected in series with the gate of the MOS tube; a resistor R2, which is connected in series with the drain of the MOS tube; a drive circuit 41 connected to the circuit between the resistor R2 and the drain of the MOS tube; and a capacitor C1, which is connected in parallel with the resistor R2. In this way, the resistors R1 and R2 divide the voltage to provide a suitable voltage for the drive circuit 41, thereby accurately controlling the switch K1.

[0039] See also Figure 3 The control method of this embodiment is applicable to the above-mentioned inverter structure, and the control method includes: the control circuit 1 is powered on to operate the inverter component 2; the comparison circuit 3 detects the current on the control circuit 1, and the comparison circuit 3 detects whether the current on the control circuit 1 is overcurrent; if it is overcurrent, a first signal is transmitted to the protection circuit 4 to make the protection circuit 4 shut down the control circuit 1; if it is not overcurrent, a second signal is transmitted to the protection circuit 4 to make the protection circuit 4 not shut down the control circuit 1.

[0040] By adopting the above method, the connection between the power supply side and the inverter side can be directly disconnected through the over-protection circuit, protecting the inverter module and the compressor side at the same time. Both play an over-current protection role, achieving the purpose of responding to over-current protection more quickly and efficiently. Responding to over-current protection by hardware means (relay K shutdown control) is faster and more efficient than the traditional sampling control software means, solving the technical problem that the inverter is easily damaged.

[0041] Embodiment 1:

[0042] When the driver board operates normally and does not exceed the set current protection value, the current outputs a corresponding voltage value through the current sensor 31. At this time, when the output voltage value is less than the set reference voltage protection value U2, the desired set value is obtained through the voltage division of resistors R5 and R6, that is, U0<U2. A high level signal is output through the comparator, and then a high level signal is output through the 555 timer. At this time, FO is high level, the transistor Q1 is turned on, and the capacitor C2 is charged. According to the voltage division of R3 and R4, U1 obtains the conduction voltage drop voltage to turn on the MOS tube. The DC bus P obtains a voltage of about 12V through the voltage division of R1 and R2 to drive the relay K1 to attract, and the driver board operates normally.

[0043] When a large current appears during operation, the current sensor outputs the corresponding voltage value. At this time, the output voltage value is greater than the set reference voltage protection value U2, that is, U0>U2. The comparator outputs a low-level signal, and then the 555 timer outputs a low-level signal. At this time, FO is a low-level signal, the transistor Q1 is cut off, the MOS tube is turned off, the C1 capacitor discharges to R2 instantly, the C1 capacitor voltage drops to 0, and no current passes through the relay K1. The relay is disconnected, the loop is disconnected, and the purpose of overcurrent protection of the circuit is achieved. This overcurrent protection method not only ensures that the inverter module side can be quickly protected, but also plays a role in rapid response protection for the power supply side when K1 is disconnected.

[0044] The role of the 555 timer here is to make FO remain low for a period of time when an overcurrent is triggered, ensuring that the capacitor is discharged within this period of time.

[0045] When the driver board operates normally, that is, when the transistor Q1 and the MOS are turned on, the resistor R4 is a voltage divider resistor and plays a role of voltage division; when the overcurrent is triggered, R4 acts as a discharge resistor and plays a role of rapid discharge of the capacitor C2, which is one of the means of faster response protection.

[0046] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0047] Optionally, the specific examples in this embodiment may refer to the examples described in the above embodiments, and this embodiment will not be described in detail here.

[0048] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0049] In the above embodiments of the present application, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0050] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. An inverter structure, characterized in that: include: A control circuit (1), wherein the control circuit (1) is provided with an inverter component (2) and a control switch K1 for controlling the inverter component (2) to output or shut down; A comparison circuit (3), the comparison circuit (3) being connected to the control circuit (1) to receive a current on the control circuit (1); A protection circuit (4), wherein the protection circuit (4) is signal-connected to the control circuit (1); the comparison circuit (3) outputs a signal to the protection circuit (4) according to the current received from the control circuit (1); and the protection circuit (4) controls the control switch K1 to close or open according to the signal output by the comparison circuit (3).

2. The inverter structure according to claim 1, characterized in that: The control circuit (1) comprises: A P-phase circuit (11) connected to the inverter component (2); An N-phase circuit (12) is connected to the inverter component (2); the comparison circuit (3) is connected to the N-phase circuit (12); A connecting circuit (13), one end of the connecting circuit (13) is connected to the P-phase circuit (11), and the other end of the connecting circuit (13) is connected to the N-phase circuit (12); a capacitor is provided on the connecting circuit (13).

3. The inverter structure according to claim 2, characterized in that: There are multiple capacitors, and the multiple capacitors are connected in series; and / or, The protection circuit (4) is connected to the P-phase circuit (11); and / or, The P-phase circuit (11) is provided with an inductor L; the inductor L is located upstream of the connecting circuit (13).

4. The inverter structure according to claim 2, characterized in that: The comparison circuit (3) comprises: a current sensor (31), located downstream of the connection circuit (13); the current sensor (31) is arranged on the N-phase circuit (12); A comparator (32), the comparator (32) being connected to the current sensor (31); the comparator (32) outputs a comparison signal according to the current transmitted by the current sensor (31).

5. The inverter structure according to claim 4, characterized in that: The comparison circuit (3) comprises: A capacitor C3, one end of which is connected to the circuit between the current sensor (31) and the comparator (32), and the other end of which is grounded.

6. The inverter structure according to claim 4, characterized in that: The comparison circuit (3) comprises a 555 timer (33), the 555 timer (33) is connected to the output end of the comparator (32), and the 555 timer (33) sends the comparison signal output by the comparator to the protection circuit (4).

7. The inverter structure according to claim 1, characterized in that: The protection circuit (4) comprises: A drive circuit (41), the drive circuit (41) is used to control the switch K1 to be closed or opened; A driving module (42), the driving module (42) being connected to the driving circuit (41) to control the on and off of the driving circuit (41) according to the comparison signal.

8. The inverter structure according to claim 7, characterized in that: The driving circuit (41) comprises: A MOS tube, wherein the gate of the MOS tube is connected to the driving module (42); the source of the MOS tube is connected to the control circuit (1); and the drain of the MOS tube is connected to the driving circuit (41).

9. The inverter structure according to claim 8, characterized in that: The driving module (42) comprises: A triode, the base of which is connected to the comparison circuit (3); the emitter of which is connected to the gate of the MOS tube.

10. The inverter structure according to claim 9, characterized in that: The inverter structure also includes: Resistors R3 and R4, wherein the resistors R3 and R4 are connected in series with the emitter of the transistor in sequence, and the circuit between the resistors R3 and R4 is connected to the gate of the MOS tube; Capacitor C2 is connected in parallel with resistor R4.

11. The inverter structure according to claim 9, characterized in that: The inverter structure further includes: A resistor R1, wherein the resistor R1 is connected in series with the gate of the MOS tube; A resistor R2, the resistor R2 being connected in series with the drain of the MOS tube; the drive circuit (41) being connected to the circuit between the resistor R2 and the drain of the MOS tube; Capacitor C1, the capacitor C1 is connected in parallel with the resistor R2.

12. A control method, applicable to the inverter structure according to any one of claims 1 to 11, characterized in that: The control method comprises: The control circuit (1) is powered on to operate the inverter component (2); The comparison circuit (3) detects the current on the control circuit (1), and the comparison circuit (3) detects whether the current on the control circuit (1) is overcurrent; If there is an overcurrent, a first signal is transmitted to the protection circuit (4) so ​​that the protection circuit (4) turns off the control circuit (1); If there is no overcurrent, a second signal is transmitted to the protection circuit (4) so ​​that the protection circuit (4) does not shut down the control circuit (1).

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