Variable frequency driving system with energy recovery function for central air conditioner

Abstract

The utility model discloses a frequency conversion driving system with an energy recovery function for a central air conditioner, comprising a rectification assembly comprising an RBR / S / T thyristor and a thyristor driving IR / S / T driving board, and the RBR / S / T thyristor is connected with the thyristor driving IR / S / T driving board in a three-phase half-control rectification mode and is used for converting input commercial power AC voltage into DC voltage; in the capability recovery link, the DC / AC transformation module is divided into two parts, namely an IL module and an IN module; the public energy storage link is bridged behind the rectification assembly and comprises N capacitors C1 to CN which are connected in series; and each inversion assembly comprises three IU / V / WIGBT modules and three IU / V / WQ driving boards, and each IU / V / WIGBT module is directly connected with one IU / V / WQ driving board to form an inversion bridge. Low-voltage charging is provided in the charging process, which is safer and more reliable; and inertia energy of the motor can be recycled under emergency power failure, the energy utilization rate is improved, and environmental protection is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of frequency conversion, in particular to a frequency conversion drive system with an energy recovery function for a central air conditioner. Background Art

[0002] With economic development, environmental issues are receiving increasing attention. To conserve energy, reduce emissions, and achieve greater energy efficiency, central air conditioners are increasingly adopting variable-frequency drives (VFDs). With the increasing use of VFDs, the issue of energy recovery and reuse has been frequently raised in recent years. While VFDs improve energy efficiency, regional power outages and price discrepancies persist. Given the current surge in demand for energy recovery and reuse, VFDs require energy regeneration capabilities.

[0003] Existing energy feedback systems using four-quadrant inverters are as follows Figure 1 , contains the following parts:

[0004] Mains power grid, circuit breaker QF1, LCL filter components, PEM finishing, filter capacitor C, inverter IGBT, motor;

[0005] The existing solution has the following problems:

[0006] This solution is designed with LCL filter components, and the IGBT cabinet used for rectification is large in size and high in cost;

[0007] The feedback energy of this solution is directly input into the power grid. Although energy feedback can be achieved, the recovered energy cannot be reused. Utility Model Content

[0008] The technical problem to be solved by the present invention is that the IGBT cabinets used in the existing four-quadrant inverter system are large in size, high in cost, and cannot reuse the recovered energy. The present invention provides a variable frequency drive system with energy recovery function for central air conditioning. The system can realize energy feedback by charging the microgrid and powering emergency lighting equipment through the DC / AC transformer module. In the event of an emergency power outage, the motor inertia energy can be recovered to improve energy utilization. Low voltage charging is provided during the charging process, which is safer and more reliable. A low-pass filter is formed by an inductor and a capacitor at the output end to make the output current more in line with the electricity consumption standard.

[0009] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0010] A variable frequency drive system with energy recovery function for a central air conditioner, characterized by comprising:

[0011] A rectifier assembly: including RBR / S / T thyristors and a thyristor driver IR / S / T driver board, the RBR / S / T thyristors are connected to the thyristor driver IR / S / T driver board through a three-phase half-controlled rectification method, and are used to convert the input AC voltage of the mains into a DC voltage;

[0012] A capacity recovery link: DC / AC transformer module, divided into two parts: IL module and IN module;

[0013] A public energy storage link: connected across the rectifier component, including N capacitors C1 to CN connected in series;

[0014] Inverter components, each inverter component includes three IU / V / WIGBT modules and three IU / V / WQ driver boards. Each IU / V / WIGBT module is directly connected to an IU / V / WQ driver board to form an inverter bridge.

[0015] In the above technical solution, the DC / AC transformer module includes: an IL / NQ driver board, an IL / NIGBT module, an LT Hall sensor, and an IL / NC absorption capacitor. The IL / NQ driver board is directly connected to the IL / NIGBT module, the IL / NC absorption capacitor is connected across the P and N terminals of the IL / NIGBT module, and the output port OUT of the IL / NIGBT module is connected to the LT Hall sensor.

[0016] The negative pole P- on the left side of the DC / AC transformer module is connected to the negative pole of the C1~N capacitor, the L on the right side is connected to the L port of the microgrid and the L port of the emergency lighting equipment, and the N on the right side is connected to the N port of the microgrid and the N port of the emergency lighting equipment.

[0017] In the above technical solution, the inverter component includes a U / V / WCT Hall sensor, an IU / V / WC absorption capacitor and a PM01 motor. The IU / V / WC absorption capacitor is connected between P and N of the IU / V / WIGBT module, and the output port OUT of the IU / V / WIGBT module is connected to the PM01 motor through the U / V / WCT Hall sensor.

[0018] In the above technical solution, a first control board is provided, and the first control board is respectively connected to the thyristor driver IR / S / T driver board, the IU / V / WQ driver board, and the U / V / WCT Hall sensor.

[0019] In the above technical solution, a second control board is provided, and the second control board is connected to the IL / NQ driving board and the LT Hall sensor respectively.

[0020] In the above technical solution, the positive electrode of the C1~N capacitor is connected to the input terminal P of the IU / V / WIGBT module and the output port 2 of the RBR / S / T thyristor, the negative electrode of the C1~N capacitor is connected to the input terminal N of the IU / V / WIGBT module and the output port 1 of the RBR / S / T thyristor, and the RVS voltage-equalizing resistor is connected between the positive and negative electrodes of the C1~N capacitor.

[0021] In the above technical solution, in the rectifier assembly, the thyristor driver IR / vS / T driver board is connected to the K1 / G1 port of the RBR / S / T thyristor.

[0022] In the above technical solution, a semiconductor protection fuse is set on the lead-out line between the rectifier component and the energy recovery link. The right side of the semiconductor protection fuse is connected to the left positive pole P of the DC / AC transformer module, and the left side of the semiconductor protection fuse is connected to the positive poles of capacitors C1~CN.

[0023] In the above technical solution, a set of two series filter inductors is provided in the DC / AC transformer module. The left end of the series filter inductor passes through the LT Hall sensor and is connected to the IL / NIGBT module output port OUT, and the right end of the series filter inductor is connected to the output terminal L.

[0024] In the above technical solution, a filter capacitor is set in the DC / AC transformer module, the positive electrode of the filter capacitor is connected to the middle of the two series inductors, and the negative electrode of the filter capacitor is connected to the IN module output port OUT and the input terminal N.

[0025] The working principle of this utility model is as follows:

[0026] When the utility power goes out, the first control board detects the grid outage and controls the IU / V / WQ driver board to turn on the IU / V / W IGBT module to continue providing voltage to the motor stator. In this process, the voltage frequency is reduced and the stator frequency is adjusted to be lower than the rotor frequency, so that the motor runs in the generator state, maintaining the voltage of the filter capacitor energy storage link stable at 540V, and continuously supplying power to the DC / AC transformer module. The DC / AC transformer module outputs a sinusoidal 220V / 50Hz power supply, which is stably provided to the microgrid and emergency lighting equipment.

[0027] In this solution, the FU1 semiconductor protection fuse serves as short-circuit protection.

[0028] Compared with the prior art, the beneficial effects produced by the present invention are:

[0029] 1. The system of this utility model realizes the slow rise of DC bus voltage through half-controlled rectification and provides low-voltage charging during the charging process, which is safer and more reliable.

[0030] 2. The utility model is designed with an energy recovery device, which can recover the motor inertia energy in the event of an emergency power outage, improve energy utilization and achieve environmental protection.

[0031] 3. The system of this utility model uses DC / AC transformer module to replace IGBT rectifier for energy feedback, which has low cost, small cabinet size and better recovery rate.

[0032] 4. The utility model system is designed with an output inductor and capacitor to form a low-pass filter to make the output waveform closer to a sine wave and more in line with electricity standards;

[0033] 5. The system design of this utility model uses fuse FU1 to provide short-circuit protection for the DC circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0035] Figure 1 This is a four-quadrant inverter system diagram.

[0036] Figure 2 This is a diagram of a variable frequency drive system with energy recovery function for central air conditioning.

[0037] Figure 3 Schematic diagram of RBR / S / T thyristor.

[0038] Figure 4 This is a schematic diagram of the IU / V / WIGBT module.

[0039] Figure 5 This is a schematic diagram of the DC / AC transformer module. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0041] like Figure 2-5 As shown, a dual-charging energy storage variable frequency drive system for central air conditioning implemented according to the present invention includes the following four links:

[0042] Rectification 100: RBR / S / T thyristor 4 is configured with thyristor drive IR / S / T driver board 3, using three-phase half-controlled rectification to convert input AC power into DC. When powered on, the half-controlled rectification circuit controls the output voltage to rise slowly. When the mains power grid 30 is charged, the DC voltage is adjusted to low voltage to charge the external energy storage link (200);

[0043] Energy recovery link 200: charging the microgrid 31 battery array and emergency lighting equipment 32 through the DC / AC transformer module;

[0044] Public energy storage link: When C1~N capacitor 5 is powered on, it first undergoes half-controlled rectification before reaching capacitor C. The bus voltage rises slowly. The capacitor filters the DC voltage and supports the operation of the subsequent inverter.

[0045] Inverter 300: The IU / V / WIGBT module 13 and the IU / V / WQ driver board 12 form an inverter network. Under the control of the first control board 16, the DC power is output as frequency-adjustable AC power to the U, V, and W terminals, and then output to the PM01 motor from the U / V / W terminals.

[0046] QF1 circuit breaker 1, L reactor 2, thyristor driver IR / S / T driver board 3, RBR / S / T thyristor 4, C1~N capacitors 5, RVS voltage-equalizing resistor 6, PM01 motor 7, FU1 semiconductor protection fuse 8, copper busbar 9, control cable 10, first control board 11, IU / V / WQ driver board 12, IU / V / WIGBT module 13, U / V / WCT Hall sensor 14, IU / V / WC absorption capacitor 15, incoming line filter inductor 16, series filter inductor left end inductor 17, series filter inductor right end inductor 18, KM1 contactor 19, RES1 starting resistor 20, second control board 21, first filter capacitor 22, IL / NQ driver board 23, IL / NIGBT module 24, LT Hall sensor 25, IL / NC absorption capacitor 26, second filter capacitor 27;

[0047] Other components do not belong to the system and are used to illustrate the solution: mains power grid 30 , microgrid 31 , emergency lighting equipment 32 .

[0048] The right end of QF1 circuit breaker 1 is connected to port 1 of RBR / S / T thyristor 4 using copper busbar 9, as shown in Figure 2 and 3 ;

[0049] The left end of the QF1 circuit breaker 1 is connected to the mains power grid 30 using a copper bus 9. Figure 2 ;

[0050] The output port 2 of the RBR / S / T thyristor 4 is connected to the positive electrode of the C1~N capacitor 5 through the copper bus 9; Figure 2 and 3 ;

[0051] The output port 1 of the RBR / S / T thyristor 4 is connected to the negative electrode of the C1~N capacitor 5 through the copper bus 9; Figure 2 and 3 ;

[0052] The thyristor driver IR / vS / T driver board 3 is connected to the K1 / G1 port of the RBR / S / T thyristor 4 via the control cable 10, as shown in FIG. Figure 2 ;

[0053] RVS voltage grading resistor 6 is connected across the positive and negative terminals of C1~N capacitor 5, such as Figure 2 ;

[0054] The positive electrode of the C1~N capacitor 5 is connected to the input terminal P of the IU / V / WIGBT module 13 through the copper bus 9, as shown in FIG. Figure 2 and 4 ;

[0055] The negative electrode of the C1~N capacitor 5 is connected to the input terminal N of the IU / V / WIGBT module 13 through the copper bus 9, as shown in FIG. Figure 2 and 4 ;

[0056] The IU / V / WQ driver board 12 is directly connected to the IU / V / WIGBT module 13, and the IGBT driver board pads are soldered to the IGBT contacts. Figure 2 ;

[0057] The IU / V / WC absorption capacitor 15 is connected between the P and N terminals of the IU / V / WIGBT module 13. Figure 2 ;

[0058] The first control board 11 is connected to the thyristor drive IR / S / T drive board 3, the IU / V / WQ drive board 12, and the U / V / WCT Hall sensor 14 through the control cable 10. Figure 2 ;

[0059] The output port OUT of the IU / V / WIGBT module 13 is connected to the PM01 motor 7 through the copper bus 18 through the U / V / WCT Hall sensor 14, as shown in FIG. Figure 2 ;

[0060] The left positive electrode P of the DC / AC transformer module 200 is connected to the right side of the FU1 semiconductor protection fuse 8, as shown in FIG. Figure 2 ;

[0061] The left side of FU1 semiconductor protection fuse 8 is connected to the positive electrode of C1~N capacitor 5, such as Figure 2 ;

[0062] The left negative electrode P- of the DC / AC transformer module 200 is connected to the negative electrode of the C1~N capacitor 5, as shown in FIG. Figure 2 ;

[0063] The right side L of the DC / AC transformer module 200 is connected to the L port of the microgrid 31, as shown in FIG. Figure 2 ;

[0064] The right side N of the DC / AC transformer module 200 is connected to the N port of the microgrid 31, as shown in FIG. Figure 2 ;

[0065] The right side L of the DC / AC transformer module 200 is connected to the L port of the emergency lighting device 32, such as Figure 2 ;

[0066] The right N of the DC / AC transformer module 200 is connected to the N port of the emergency lighting device 32, such as Figure 2 ;

[0067] The internal structure of the DC / AC transformer module 200 is as follows: Figure 5 As shown;

[0068] The right end of the inlet filter inductor 16 is connected to the left end of the KM1 contactor 19 using a copper bus 9, as shown in Figure 5 ;

[0069] The left end of the inlet filter inductor 16 is connected to the positive electrode of the C1~N capacitor 5 using a copper bus 9, as shown in Figure 2 ;

[0070] The right end of the KM1 contactor 19 is connected to the positive electrode of the first filter capacitor 22 through the copper bus 9, as shown in FIG. Figure 5 ;

[0071] The P-port of the negative electrode of the C1~N capacitor 5 is connected to the negative electrode of the first filter capacitor 22 through the copper bus 9, as shown in FIG. Figure 2 ;

[0072] The positive electrode of the first filter capacitor 22 is connected to the input terminal P of the IL / NIGBT module 24 through the copper bus 9. Figure 4 and 5 ;

[0073] The negative electrode of the first filter capacitor 22 is connected to the input terminal N of the IL / NIGBT module 24 through the copper bus 9. Figure 4 and 5 ;

[0074] The IL / NQ driver board 23 is directly connected to the IL / NIGBT module 24, and the IGBT driver board pads are soldered to the IGBT contacts. Figure 2 ;

[0075] The IL / NC absorption capacitor 26 is connected across the P and N terminals of the IL / NIGBT module 24. Figure 5 ;

[0076] The second control board 17 is connected to the IL / NQ driver board 23 and the LT Hall sensor 25 through the control line 10. Figure 5 ;

[0077] The output port OUT of the IL module 24 is connected to the left end of the series filter inductor 17 through the copper bus 9 and the LT Hall sensor 25;

[0078] The left end of the series filter inductor and the right end of the inductor 17 are respectively connected to the left end of the right end of the series filter inductor 18 and the left side of the second filter capacitor 27, as shown in FIG. Figure 5 As shown;

[0079] The output port OUT of the IN module 24 is connected to the right side of the second filter capacitor 27 and the output terminal N through the copper bus 9. Figure 5 As shown;

[0080] The right end of the series filter inductor 18 is connected to the output terminal L, as shown in Figure 5 As shown;

[0081] The undescribed parts involved in the present invention are the same as the existing technology or are implemented by using the existing technology.

[0082] In summary, the present invention has the following key technical points:

[0083] 1. This system uses a DC / AC transformer module to replace the IGBT rectifier for energy feedback. The DC / AC transformer module is used to charge the microgrid and power emergency lighting equipment to achieve energy feedback. This has low cost, small cabinet size, and better recovery rate.

[0084] 2. This system design uses fuse FU1 to provide short-circuit protection for the DC circuit;

[0085] 3. This system is designed to use half-controlled rectification, the voltage rises slowly during the charging time, and provides low-voltage charging during the charging process to prevent the device from being damaged by surge voltage.

[0086] 4. The output end of this system is designed to consist of a low-pass filter composed of inductors and capacitors, so that the output waveform is closer to a sine wave and more in line with electricity standards.

[0087] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all such improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A variable frequency drive system with energy recovery function for central air conditioning, characterized in that include: A rectifier assembly: including RBR / S / T thyristors and a thyristor driver IR / S / T driver board, the RBR / S / T thyristors are connected to the thyristor driver IR / S / T driver board through a three-phase half-controlled rectification method; A capacity recovery link: DC / AC transformer module, divided into two parts: IL module and IN module; A public energy storage link: connected across the rectifier component, including N capacitors C1 to CN connected in series; Inverter components, each inverter component includes three IU / V / WIGBT modules and three IU / V / WQ driver boards. Each IU / V / WIGBT module is directly connected to an IU / V / WQ driver board to form an inverter bridge.

2. The variable frequency drive system with energy recovery function for central air conditioning according to claim 1, characterized in that: The DC / AC transformer module includes: an IL / NQ driver board, an IL / NIGBT module, an LT Hall sensor, and an IL / NC absorption capacitor. The IL / NQ driver board is directly connected to the IL / NIGBT module. The IL / NC absorption capacitor is connected across the P and N terminals of the IL / NIGBT module. The OUT port of the IL / NIGBT module is connected to the LT Hall sensor. The negative pole P- on the left side of the DC / AC transformer module is connected to the negative pole of the C1~N capacitor, the L on the right side is connected to the L port of the microgrid and the L port of the emergency lighting equipment, and the N on the right side is connected to the N port of the microgrid and the N port of the emergency lighting equipment.

3. The variable frequency drive system with energy recovery function for central air conditioning according to claim 1, characterized in that: The inverter component includes a U / V / WCT Hall sensor, an IU / V / WC absorption capacitor and a PM01 motor. The IU / V / WC absorption capacitor is connected between P and N of the IU / V / WIGBT module. The output port OUT of the IU / V / WIGBT module is connected to the PM01 motor through the U / V / WCT Hall sensor.

4. The variable frequency drive system with energy recovery function for central air conditioning according to claim 3, characterized in that: A first control board is provided, and the first control board is connected to the thyristor drive IR / S / T drive board, the IU / V / WQ drive board, and the U / V / WCT Hall sensor respectively.

5. The variable frequency drive system with energy recovery function for central air conditioning according to claim 2, characterized in that: A second control board is provided, and the second control board is connected to the IL / NQ driving board and the LT Hall sensor respectively.

6. The variable frequency drive system with energy recovery function for central air conditioning according to claim 1, characterized in that: The positive electrode of the C1~N capacitor is connected to the input terminal P of the IU / V / WIGBT module and the output port 2 of the RBR / S / T thyristor, and the negative electrode of the C1~N capacitor is connected to the input terminal N of the IU / V / WIGBT module and the output port 1 of the RBR / S / T thyristor.

7. The variable frequency drive system with energy recovery function for central air conditioning according to claim 1, characterized in that: In the rectifier assembly, the thyristor driver IR / vS / T driver board is connected to the K1 / G1 port of the RBR / S / T thyristor.

8. The variable frequency drive system with energy recovery function for central air conditioning according to claim 1, characterized in that: A semiconductor protection fuse is set on the lead-out line between the rectifier component and the energy recovery link. The right side of the semiconductor protection fuse is connected to the left positive pole P of the DC / AC transformer module, and the left side of the semiconductor protection fuse is connected to the positive poles of capacitors C1~CN.

9. The variable frequency drive system with energy recovery function for central air conditioning according to claim 2, characterized in that: A set of two series filter inductors is provided in the DC / AC transformer module. The left end of the series filter inductor group is connected to the IL / NIGBT module output port OUT through the LT Hall sensor, and the right end of the series filter inductor group is connected to the output terminal L.

10. The variable frequency drive system with energy recovery function for central air conditioning according to claim 9, characterized in that: A filter capacitor is provided in the DC / AC transformer module, the positive electrode of the filter capacitor is connected to the middle of the two series inductors, and the negative electrode of the filter capacitor is connected to the output port OUT and the input terminal N of the IN module.

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