Pre-charging device of high-voltage direct-current electric scroll compressor

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By designing a precharge device in a high-voltage DC electric scroll compressor, using components such as high-voltage DC relays, capacitors and fuses, the impact current problem during the moment of power-on on the high-voltage DC electric scroll compressor is solved, and the safety and reliability of the equipment are improved.

CN120466201APending Publication Date: 2025-08-12HEFEI SWAN REFRIGERATOR TECH CO LTD

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Patent Information

Application Number: CN202510859049.0
Authority / Receiving Office: CN · China
Patent Type: Applications(China)
Current Assignee / Owner
Filing Date: 2025-06-25
Publication Date: 2025-08-12

AI Technical Summary

Technical Problem

The instantaneous impulse current at the moment when powering on a high-voltage DC electric scroll compressor will cause damage to the power supply main circuit, and the prior art lacks effective precharge devices to prevent such problems.

Method used

Design a pre-charge device including high-voltage DC relay, capacitor, freewheeling diode and high-voltage DC fuse. By establishing a bus voltage before the high-voltage DC electric scroll compressor is operated, it prevents instantaneous impingement current, uses a G-type fuse to provide full current protection, uses a polarity-free film capacitor to increase the life of the capacitor, and sets a freewheeling diode to provide an energy drain circuit for the high-voltage DC relay coil.

Benefits of technology

It reduces the failure rate, improves reliability in harsh environments, extends service life, ensures the safety of air conditioning equipment and the safety of the entire vehicle, and prevents damage to the main circuit power devices.

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Abstract

The invention discloses a pre-charging device for a high-voltage direct-current electric scroll compressor, which comprises a high-voltage direct-current relay, a capacitor and a fly-wheel diode which are arranged in the same shell, a coil of the high-voltage direct-current relay is accessed to a signal of an external controller, and the pre-charging of the capacitor is controlled through a normally open contact of the relay; dC bus voltage is established through capacitor pre-charging, meanwhile, an energy discharge loop is provided for a high-voltage DC relay coil through a fly-wheel diode, and external connection of the whole device is achieved through an electric connector arranged on the shell. According to the structure, the fault rate is reduced, the service life is prolonged, short circuit of a high-voltage direct-current circuit at the moment that the compressor is powered on can be prevented, and the safety of air conditioning equipment is guaranteed.

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Description

Technical Field

[0001] The invention relates to the field of compressor charging devices, in particular to a high-voltage direct current electric scroll compressor pre-charging device. Background Art

[0002] With the development and application of high-voltage DC drive technology, air conditioning equipment powered by 200V to 900V high-voltage DC power is becoming increasingly important and widespread. The core component of the refrigeration system of these high-voltage DC-powered air conditioners is an advanced high-voltage DC electric scroll compressor. This horizontal structure features an integrated design with the pump, motor, and controller at the front, center, and back. The motor utilizes a rare earth permanent magnet synchronous motor, and the controller housing is integrated with the compressor housing and located above the compressor's intake port, providing excellent heat dissipation.

[0003] Due to the structural form, volume and technical characteristics of the high-voltage DC electric scroll compressor, the controller does not contain a pre-charging circuit. At the moment of power-on, the DC bus is equivalent to a short circuit, and the instantaneous impact current will cause damage to the power components of the main power supply circuit. Therefore, it is necessary to provide a pre-charging device to establish the high-voltage DC bus voltage before the high-voltage DC electric scroll compressor is operated to avoid the problem of instantaneous impact current. Summary of the Invention

[0004] The present invention provides a high-voltage direct current electric scroll compressor pre-charging device to solve the problem of instantaneous impact current when the high-voltage direct current electric scroll compressor is powered on in the prior art.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is: A high-voltage direct current electric scroll compressor pre-charging device, comprising a high-voltage direct current relay (KA1), a high-voltage direct current relay (KA2), a capacitor (C1), a capacitor (C2), a resistor (R1), a resistor (R2), a freewheeling diode (D1), a freewheeling diode (D2), and a high-voltage direct current fuse (FU1); One end of the coil of the high-voltage DC relay (KA1) is connected to a precharge signal output by an external controller, one end of the coil of the high-voltage DC relay (KA2) is connected to a working signal output by the external controller, and the other ends of the coils of the high-voltage DC relay (KA1) and the high-voltage DC relay (KA2) are connected together and then grounded; The freewheeling diode (D1) is connected in reverse parallel to the coil of the high-voltage DC relay (KA1), and the freewheeling diode (D2) is connected in reverse parallel to the coil of the high-voltage DC relay (KA2); One end of the normally open closed contact (KA2-1) of the high-voltage DC relay (KA2) is connected to the positive electrode of the high-voltage DC power supply through the high-voltage DC fuse (FU1), the other end of the normally open closed contact (KA2-1) of the high-voltage DC relay (KA2) is connected to one end of the capacitor (C1), the other end of the capacitor (C1) is connected to one end of the capacitor (C2), the other end of the capacitor (C2) is connected to the negative electrode of the high-voltage DC power supply, and a wire is led between the normally open closed contact (KA2-1) and the capacitor (C1) to connect to the positive power supply terminal of the controller provided with the high-voltage DC electric scroll compressor, and a wire is led between the capacitor (C2) and the negative electrode of the high-voltage DC power supply to connect to the negative power supply terminal of the controller provided with the high-voltage DC electric scroll compressor; The normally open / closed contact (KA1-1) of the high-voltage DC relay (KA1) is connected in series with the resistor (R1) to form a series branch, and the series branch is then connected in parallel with the normally open / closed contact (KA2-1) of the high-voltage DC relay (KA2); One end of the resistor (R2) is connected between the normally open normally closed contact (KA2-1) and the capacitor (C1), and the other end of the resistor R2 is connected to the lead wire between the capacitor (C2) and the negative electrode of the high-voltage DC power supply.

[0006] Furthermore, the high-voltage DC relay (KA1) and the high-voltage DC relay (KA2) are both Class G fuses.

[0007] Furthermore, the capacitor (C1) and the capacitor (C2) are non-polar film capacitors.

[0008] Furthermore, the resistor (R1) is a power resistor.

[0009] Furthermore, the high-voltage DC relay (KA1), the high-voltage DC relay (KA2), the capacitor (C1), the capacitor (C2), the resistor (R1), the resistor (R2), the freewheeling diode (D1), the freewheeling diode (D2), and the high-voltage DC fuse (FU1) are arranged in the same housing, and a plurality of electrical connectors are provided on the housing, and the plurality of electrical connectors are respectively used to connect an external controller, a high-voltage DC power supply, and a controller provided with the high-voltage DC electric scroll compressor.

[0010] Compared with the prior art, the present invention has the following advantages: 1. The structural form, material, electrical outlet mode and anti-vibration measures of the present invention reduce the failure rate, improve the reliability of working in mountainous, dusty and island reef environments, and extend the service life.

[0011] 2. The present invention uses Class G high-voltage DC fuses to provide full current protection. When the high-voltage DC electric scroll compressor is overloaded or short-circuited, the circuit is quickly cut off and the arc is extinguished, ensuring the safety of the air-conditioning equipment and the entire vehicle.

[0012] 3. The present invention uses non-polar film capacitors to replace polar electrolytic capacitors, which increases the life cycle of the capacitors and their ability to adapt to high and low temperature environments and large ripple currents.

[0013] 4. Before the high-voltage DC electric scroll compressor is put into operation, the present invention establishes the DC bus voltage by precharging the capacitor to prevent the high-voltage DC circuit from short-circuiting when the compressor is powered on, thereby ensuring the safety of the air-conditioning equipment. 5. The present invention is provided with a freewheeling diode to provide an energy discharge circuit for the high-voltage DC relay coil, thereby preventing the peak voltage generated when the coil loses power from being introduced into the DC signal circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural principle diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0015] The present invention will be further described below with reference to the accompanying drawings and examples.

[0016] like Figure 1 As shown, this embodiment discloses a high-voltage DC electric scroll compressor pre-charging device, including a shell, in which a high-voltage DC relay KA1, a high-voltage DC relay KA2, a capacitor C1, a capacitor C2, a resistor R1, a resistor R2, a freewheeling diode D1, a freewheeling diode D2, and a high-voltage DC fuse FU1 are arranged, and electrical connectors XS1.1, XS1.2, XS2.1, XS2.2, XS2.3, XS3.1, and XS3.2 are installed on the side of the shell.

[0017] One end of the coil of HVDC relay KA1 is connected to the precharge signal output by the external air conditioner controller through electrical connector XS2.1. One end of the coil of HVDC relay KA2 is connected to the operating signal output by the external air conditioner controller through electrical connector XS2.2. The other ends of the coils of HVDC relays KA1 and KA2 are connected together and then to ground (GND) through electrical connector XS2.3.

[0018] The freewheeling diode D1 is connected in reverse parallel to the coil of the high-voltage DC relay KA1, that is, the negative end of the freewheeling diode D1 is connected between one end of the coil of the high-voltage DC relay KA1 and the electrical connector XS2.1, and the positive end of the freewheeling diode D1 is connected to the other end of the coil of the high-voltage DC relay KA1; the freewheeling diode D2 is connected in reverse parallel to the coil of the high-voltage DC relay KA2, that is, the negative end of the freewheeling diode D2 is connected between one end of the coil of the high-voltage DC relay KA2 and the electrical connector XS2.2, and the positive end of the freewheeling diode D2 is connected to the other end of the coil of the high-voltage DC relay KA2.

[0019] One end of the normally open closed contact KA2-1 of the high-voltage DC relay KA2 is connected to the positive pole of the high-voltage DC power supply through the high-voltage DC fuse FU1 and the electrical connector XS1.1. The other end of the normally open closed contact KA2-1 of the high-voltage DC relay KA2 is connected to one end of the capacitor C1. The other end of the capacitor C1 is connected to one end of the capacitor C2. The other end of the capacitor C2 is connected to the negative pole of the high-voltage DC power supply through the electrical connector XS1.2. A wire is led out between the normally open closed contact KA2-1 and the capacitor C1 and connected to the positive power supply terminal of the controller of the high-voltage DC electric scroll compressor through the electrical connector XS3.1. A wire is led out between the capacitor C2 and the electrical connector XS1.2 (i.e., the negative pole of the high-voltage DC power supply) and connected to the negative power supply terminal of the controller of the high-voltage DC electric scroll compressor through the electrical connector XS3.2.

[0020] The U, V, and W terminals of the controller of the high-voltage DC electric scroll compressor are connected to the compressor motor, the CAN_H and CAN_L terminals of the controller of the high-voltage DC electric scroll compressor are respectively connected to the control signals output by the external air-conditioning controller, the V+ terminal of the controller of the high-voltage DC electric scroll compressor is connected to the control voltage +, and the GND terminal is grounded.

[0021] The normally open made contact KA1-1 of the high-voltage DC relay KA1 is connected in series with the resistor R1 to form a series branch, and the series branch is further connected in parallel with the normally open made contact KA2-1 of the high-voltage DC relay KA2.

[0022] One end of the resistor R2 is connected between the normally open normally closed contact KA2-1 and the capacitor C1, and the other end of the resistor R2 is connected to the lead wire between the capacitor C2 and the electrical connector XS1.2.

[0023] In this embodiment, the housing is integrally welded and made of stainless steel 316L that has been passivated. The cover of the housing is pressed against the housing by silicone rubber. The high-voltage DC fuse, high-voltage DC relay, and capacitor are all fixed to the mounting base with screws. In order to prevent dust and moisture from entering the electrical box through the gaps in the cable locking parts, an electrical connector is used instead of the cable locking parts for external electrical connection. The housing of the electrical connector is made of stainless steel, and the contacts of the electrical connector are made of gold-plated copper alloy. The connection points of the electrical connector are potted with organic silicone, and the housing of the electrical connector is connected to the vehicle body through the air-conditioning housing to realize an electrostatic discharge circuit. These measures improve the waterproof, dustproof, vibration-resistant, and corrosion-resistant capabilities of the pre-charge device.

[0024] In this embodiment, the high-voltage DC relay KA1 and the high-voltage DC relay KA2 are both Class G fuses, which provide full current protection. When the high-voltage DC electric scroll compressor is overloaded or short-circuited, the circuit is quickly cut off and the arc is extinguished to ensure the safety of the air-conditioning equipment and the entire vehicle.

[0025] In this embodiment, capacitors C1 and C2 are non-polarized film capacitors, which extend the capacitor's lifespan and its ability to adapt to high and low temperature environments and high ripple currents. Film capacitors of the same specifications are selected for series connection. The number of film capacitors depends on the rated voltage of the film capacitors and the voltage of the high-voltage DC power supply. When selecting, the rated voltage of the new capacitor formed by the series connection of film capacitors of the same specifications should be no less than 1.3 times the voltage of the high-voltage DC power supply, and the capacitance should be no less than the capacitance specified in the compressor specification.

[0026] In this embodiment, the resistor R1 is a power resistor, and the resistor R1 is provided with a heat dissipation measure. When the pre-charge signal is turned on, the resistor R1 is charged as an energy storage filter element capacitor. Before the high-voltage DC electric scroll compressor is operated, the DC bus voltage is established to prevent the high-voltage DC circuit from being short-circuited at the moment the compressor is powered on, and the impact current from damaging the main circuit power components.

[0027] In this embodiment, the freewheeling diodes D1 and D2 provide a discharge circuit for the energy stored in the coil of the corresponding high-voltage DC relay, thereby preventing the peak voltage generated when the coil loses power from being introduced into the DC signal circuit.

[0028] In this embodiment, the voltage level of the high-voltage DC electric scroll compressor is mostly above 200V, and some even reach 900V. If the high-voltage DC electric scroll compressor is overloaded or short-circuited, a large amount of energy will be released rapidly in a short period of time. Therefore, a fuse must be provided in the high-voltage DC bus circuit of the high-voltage DC electric scroll compressor to ensure that the circuit is quickly cut off and the arc is extinguished when an overcurrent occurs, thereby protecting the safety of the system and the entire vehicle.

[0029] The selection of the fuse should comprehensively consider the relevant factors such as the power KW, rated working voltage V, peak voltage V, rated current A, peak current A, peak current duration s, maximum short-circuit current KA of the high-voltage DC electric scroll compressor and high-voltage DC relay parameters. The rated current of the fuse should be selected with reference to the following formula: In=Is / K, where: Is is the rated working current of the high-voltage DC electric scroll compressor; K is the comprehensive derating factor considering the working current, temperature correction, connection device conduction and altitude correction; In is the rated current of the fuse.

[0030] The rated current value of the high-voltage DC fuse is 1.2-1.5 times the calculated rated current, and the rated voltage value is 1.2-1.5 times the peak voltage V. During physical verification, the peak current of the circuit should be checked separately and the matching of the high-voltage DC relay in the circuit should be verified.

[0031] In this embodiment, when the pre-charge signal is connected, the normally open normally closed contact KA1-1 of the high-voltage DC relay KA1 closes, charging the combined capacitor formed by the series connection of capacitors C1 and C2 of the same specifications and models. The voltage across the combined capacitor is the DC bus voltage of the high-voltage DC electric scroll compressor. When the air conditioning controller detects that the DC bus voltage fed back by the CAN communication is greater than the minimum voltage value allowed for the high-voltage DC electric scroll compressor to start, the working signal is connected, the normally open normally closed contact KA2-1 of the high-voltage DC relay KA2 closes, and the air conditioning controller controls the coil of the high-voltage DC relay KA1 to de-energize after a delay of 1 second, turning off the pre-charge. After another delay of 1 second, the air conditioning controller sends a power-on command to the compressor's built-in controller via CAN communication, starting at half the rated speed and starting with a low current.

[0032] In this embodiment, resistor R2 limits current and provides an energy dissipation circuit for the capacitor after the high-voltage DC voltage is removed. Each high-voltage DC relay coil is connected in reverse parallel to a freewheeling diode. When the precharge or operating signal is disconnected, the resistor in the high-voltage DC relay coil and the freewheeling diode form an energy dissipation circuit, preventing the voltage spike generated by the coil power loss from being introduced into the DC signal circuit.

[0033] The preferred embodiments of the present invention are described in detail above with reference to the accompanying drawings. The embodiments described in the present invention are merely descriptions of the preferred embodiments of the present invention and do not limit the concept and scope of the present invention. The various specific technical features described in the above specific embodiments can be combined in any suitable manner unless there is any contradiction. Such combinations should also be regarded as the contents disclosed in this disclosure as long as they do not violate the concept of the present invention. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0034] The present invention is not limited to the specific details of the above-mentioned embodiments. Within the scope of the technical concept of the present invention and without departing from the design concept of the present invention, various modifications and improvements made to the technical solution of the present invention by those skilled in the art should fall within the scope of protection of the present invention. The technical contents for which protection is sought in the present invention have been fully recorded in the claims.

Claims

1. A high-voltage DC electric scroll compressor pre-charging device, characterized in that: Including high-voltage DC relay (KA1), high-voltage DC relay (KA2), capacitor (C1), capacitor (C2), resistor (R1), resistor (R2), freewheeling diode (D1), freewheeling diode (D2), high-voltage DC fuse (FU1); One end of the coil of the high-voltage DC relay (KA1) is connected to a precharge signal output by an external controller, one end of the coil of the high-voltage DC relay (KA2) is connected to a working signal output by the external controller, and the other ends of the coils of the high-voltage DC relay (KA1) and the high-voltage DC relay (KA2) are connected together and then grounded; The freewheeling diode (D1) is connected in reverse parallel to the coil of the high-voltage DC relay (KA1), and the freewheeling diode (D2) is connected in reverse parallel to the coil of the high-voltage DC relay (KA2); One end of the normally open closed contact (KA2-1) of the high-voltage DC relay (KA2) is connected to the positive electrode of the high-voltage DC power supply through the high-voltage DC fuse (FU1), the other end of the normally open closed contact (KA2-1) of the high-voltage DC relay (KA2) is connected to one end of the capacitor (C1), the other end of the capacitor (C1) is connected to one end of the capacitor (C2), the other end of the capacitor (C2) is connected to the negative electrode of the high-voltage DC power supply, and a wire is led between the normally open closed contact (KA2-1) and the capacitor (C1) to connect to the positive power supply terminal of the controller provided with the high-voltage DC electric scroll compressor, and a wire is led between the capacitor (C2) and the negative electrode of the high-voltage DC power supply to connect to the negative power supply terminal of the controller provided with the high-voltage DC electric scroll compressor; The normally open / closed contact (KA1-1) of the high-voltage DC relay (KA1) is connected in series with the resistor (R1) to form a series branch, and the series branch is then connected in parallel with the normally open / closed contact (KA2-1) of the high-voltage DC relay (KA2); One end of the resistor (R2) is connected between the normally open normally closed contact (KA2-1) and the capacitor (C1), and the other end of the resistor R2 is connected to the lead wire between the capacitor (C2) and the negative electrode of the high-voltage DC power supply.

2. A high-voltage direct current electric scroll compressor pre-charging device according to claim 1, characterized in that: The high-voltage DC relay (KA1) and the high-voltage DC relay (KA2) are both Class G fuses.

3. A high-voltage direct current electric scroll compressor pre-charging device according to claim 1, characterized in that: The capacitor (C1) and the capacitor (C2) are non-polar film capacitors.

4. A high-voltage direct current electric scroll compressor pre-charging device according to claim 1, characterized in that: The resistor (R1) is a power resistor.

5. A high-voltage DC electric scroll compressor pre-charging device according to any one of claims 1 to 4, characterized in that: The high-voltage DC relay (KA1), the high-voltage DC relay (KA2), the capacitor (C1), the capacitor (C2), the resistor (R1), the resistor (R2), the freewheeling diode (D1), the freewheeling diode (D2), and the high-voltage DC fuse (FU1) are arranged in the same housing. The housing is provided with a plurality of electrical connectors, which are respectively used to connect an external controller, a high-voltage DC power supply, and a controller provided with the high-voltage DC electric scroll compressor.