Inverter for cooling and heating system

Abstract

The present invention relates to an inverter of a cooling and heating system. The inverter of a cooling and heating system, according to one embodiment of the present invention, controls each of a motor of an electric compressor for cooling and a positive temperature coefficient (PTC) heater for heating, and comprises: a power source unit for supplying a power source; a DC capacitor for storing a direct current power source that is input from the power source unit; a power conversion unit having a plurality of switching elements, and converting, on the basis of the switching operations of respective switching elements, the direct current power source stored in the DC capacitor into an alternating current power source so as to output same to a motor; a PTC switching unit connected to the PTC heater in series so as to switch whether the direct current power source of the DC capacitor is applied to the PTC heater; a converter for converting each of a signal of one end of the DC capacitor, a signal of the power conversion unit, and a signal of one end of the PTC heater into a digital signal; and a digital isolator which converts the digital signal into an output signal to transmit same to a control unit, and which insulates the converter and the control unit.

Description

Inverters for heating and cooling systems

[0001] The present invention relates to an inverter for a heating and cooling system, and more particularly, to a signal detection device in the inverter.

[0002] Vehicles, home appliances, or air conditioners (hereinafter referred to as "target devices") are equipped with a heating and cooling system capable of operating both cooling and heating. These heating and cooling systems include an electric compressor, a device that compresses refrigerant for the cooling system, and a PTC (Positive Temperature Coefficient) heater for the heating system. Furthermore, the heating and cooling system also includes a control device for controlling the motor for the electric compressor and the PTC heater, respectively.

[0003] In particular, electric compressors are devices that compress refrigerant by rotating a motor powered by electricity. Electric compressors are essential for eco-friendly vehicles. For example, eco-friendly vehicles may be HEVs (Hybrid Electric Vehicles), PHEVs (Plug-in Hybrid Electric Vehicles), or EVs (Electric Vehicles).

[0004] These eco-friendly vehicles include an inverter that supplies voltage and current to the motor and PTC heater of the electric compressor, respectively, based on power from a high-capacity, high-voltage battery. This inverter detects the voltage and current and controls the operation of the motor and PTC heater based on these signals. Conventional technologies typically require multiple isolated amplifier components (OP-AMPs) to isolate and detect analog signals from the power supply. However, these isolated amplifier components increase the size of the inverter and the cost of the components. Of course, this problem can also apply to inverters in heating and cooling systems of other devices that incorporate both an electric compressor for cooling and a PTC heater for heating.

[0005] However, the above-described content merely provides background information on the present invention and does not correspond to previously disclosed technology.

[0006] In order to solve the problems of the above-described prior art, the present invention aims to provide a signal detection device for an inverter of a heating and cooling system capable of detecting voltage and current supplied to a motor and a PTC heater of an electric compressor, respectively, with a small volume and cost without an insulation amplifier element.

[0007] In addition, another object of the present invention is to provide a signal detection device for an inverter of a heating and cooling system capable of detecting voltage and current supplied to a motor of an electric compressor and a PTC heater, respectively, by separating the ground group of a high-voltage battery and the ground group of a control unit.

[0008] According to one embodiment of the present invention for solving the above technical problem, an inverter of a heating and cooling system is provided, which is an inverter of a heating and cooling system that performs control of a motor of an electric compressor for cooling and a PTC (Positive Temperature Coefficient) heater for heating, respectively, and includes: a power supply unit that supplies power; a DC capacitor that stores DC power input from the power supply unit; a power conversion unit that has a plurality of switching elements and converts the DC power stored in the DC capacitor into AC power based on a switching operation of each switching element and outputs the converted AC power to a motor; a PTC switching unit that is connected in series with the PTC heater and switches whether the DC power of the DC capacitor is applied to the PTC heater; and a converter that converts a signal of one end of the DC capacitor, a signal of the power conversion unit, and a signal of one end of the PTC heater into digital signals, respectively; and a digital isolator that converts the digital signal into an output signal and transmits the signal to a control unit, and insulates the converter and the control unit.

[0009] An inverter of a heating and cooling system according to one embodiment of the present invention may further include a control unit that controls a switching operation of the power conversion unit and a switching operation of the PTC switching unit based on the output signal.

[0010] The grounds of the above converter and the above control unit can be configured to be separated from each other.

[0011] The input terminal of the digital isolator may be configured to share the ground loop of the converter, and the output terminal of the digital isolator may be configured to share the ground loop of the control unit.

[0012] The digital isolator may include at least one capacitor that insulates the digital signal and the output signal.

[0013] The above output signal may be a signal in which the digital signal is transmitted in a serial synchronous manner.

[0014] The above output signal may be a signal transmitted in one of the following ways: SPI (SERIAL PERIPHERAL INTERFACE) or I2C (INTER-INTERGRATED CIRCUIT).

[0015] The present invention, configured as described above, has the advantage of being able to detect the voltage and current supplied to the motor and PTC heater of the electric compressor, respectively, with a small volume and cost, without being affected by the noise of the high-voltage battery.

[0016] In addition, the present invention has an advantage in that the ground group of the high-voltage battery and the ground group of the control unit can be separated to detect the voltage and current supplied to the motor and PTC heater of the electric compressor, respectively.

[0017] However, the effects that can be obtained from the present invention are not limited to the effects mentioned above, and other effects that are not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present invention belongs from the description below.

[0018] Figure 1 shows a schematic block diagram of a heating and cooling system according to one embodiment of the present invention.

[0019] Figure 2 shows a block diagram of an inverter of a heating and cooling system according to one embodiment of the present invention.

[0020] Figure 3 shows a circuit diagram for an inverter of a heating and cooling system according to one embodiment of the present invention.

[0021] FIG. 4 is a drawing showing the ground separation of an inverter of a heating and cooling system according to one embodiment of the present invention.

[0022] FIG. 5 and FIG. 6 are drawings showing the configuration of a digital isolator according to one embodiment of the present invention.

[0023] The present invention relates to an inverter of a heating and cooling system that performs control of a motor of an electric compressor for cooling and a PTC (Positive Temperature Coefficient) heater for heating, respectively, and provides an inverter of a heating and cooling system, including a power supply unit that supplies power, a DC capacitor that stores DC power input from the power supply unit, a power conversion unit that has a plurality of switching elements and converts the DC power stored in the DC capacitor into AC power based on a switching operation of each switching element and outputs it to a motor, a PTC switching unit that is connected in series with the PTC heater and switches whether the DC power of the DC capacitor is applied to the PTC heater, a converter that converts a signal of a terminal of the DC capacitor, a signal of the power conversion unit, and a signal of a terminal of the PTC heater into digital signals, respectively, and a digital isolator that converts the digital signal into an output signal and transmits it to a control unit, and insulates the converter and the control unit.

[0024] The description of the present invention is merely an example for structural and functional explanation, and therefore, the scope of the present invention should not be construed as being limited by the embodiments described in the text. That is, since the embodiments can be modified in various ways and can take various forms, the scope of the present invention should be understood to include equivalents that can realize the technical idea. In addition, the purposes or effects presented in the present invention do not mean that a specific embodiment must include all of them or only such effects, and therefore, the scope of the present invention should not be construed as being limited thereby.

[0025] Meanwhile, the meaning of the terms described in this application should be understood as follows.

[0026] Terms such as "first" and "second" are intended to distinguish one component from another, and the scope of the rights should not be limited by these terms. For example, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component.

[0027] When a component is said to be "connected" to another component, it should be understood that while it may be directly connected to that other component, there may also be other components intervening. Conversely, when a component is said to be "directly connected" to another component, it should be understood that there are no other intervening components. Similarly, other expressions describing relationships between components, such as "between" and "directly between," or "adjacent to" and "directly adjacent to," should be interpreted similarly.

[0028] Singular expressions should be understood to include plural expressions unless the context clearly indicates otherwise, and terms such as "comprises" or "have" should be understood to specify the presence of a feature, number, step, operation, component, part or combination thereof, but not to exclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0029] For each step, the identifiers (e.g., a, b, c, etc.) are used for convenience of explanation and do not describe the order of the steps. The steps may occur in a different order than stated unless the context clearly dictates a specific order. That is, the steps may occur in the same order as stated, may be performed substantially simultaneously, or may be performed in the opposite order.

[0030] The present invention can be implemented as computer-readable code on a computer-readable recording medium, and the computer-readable recording medium includes all types of recording devices that store data that can be read by a computer system. Examples of the computer-readable recording medium include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage device, etc., and also includes those implemented in the form of a carrier wave (e.g., transmission via the Internet). Furthermore, the computer-readable recording medium can be distributed across network-connected computer systems, so that the computer-readable code can be stored and executed in a distributed manner.

[0031] Unless otherwise defined, all terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries should be interpreted to be consistent with their meaning within the context of the relevant technology, and should not be interpreted as having an idealized or overly formal meaning unless explicitly defined herein.

[0032] Hereinafter, a preferred embodiment according to the present invention will be described in detail with reference to the attached drawings.

[0033] Figure 1 shows a schematic block diagram of a heating and cooling system (1) according to one embodiment of the present invention.

[0034] A heating and cooling system (1) according to one embodiment of the present invention (hereinafter referred to as "the system") is a system capable of operating cooling and heating, respectively, and includes a cooling system for cooling and a heating system for heating. At this time, the cooling system may include an electric compressor (200) that is a device for compressing a refrigerant, and the heating system may include a PTC (Positive Temperature Coefficient) heater (300) that generates heat according to the PTC (Positive Temperature Coefficient) principle. For example, target devices to which the system (1) is applied may be, but are not limited to, vehicles, home appliances, air conditioners, etc.

[0035] To this end, referring to FIG. 1, the system (1) includes an inverter (100), an electric compressor (200), and a PTC heater (300). At this time, the electric compressor (200) includes a motor (210) that provides power for compressing a refrigerant when power is supplied under the control of the inverter (100). In addition, the PTC heater (300) is a heating element made of a barium titanate-based material having a positive temperature coefficient in which the size of the resistance increases as the temperature rises. At this time, the PTC heater (300) performs a heating operation when power is supplied under the control of the inverter (100), and accordingly, when a specific temperature is reached, the resistance of the PTC heater (300) increases significantly, so that the current flowing through the PTC heater (300) decreases, thereby preventing overheating.

[0036] That is, the motor (210) and the PTC heater (300) are components that operate by power supplied under the control of the inverter (100), and correspond to core components for the cooling operation of the electric compressor (200) as a cooling system and the heating operation of the PTC heater (300) as a heating system in the present system (1). At this time, the inverter (100) can control the operations of the motor (210) and the PTC heater (300) respectively through power control. That is, in the present system (1), the operations of the motor (210) and the PTC heater (300) are respectively controlled through one inverter (100), and accordingly, the cooling and heating operations of the electric compressor (200) as a cooling system and the PTC heater (300) as a heating system can be controlled.

[0037] If the target device is a vehicle, it may be desirable for the vehicle to be environmentally friendly. Examples of environmentally friendly vehicles include, but are not limited to, a Hybrid Electric Vehicle (HEV), a Plug-in Hybrid Electric Vehicle (PHEV), or an Electric Vehicle (EV).

[0038] FIG. 2 shows a block diagram of an inverter (100) of a heating and cooling system (1) according to one embodiment of the present invention, and FIG. 3 shows a circuit diagram of an inverter (100) of a heating and cooling system (1) according to one embodiment of the present invention.

[0039] The inverter (100) can not only perform a function of controlling the operation of the motor (210) by controlling the power supplied to the motor (210) (i.e., the “first function”), but also perform a function of controlling the operation of the PTC heater (300) by controlling the power supplied to the PTC heater (300) (i.e., the “second function”). That is, the inverter (100) can control the operation of the motor (210) and the PTC heater (300) by controlling the power supply to the motor (210) and the PTC heater (300) according to the first and second functions. To this end, referring to FIGS. 2 and 3, the inverter (100) may include a power supply unit (10), a DC capacitor (20), a power conversion unit (30), a PTC switching unit (40), a converter (50), a digital isolator (60), and a control unit (70). Of course, the inverter (100) may further include a noise filter unit (11) and an inductor (12). At this time, a configuration including a converter (50), a digital isolator (60), and a control unit (70) may be referred to as a “signal detection device.”

[0040] The power supply unit (10) can receive direct current power from the battery of the target device. At this time, the direct current power of the battery may be a high voltage (e.g., 48 V). That is, the power supply unit (10) can receive a high voltage external direct current power and supply direct current power for driving the motor (210) and the PTC heater (300).

[0041] The noise filter unit (11) is a circuit configuration for removing noise from the DC power supplied from the battery and transmitting it to the DC capacitor (20). Accordingly, the noise filter unit (11) may be provided between the power supply unit (10) and the DC capacitor (20). However, the symbol for the noise filter unit (11) is only shown in Fig. 3.

[0042] The inductor (12) can be connected to one end of a DC capacitor (20). At this time, the inductor (12) can operate as a filter to block the AC component and pass only the DC component together with the DC capacitor (20).

[0043] The DC capacitor (20) receives DC power from the power supply unit (10) and charges or discharges the DC power. Regarding this DC capacitor (20), although it is illustrated as a single capacitor in the drawing, it is not limited thereto, and the DC capacitor (20) may be in the form of multiple capacitors connected in series or parallel.

[0044] The power conversion unit (30) is provided with a plurality of switching elements, and can convert the direct current power stored in the DC capacitor (20) into alternating current power based on the switching operation of each switching element and output it to the motor (210). Each switching element constituting the power conversion unit (30) can switch the direct current voltage / current by the input DC capacitor (20) and output it as a three-phase alternating current voltage / current capable of driving the motor (210). For example, the power conversion unit (30) can convert the input direct current power into three-phase alternating current power and output it to the motor (210) by turning each switching element on or off. At this time, whether each switching element of the power conversion unit (30) is on / off can be controlled by the control unit (70). That is, the control unit (70) can generate a control signal for controlling the switching operation of each switching element based on a plurality of output signals (signals for voltage and current) for the power conversion unit (30). At this time, the control signal may correspond to a PWM signal. For example, the power conversion unit (30) can convert the input DC voltage into a three-phase AC voltage and output it to the motor (210) by turning each switching element on / off. At this time, the current flowing in the power conversion unit (30) may correspond to a high current having a relatively high value, and the inverter (100) can electrically connect the power conversion unit (30) and the converter (50) to measure the current transmitted to the motor (210), which will be described in detail below.

[0045] The PTC switching unit (40) has a switching element connected in series with the PTC heater (300), and switches whether the DC power stored in the DC capacitor (20) is applied to the PTC heater (300) based on the switching operation of the corresponding switching element. For example, the PTC switching unit (40) can operate so that the input DC power is supplied to the PTC heater (300) or the corresponding supply is cut off by turning the corresponding switching element on or off. At this time, whether the corresponding switching element of the PTC switching unit (40) is on / off can be controlled by the control unit (70). That is, the control unit (70) can generate a control signal for the corresponding switching element based on a signal flowing in one end of the PTC heater (300) (i.e., a signal for current). At this time, the control signal may correspond to a PWM signal.

[0046] The converter (50) is electrically connected to the DC capacitor (20), the power conversion unit (30) and the PTC heater (300) to convert the signal of one end of the DC capacitor (20), the analog signal of the power conversion unit (30) and the analog signal of the PTC heater (300) into a digital signal and can communicate to transmit information of the digital signal to the digital isolator (60). More specifically, the converter (50) can communicate with the analog signal (V) for the voltage and current detected at one end of the DC capacitor (20). dc , I dc ) and an analog signal (I) for the current detected in multiple switching elements of the power conversion unit (30). a , I b , I c ) and an analog signal (PTC_I) for the current detected at one end of the PTC heater (300). a) into a digital signal and can communicate the information of the digital signal with the digital isolator (60). At this time, the converter (50) can receive an analog signal of the voltage or current through a sensor or shunt resistor that measures the magnitude of the voltage or current of a node electrically connected to the DC capacitor (20), the power conversion unit (30), and the PTC heater (300).

[0047] The control unit (70) can control the operation of the inverter (100). In particular, the control unit (70) can control the performance of the first and second functions. That is, in the inverter (100), the direct current power supplied from the power supply unit (10) is stored on the DC capacitor (20). At this time, with respect to the first function, the power conversion unit (30) is controlled by the control unit (70), so that the direct current power is converted into alternating current power and supplied to the motor (210), thereby driving the motor (210). In addition, with respect to the second function, the PTC switching unit (40) is controlled by the control unit (70), so that the power stored in the DC capacitor (20) is applied to the PTC heater (300), thereby driving the PTC heater (300).

[0048] The control unit (70) may include a processor (not shown) and a memory (not shown). The processor may be implemented as an MCU or the like, and may control the overall operation of the power conversion unit (30) and the PTC switching unit (40) using information stored in the memory. At this time, the memory may store programs and various data for processing or controlling the processor. For example, the memory may include not only volatile memory such as S-RAM and D-RAM, but also non-volatile memory such as flash memory, ROM (Read Only Memory), and EPROM (Erasable Programmable Read Only Memory).

[0049] In particular, the power supplied from the power supply unit (10) corresponds to high voltage. Accordingly, in the prior art, in order to detect the voltage and current of the high-voltage node, an isolated amplifier element (isolated OP-AMP) was separately added for each node, and a problem occurred in that the volume of the inverter increased due to the isolated amplifier element and the price of the components increased. Accordingly, in the present invention, the problem can be solved by replacing the isolated amplifier element (isolated OP-AMP) with a converter (50) and a digital isolator (60).

[0050] FIG. 4 is a drawing showing the ground separation of an inverter (100) of a heating and cooling system according to one embodiment of the present invention, and FIG. 5 is a drawing showing the configuration of a digital isolator (60) according to one embodiment of the present invention.

[0051] The digital signal with the ground of the converter (50) and the control unit (70) separated can transmit / receive the communication signal between the converter (50) and the control unit (70) through the digital isolator (60). For example, the digital isolator (60) can transmit the SPI (SERIAL PERIPHERAL INTERFACE) or I2C (INTER-INTERGRATED CIRCUIT) communication signal including the digital information of the voltage and current of one end of the DC capacitor (20) received through the converter (50) and the digital information of the current of one end of the power conversion unit (30) and the PTC heater (300) as an output signal to the control unit (70). Here, the digital isolator (60) can convert the SPI (SERIAL PERIPHERAL INTERFACE) or I2C (INTER-INTERGRATED CIRCUIT) communication signal received through the converter (50) into a digital signal of the same form for the digital information of the corresponding voltage and current. Additionally, the digital isolator (60) may be connected to a plurality of ground loops, and may include a first ground loop that receives a digital signal and a second ground loop that is connected to an output signal that is transmitted to the control unit (70).

[0052] The converter (50) can assign one or more channels to an analog signal for the current of a DC capacitor (20) and another one or more channels to an analog signal for the voltage of a DC capacitor (20). In addition, channels can be assigned to both ends of a shunt resistor located at one end of a power conversion unit (30) and a PTC heater (300).

[0053] In one embodiment, referring to FIGS. 4 and 5, the digital isolator (60) may be configured such that the converter (50) and the input terminal (61) share a ground loop, and the control unit (70) and the output terminal (62) share a ground loop. As described above, the digital isolator (60) may be connected to a plurality of ground loops. The digital isolator (60) may include an input terminal (61) and an output terminal (62). The input terminal (61) of the digital isolator (60) may have the same phase as the ground to which the converter (50) is connected, i.e., may be electrically connected to the same ground loop as the converter (50). Here, the input terminal (61) and the output terminal (62) of the digital isolator (60) may be separated by a capacitor (63). The output terminal (62) of the digital isolator (60) has the same phase as the ground to which the control unit (70) is connected, i.e., it can be electrically connected to the same ground loop as the control unit (70). Therefore, the digital isolator (60) can be configured to separate the ground of the digital signal of the input terminal (61) and the digital signal of the output terminal (62) so that the digital signal of the input terminal (61) does not affect the digital signal of the output terminal (62). Accordingly, the inverter (100) can be configured to separate the ground of the signal of the power supply unit (10) including the analog signal and the signal input from the control unit (70) so that the control unit (70) can detect and control the signal more stably. In addition, the inverter (100) can stably detect and control the signal through the converter (50) and the digital isolator (60) in an electronic control system that handles high voltage and high power, such as an electric vehicle or a hybrid vehicle.

[0054] In one embodiment, the grounds of the converter (50) and the control unit (70) may be configured to be separated from each other. As described above, the converter (50) and the control unit (70) may each be electrically connected to a digital isolator (60). The converter (50) and the control unit (70) may each be connected to a ground, and the digital isolator (60) may be connected to two grounds, which may be a ground loop to which the converter (50) is connected or a ground loop to which the control unit (70) is connected. That is, the converter (50) and the control unit (70) may be configured to have grounds electrically connected to each other by the digital isolator (60) to be separated from each other.

[0055] In one embodiment, the converter (50) can convert an analog signal into a digital signal and transmit the digital signal to the digital isolator (60) for communication. At this time, the digital isolator (60) can transmit the communication signal of the converter (50) in a serial synchronous manner. For example, the digital isolator (60) can sequentially transmit the communication signal of the converter (50) that detects and converts the signal for the voltage and current of one end of the DC capacitor (20) to the control unit (70). As another example, the digital isolator (60) can sequentially transmit the communication signal of the converter (50) that detects and converts the current signal of one end of the power conversion unit (30) and the PTC heater (300) to the control unit (70). That is, the voltage and current analog signals of one end of the DC capacitor (20) and the current analog signals of one end of the power conversion unit (30) and the PTC heater (300) can each be converted into digital signals through the converter (50) and output through communication. The digital isolator (60) can communicate with the control unit (70) regarding the generated communication signals. In addition, the digital isolator (60) can synchronize the digital signal generated by the converter (50) with the signal received by the control unit (70). Accordingly, the digital isolator (60) can serially transmit the signal generated by the converter (50) and the signal whose clock is synchronized to the control unit (70).

[0056] In one embodiment, the converter (50) can convert an analog signal into a digital signal and transmit it in either a SPI (SERIAL PERIPHERAL INTERFACE) or I2C (INTER-INTERGRATED CIRCUIT) manner. In addition, the digital isolator (60) can isolate a digital signal and transmit the digital signal to the control unit (70).

[0057] Although the present invention has been described above with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various modifications and changes may be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below.

Claims

1. In an inverter of a heating and cooling system that performs control of the motor of an electric compressor for cooling and the PTC (Positive Temperature Coefficient) heater for heating, respectively, Power supply unit that supplies power; A DC capacitor that stores direct current power input from the above power supply; A power conversion unit having a plurality of switching elements and converting direct current power stored in the DC capacitor into alternating current power based on the switching operation of each switching element and outputting it to a motor; A PTC switching unit that is connected in series with the PTC heater and switches whether the DC power of the DC capacitor is applied to the PTC heater; and A converter that converts the signal of the DC capacitor group, the signal of the power conversion unit, and the signal of the PTC heater group into digital signals, respectively; and An inverter of a heating and cooling system, comprising a digital isolator that converts the digital signal into an output signal and transmits it to a control unit, and insulates the converter and the control unit.

2. In paragraph 1, An inverter for a heating and cooling system further comprising a control unit that controls the switching operation of the power conversion unit and the switching operation of the PTC switching unit based on the output signal.

3. In paragraph 2, An inverter of a heating and cooling system in which the grounds of the converter and the control unit are configured to be separated from each other.

4. In paragraph 3, An inverter for a heating and cooling system, characterized in that the input terminal of the digital isolator shares the ground loop of the converter, and the output terminal of the digital isolator shares the ground loop of the control unit.

5. In paragraph 1, The above converter, An inverter of a heating and cooling system that converts the voltage or current of the DC capacitor group, the current of the plurality of switching elements, and the current of the PTC heater group into the digital signal.

6. In paragraph 1, The above digital isolator, An inverter of a heating and cooling system comprising at least one capacitor that insulates the digital signal and the output signal.

7. In paragraph 1, The above output signal is an inverter of a heating and cooling system in which the above digital signal is transmitted in a serial synchronous manner.

8. In paragraph 1, The above output signal is an inverter of a heating and cooling system, wherein the digital signal is transmitted in one of the SPI (SERIAL PERIPHERAL INTERFACE) or I2C (INTER-INTERGRATED CIRCUIT) methods.

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