Novel electric compressor control circuit

Abstract

The invention discloses a novel electric compressor control circuit, which comprises an IGBT (Insulated Gate Bipolar Transistor), a driving circuit, a master control single chip microcomputer and an external safety circuit, the output ends of the IGBT and the driving circuit are connected with an OPAMP (Operational Amplification Multi-Point) operational amplifier module, and an amplified signal is sent to an ADC (Analog-to-Digital Converter) module of the master control single chip microcomputer for current closed-loop control of a permanent magnet synchronous motor on one hand; on the other hand, the current is sent to the COMP comparison module for detecting whether overcurrent occurs; when overcurrent occurs, an error signal generated by the COMP comparison module is sent to the Timer timer module, so that the PWM stops sending waves, and the IGBT is protected; and the external safety circuit is used for monitoring the execution of the ADC interrupt service function of the master control single chip microcomputer. According to the invention, the high and low levels of the IO port are overturned in the ADC interruption service function, and the half-wave rectification circuit is utilized to output the voltage to judge whether the single-chip microcomputer normally operates the motor control loop, so that the reliability of abnormal conditions is improved.

Description

Technical Field

[0001] This invention relates to the field of control, specifically a novel control circuit for an electric compressor. Background Technology

[0002] Electric compressors are essential components of new energy vehicles. To ensure passenger comfort in hot and cold environments, air conditioning systems have been developed. An air conditioning system consists of a compressor, condenser, evaporator, expansion valve, and receiver-drier. The compressor compresses the low-temperature gaseous refrigerant into a high-temperature, high-pressure gaseous refrigerant, which is then liquefied in the condenser to release heat and carry it into the outside air.

[0003] Traditional gasoline-powered vehicles use an engine connected to an electromagnetic clutch to rotate the compressor body and compress gas. New energy vehicles, however, do not have an engine; instead, they use a permanent magnet synchronous motor to drive a rotating disc, which in turn compresses the refrigerant. The permanent magnet synchronous motor receives DC power from the high-voltage battery pack of the new energy vehicle and converts it into a three-phase drive voltage via a controller, enabling the motor to rotate. Figure 1 A typical control circuit for an electric compressor controller consists of an IGBT, a drive circuit, a sampling resistor, an operational amplifier circuit, and a main control MCU. To protect the IGBT's normal operation, it also includes overvoltage protection, undervoltage protection, overcurrent protection, and overtemperature protection. Existing electric compressor control circuits use peripheral components such as operational amplifiers, comparators, and voltage reference chips to achieve these protection functions, resulting in high costs. Furthermore, because electric compressors operate in vehicle-mounted environments with high requirements for interference and reliability, existing electric compressor controllers on the market occasionally exhibit excessively high failure rates. Summary of the Invention

[0004] This invention addresses the problems existing in the background art by proposing a novel electric compressor control circuit.

[0005] Technical solution:

[0006] This invention discloses a novel electric compressor control circuit, including an IGBT, a drive circuit, a main control microcontroller, and an external safety circuit. The output of the IGBT and drive circuit is connected to an OPAMP operational amplifier module. The amplified signal is sent to the ADC analog-to-digital converter module of the main control microcontroller for current closed-loop control of the permanent magnet synchronous motor; on the other hand, it is sent to the COMP comparator module to detect whether an overcurrent has occurred. When an overcurrent occurs, the error signal generated by the COMP comparator module is sent to the Timer module, causing the PWM to stop emitting waves and protecting the IGBT. The external safety circuit is used to monitor the execution of the ADC interrupt service function of the main control microcontroller.

[0007] Preferably, both the OPAMP operational amplifier module and the COMP comparator module are built into the main control microcontroller.

[0008] Preferably, the reference voltage of the OPAMP operational amplifier module is generated by the microcontroller's DAC digital-to-analog converter module.

[0009] Preferably, the external safety circuit includes a first transistor Q1, a second transistor Q2, a first resistor R1, a second resistor R2, a third resistor R3, a first diode D1, a second diode D2, a first capacitor C1, and a second capacitor C2. The I / O interface of the main control microcontroller is connected to the base of the first transistor Q1, the emitter of the first transistor Q1 is grounded, and the collector of the first transistor Q1 is connected to the power supply voltage of the main control microcontroller through the first resistor R1. The collector of the first transistor Q1 is also sequentially connected to the first capacitor C1. 1. The anode and cathode of the first diode D1 are connected to the base of the second transistor Q2. The collector of the second transistor Q2 is grounded. The emitter of the second transistor Q2 is connected to the interrupt port NMI of the main control microcontroller on one hand, and to the power supply voltage of the main control microcontroller on the other hand through the third resistor R3. The base of the second transistor Q2 is grounded through the parallel second capacitor C2 and the second resistor R2. The anode of the first diode D1 is also connected to the cathode of the second diode D2, and the anode of the second diode D2 is grounded.

[0010] Preferably, the first transistor Q1 is an NPN transistor and the second transistor Q2 is a PNP transistor.

[0011] Preferably, the first resistor R1 is 1kΩ, the second resistor R2 is 100kΩ, and the third resistor R3 is 10kΩ.

[0012] Preferably, the first capacitor C1 is 1μF and the second capacitor C2 is 0.1μF.

[0013] Preferably, the first diode D1 and the second diode D2 are BAT54 Schottky diodes.

[0014] Preferably, the operation of the external safety circuit is as follows:

[0015] S1. When the high and low levels of the main control microcontroller's IO port are toggled in the interrupt of the ADC analog-to-digital conversion module, a PWM waveform with a 50% duty cycle is formed, denoted as signal IO_Sim_PWM. Signal IO_Sim_PWM causes the first transistor Q1 to be intermittently turned on and off, and the collector voltage of the first transistor Q1 is a square wave signal with a low level of 0V and a high level of 3.3V.

[0016] S2. The square wave voltage signal of the collector of the first transistor Q1 is rectified by the half-wave rectifier circuit composed of the first capacitor C1, the first diode D1, and the second diode D2, and forms a voltage of 3.3V as the base voltage of the second diode Q2.

[0017] S3, Monitoring Status:

[0018] 1) When the ADC interrupt service function of the main control microcontroller is executed normally, the base voltage of the second diode Q2 is 3.3V. The base voltage of Q2 is the same as the emitter voltage. Q2 is not conducting and is in the cutoff state. Fault_Out is high level 3.3V.

[0019] 2) When the ADC interrupt service function of the main control microcontroller is executed abnormally or enters an error state, the base voltage of the second diode Q2 is 0V. Since the base voltage of Q2 is lower than the emitter voltage, Q2 is turned on, and Fault_Out is low level 0V.

[0020] The IO_Sim_PWM signal of the main control microcontroller is toggled to monitor the normal execution of the ADC interrupt service function. When a microcontroller error occurs, Fault_Out can stop the permanent magnet synchronous motor from generating waves or reset and restart the microcontroller, thereby protecting the IGBT and the main control microcontroller.

[0021] Beneficial effects:

[0022] Compared to traditional electric compressor control circuits, this circuit reduces the use of external operational amplifier chips, comparator chips, and voltage reference chips, thus saving costs. At the same time, the use of interrupt-driven I / O port toggling effectively protects the correct operation of the microcontroller and IGBTs. Attached Figure Description

[0023] Figure 1 The background diagram shows the control circuit diagram of a traditional electric compressor.

[0024] Figure 2 This is a control circuit diagram of the novel electric compressor of the present invention.

[0025] Figure 3 for Figure 2 Circuit diagram of the external safety circuit.

[0026] Figure 4 This is a simulation waveform for an external safety circuit. Detailed Implementation

[0027] The present invention will be further described below with reference to embodiments, but the scope of protection of the present invention is not limited thereto:

[0028] Combination Figure 2A novel electric compressor control circuit includes an IGBT, a drive circuit, a main control microcontroller, and an external safety circuit. The output of the IGBT and drive circuit is connected to an OPAMP operational amplifier module. The amplified signal is sent to the ADC analog-to-digital converter module of the main control microcontroller for current closed-loop control of the permanent magnet synchronous motor; on the other hand, it is sent to a COMP comparator module to detect overcurrent. When overcurrent occurs, the error signal generated by the COMP comparator module is sent to a Timer module, causing the PWM to stop waving and protecting the IGBT. The external safety circuit is used to monitor the execution of the ADC interrupt service function of the main control microcontroller.

[0029] In this embodiment, both the OPAMP operational amplifier module and the COMP comparator module are built into the main control microcontroller.

[0030] In this embodiment, the reference voltage of the OPAMP operational amplifier module is generated by the DAC digital-to-analog converter module of the microcontroller.

[0031] Combination Figure 3 The external safety circuit includes a first transistor Q1, a second transistor Q2, a first resistor R1, a second resistor R2, a third resistor R3, a first diode D1, a second diode D2, a first capacitor C1, and a second capacitor C2. The I / O interface of the main control microcontroller is connected to the base of the first transistor Q1, the emitter of the first transistor Q1 is grounded, and the collector of the first transistor Q1 is connected to the power supply voltage of the main control microcontroller through the first resistor R1. The collector of the first transistor Q1 is also connected sequentially to the anode of the first capacitor C1 and the first diode D1. The cathode of the first diode D1 is connected to the base of the second transistor Q2, the collector of the second transistor Q2 is grounded, and the emitter of the second transistor Q2 is connected to the interrupt port NMI of the main control microcontroller on one hand, and to the power supply voltage of the main control microcontroller on the other hand through the third resistor R3. The base of the second transistor Q2 is grounded through the second capacitor C2 and the second resistor R2 connected in parallel. The anode of the first diode D1 is also connected to the cathode of the second diode D2, and the anode of the second diode D2 is grounded.

[0032] In this embodiment, the first transistor Q1 is an NPN transistor, and the second transistor Q2 is a PNP transistor. The first resistor R1 is 1kΩ, the second resistor R2 is 100kΩ, and the third resistor R3 is 10kΩ. The first capacitor C1 is 1μF, and the second capacitor C2 is 0.1μF. The first diode D1 and the second diode D2 are BAT54 battery voltage sensors.

[0033] The operation of the external safety circuit of this invention is as follows:

[0034] S1. When the high and low levels of the main control microcontroller's IO port are toggled in the interrupt of the ADC analog-to-digital conversion module, a PWM waveform with a 50% duty cycle is formed, denoted as signal IO_Sim_PWM. Signal IO_Sim_PWM causes the first transistor Q1 to be intermittently turned on and off, and the collector voltage of the first transistor Q1 is a square wave signal with a low level of 0V and a high level of 3.3V.

[0035] S2. The square wave voltage signal of the collector of the first transistor Q1 is rectified by the half-wave rectifier circuit composed of the first capacitor C1, the first diode D1, and the second diode D2, and forms a voltage of 3.3V as the base voltage of the second diode Q2.

[0036] S3, Monitoring Status:

[0037] 1) When the ADC interrupt service function of the main control microcontroller is executed normally, the base voltage of the second diode Q2 is 3.3V. The base voltage of Q2 is the same as the emitter voltage. Q2 is not conducting and is in the cutoff state. Fault_Out is high level 3.3V.

[0038] 2) When the ADC interrupt service function of the main control microcontroller is executed abnormally or enters an error state, the base voltage of the second diode Q2 is 0V. Since the base voltage of Q2 is lower than the emitter voltage, Q2 is turned on, and Fault_Out is low level 0V.

[0039] The IO_Sim_PWM signal of the main control microcontroller is toggled to monitor the normal execution of the ADC interrupt service function. When a microcontroller error occurs, Fault_Out can stop the permanent magnet synchronous motor from generating waves or reset and restart the microcontroller, thereby protecting the IGBT and the main control microcontroller.

[0040] The present invention proposes a novel electric compressor control circuit, which consists of an IGBT, a drive circuit, a main control microcontroller, and a protection circuit.

[0041] Compared with traditional control circuits, the novel electric compressor control circuit eliminates the need for buffer chips, operational amplifier chips, comparator chips, and latch logic devices, while adding an external safety circuit to monitor the execution of the microcontroller's ADC interrupt service function.

[0042] The millivolt signals generated by the three-phase and bus currents flowing through the milliohm resistors are directly fed into the OPAMP operational amplifier module inside the microcontroller. The reference voltage of the operational amplifier module is generated by the microcontroller's DAC digital-to-analog converter module. After amplification, the signal is sent to the microcontroller's ADC analog-to-digital converter module for current closed-loop control of the permanent magnet synchronous motor. At the same time, it is sent to the microcontroller's COMP comparator module to detect whether an overcurrent has occurred. When an overcurrent occurs, the error signal generated by the COMP module is sent to the Timer module, causing the PWM to stop emitting waves and protecting the IGBT.

[0043] Figure 4 for Figure 3 The simulation waveforms are shown. IO_Sim_PWM is generated after the main control microcontroller enters the ADC interrupt; V1 and V2 are the process voltage waveforms during half-wave rectification; V3 is the voltage waveform generated by half-wave rectification; and Fault_Out is the judgment voltage used to monitor whether the ADC interrupt is executed normally.

[0044] The novel electric compressor control circuit proposed in this invention has the following characteristics:

[0045] First, this circuit uses the microcontroller's built-in operational amplifier module and comparator module, eliminating the need for external operational amplifier chips and external comparators, thus saving costs;

[0046] Secondly, by using the microcontroller's DAC module to output the reference voltage, the use of an external voltage reference chip is saved.

[0047] Third, the high and low levels of the I / O port are toggled in the ADC interrupt service function. The output voltage is used to determine whether the microcontroller is operating normally in the motor control loop, which improves the reliability of abnormal situations.

[0048] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A novel electric compressor control circuit, comprising an IGBT, a drive circuit, and a main control microcontroller, characterized in that... It also includes an external safety circuit. The output of the IGBT and drive circuit is connected to the OPAMP operational amplifier module. After amplification, the signal is sent to the ADC analog-to-digital converter module of the main control microcontroller for current closed-loop control of the permanent magnet synchronous motor. On the other hand, it is sent to the COMP comparator module to detect whether an overcurrent has occurred. When an overcurrent occurs, the error signal generated by the COMP comparator module is sent to the Timer module, causing the PWM to stop emitting waves and protecting the IGBT. The external safety circuit is used to monitor the execution of the ADC interrupt service function of the main control microcontroller.

2. The circuit according to claim 1, characterized in that... Both the OPAMP operational amplifier module and the COMP comparator module are built into the main control microcontroller.

3. The circuit according to claim 1, characterized in that... The reference voltage of the OPAMP operational amplifier module is generated by the microcontroller's DAC digital-to-analog converter module.

4. The circuit according to claim 1, characterized in that... The external safety circuit includes a first transistor Q1, a second transistor Q2, a first resistor R1, a second resistor R2, a third resistor R3, a first diode D1, a second diode D2, a first capacitor C1, and a second capacitor C2. The I / O interface of the main control microcontroller is connected to the base of the first transistor Q1, the emitter of the first transistor Q1 is grounded, and the collector of the first transistor Q1 is connected to the power supply voltage of the main control microcontroller through the first resistor R1. The collector of the first transistor Q1 is also connected sequentially to the anode of the first capacitor C1 and the first diode D1. The cathode of the first diode D1 is connected to the base of the second transistor Q2, the collector of the second transistor Q2 is grounded, and the emitter of the second transistor Q2 is connected to the interrupt port NMI of the main control microcontroller on one hand, and to the power supply voltage of the main control microcontroller on the other hand through the third resistor R3. The base of the second transistor Q2 is grounded through the parallel connection of the second capacitor C2 and the second resistor R2. The anode of the first diode D1 is also connected to the cathode of the second diode D2, and the anode of the second diode D2 is grounded.

5. The circuit according to claim 4, characterized in that... The first transistor Q1 is an NPN transistor, and the second transistor Q2 is a PNP transistor.

6. The circuit according to claim 4, characterized in that... The first resistor R1 is 1kΩ, the second resistor R2 is 100kΩ, and the third resistor R3 is 10kΩ.

7. The circuit according to claim 4, characterized in that... The first capacitor C1 has a capacitance of 1 μF, and the second capacitor C2 has a capacitance of 0.1 μF.

8. The circuit according to claim 4, characterized in that... The first diode D1 and the second diode D2 are BAT54 Schottky diodes.

9. The circuit according to claim 4, characterized in that... The operation of the external safety circuit is as follows: S1. When the high and low levels of the main control microcontroller's IO port are toggled in the interrupt of the ADC analog-to-digital conversion module, a PWM waveform with a 50% duty cycle is formed, denoted as signal IO_Sim_PWM. Signal IO_Sim_PWM causes the first transistor Q1 to be intermittently turned on and off, and the collector voltage of the first transistor Q1 is a square wave signal with a low level of 0V and a high level of 3.3V. S2. The square wave voltage signal of the collector of the first transistor Q1 is rectified by the half-wave rectifier circuit composed of the first capacitor C1, the first diode D1, and the second diode D2, and forms a voltage of 3.3V as the base voltage of the second diode Q2. S3, Monitoring Status: 1) When the ADC interrupt service function of the main control microcontroller is executed normally, the base voltage of the second diode Q2 is 3.3V. The base voltage of Q2 is the same as the emitter voltage. Q2 is not conducting and is in the cutoff state. Fault_Out is high level 3.3V. 2) When the ADC interrupt service function of the main control microcontroller is executed abnormally or enters an error state, the base voltage of the second diode Q2 is 0V. Since the base voltage of Q2 is lower than the emitter voltage, Q2 is turned on, and Fault_Out is low level 0V. The IO_Sim_PWM signal of the main control microcontroller is toggled to monitor the normal execution of the ADC interrupt service function. When a microcontroller error occurs, Fault_Out can stop the permanent magnet synchronous motor from generating waves or reset and restart the microcontroller, thereby protecting the IGBT and the main control microcontroller.

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