CN103997198B - The short time voltage of converter is interrupted immunity to interference and is promoted circuit and converter - Google Patents
The short time voltage of converter is interrupted immunity to interference and is promoted circuit and converter Download PDFInfo
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- CN103997198B CN103997198B CN201410196956.3A CN201410196956A CN103997198B CN 103997198 B CN103997198 B CN 103997198B CN 201410196956 A CN201410196956 A CN 201410196956A CN 103997198 B CN103997198 B CN 103997198B
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Abstract
The short time voltage that the invention discloses a kind of converter interrupts immunity to interference lifting circuit and converter, and short time voltage is interrupted immunity to interference lifting circuit and included communication power supply input, charging circuit, rectification circuit, pfc circuit, electrochemical capacitor, inverter circuit, supply voltage break period testing circuit and controller.The short interruptions time of the alternating supply voltage that communication power supply input is inputted is detected by supply voltage break period testing circuit, and output detections result is to controller, controller is according to the testing result received, export corresponding control signal, control the charging circuit charging work to electrochemical capacitor.The present invention can suppress supply voltage again to dash current produced when electrochemical capacitor is charged circuit effectively after short interruptions to recovery is normal, the short time voltage improving converter interrupts immunity to interference level, thus improve the reliability of converter, further, the advantage that the present invention also has low cost.
Description
Technical Field
The invention relates to the technical field of frequency converters, in particular to a voltage short-time interruption immunity enhancing circuit of a frequency converter and the frequency converter.
Background
The phenomenon of short-time voltage interruption is a common power quality problem, according to the definition of GB/T17626.11, short-time voltage interruption refers to that a power supply voltage disappears for a period of time, generally not more than 1 minute, the short-time voltage interruption can be regarded as voltage dip with 100% amplitude, if the short-time voltage interruption is improper, the normal operation of electric equipment can be directly influenced, even the electric equipment can be damaged, and therefore the electric equipment is required to have higher voltage short-time interruption anti-interference capability.
When the frequency converter is in a full-load operation state, short-time interruption of the power supply voltage of the frequency converter can cause electric energy stored in an electrolytic capacitor in the frequency converter to be quickly consumed, and when the power supply voltage recovers to be normally supplied, the electrolytic capacitor needs to be recharged and stored with the electric energy. At present, the voltage interruption immunity level of the frequency converter is generally raised by increasing the positive peak surge current or the rated short-time withstand current of the device, but the method needs to be relatively expensive.
Disclosure of Invention
The invention mainly aims to provide a voltage short-time interruption immunity enhancing circuit of a frequency converter, aiming at enhancing the voltage short-time interruption immunity level of the frequency converter on the premise of lower cost so as to enhance the reliability of the frequency converter.
In order to achieve the above object, the present invention provides a voltage short-time interruption immunity boosting circuit of a frequency converter, which comprises an input terminal of an ac power supply, a charging circuit, a rectifying circuit, a PFC circuit, an electrolytic capacitor, an inverter circuit, a power supply voltage interruption time detection circuit, and a controller,
the input end of the alternating current power supply is used for inputting alternating current power supply voltage;
the charging circuit is used for charging the electrolytic capacitor;
the rectifying circuit is used for rectifying the alternating current power supply voltage and outputting a direct current voltage;
the PFC circuit is used for improving the power factor of the frequency converter;
the inverter circuit is used for inverting the direct-current voltage to be inverted into an alternating-current power supply with adjustable frequency and voltage and supplying power to a load;
the power supply voltage interruption time detection circuit is used for detecting the interruption time of the alternating current power supply voltage input by the input end of the alternating current power supply;
and the controller is used for outputting a corresponding control signal according to the detection result of the power supply voltage interruption time detection circuit and controlling the charging circuit to charge the electrolytic capacitor.
Preferably, the ac power supply input terminal includes a first ac input terminal and a second ac input terminal; the input end of the rectifying circuit comprises a first input end and a second input end; the charging circuit is connected between a first alternating current input end of the alternating current power supply input end and a first input end of the rectifying circuit; a second alternating current input end of the alternating current power supply input end is connected with a second input end of the rectifying circuit; the PFC circuit is connected between the output end of the rectification circuit and the input end of the inverter circuit; the anode of the electrolytic capacitor is connected with the anode of the input end of the inverter circuit, and the cathode of the electrolytic capacitor is connected with the cathode of the input end of the inverter circuit; the output end of the inverter circuit is connected with the power input end of the load; the detection input end of the power supply voltage interruption time detection circuit is connected with the first alternating current input end and the second alternating current input end of the alternating current power supply input end, and the detection output end of the power supply voltage interruption time detection circuit is connected with the control input end of the controller; and the control output end of the controller is connected with the charging circuit.
Preferably, the charging circuit comprises a first switch, a second switch and a charging resistor; wherein,
the first end of the first switch is connected with the first alternating current input end of the alternating current power supply input end, and the second end of the first switch is connected with the first input end of the rectifying circuit; a first end of the charging resistor is connected with a first end of the first switch, a second end of the charging resistor is connected with a first end of the second switch, and a second end of the second switch is connected with a second end of the first switch; the control end of the first switch and the control end of the second switch are both connected with the controller.
Preferably, the charging circuit further comprises a direct-current voltage detection circuit, the direct-current voltage detection circuit is used for detecting the voltage at two ends of the electrolytic capacitor and outputting a detection result to the controller, and the controller outputs a corresponding control signal according to the detection result of the direct-current voltage detection circuit and the detection result of the power supply voltage interruption time detection circuit to control the charging circuit to charge the electrolytic capacitor.
Preferably, the dc voltage detection circuit includes a first detection input terminal, a second detection input terminal, and a detection output terminal, the first detection input terminal is connected to the anode of the electrolytic capacitor, the second detection input terminal is connected to the cathode of the electrolytic capacitor, and the detection output terminal of the dc voltage detection circuit is connected to the controller.
Preferably, the power supply voltage interruption time detection circuit is a zero-cross detection circuit.
The invention also provides a voltage short-time interruption immunity enhancing circuit of the frequency converter, which comprises an input end of an alternating current power supply, a charging circuit, a rectifying circuit, a PFC circuit, an electrolytic capacitor, an inverter circuit, a direct current voltage detecting circuit and a controller, wherein,
the input end of the alternating current power supply is used for inputting alternating current power supply voltage;
the charging circuit is used for charging the electrolytic capacitor;
the rectifying circuit is used for rectifying the alternating current power supply voltage input by the input end of the alternating current power supply and outputting a direct current voltage;
the PFC circuit is used for improving the power factor of the frequency converter;
the inverter circuit is used for inverting the direct-current voltage output by the rectifying circuit, inverting the direct-current voltage into an alternating-current power supply with adjustable frequency and voltage, and supplying power to a load;
the direct-current voltage detection circuit is used for detecting the voltage at two ends of the electrolytic capacitor and outputting the detection result to the controller;
and the controller is used for outputting a corresponding control signal according to the detection result of the direct-current voltage detection circuit and controlling the charging circuit to charge the electrolytic capacitor.
Preferably, the ac power supply input terminal includes a first ac input terminal and a second ac input terminal; the input end of the rectifying circuit comprises a first input end and a second input end; the charging circuit is connected between a first alternating current input end of the alternating current power supply input end and a first input end of the rectifying circuit; a second alternating current input end of the alternating current power supply input end is connected with a second input end of the rectifying circuit; the PFC circuit is connected between the output end of the rectification circuit and the input end of the inverter circuit; the anode of the electrolytic capacitor is connected with the anode of the input end of the inverter circuit, and the cathode of the electrolytic capacitor is connected with the cathode of the input end of the inverter circuit; the output end of the inverter circuit is connected with the power input end of the load; the direct-current voltage detection circuit comprises a first detection input end, a second detection input end and a detection output end, wherein the first detection input end is connected with the anode of the electrolytic capacitor, the second detection input end is connected with the cathode of the electrolytic capacitor, and the detection output end is connected with the controller; and the control output end of the controller is connected with the charging circuit.
Preferably, the charging circuit comprises a first switch, a second switch and a charging resistor, wherein,
the first end of the first switch is connected with the first alternating current input end of the alternating current power supply input end, and the second end of the first switch is connected with the first input end of the rectifying circuit; a first end of the charging resistor is connected with a first end of the first switch, a second end of the charging resistor is connected with a first end of the second switch, and a second end of the second switch is connected with a second end of the first switch; the control end of the first switch and the control end of the second switch are both connected with the controller.
The invention also provides a frequency converter, which comprises a voltage short-time interruption immunity boosting circuit, wherein the voltage short-time interruption immunity boosting circuit comprises an alternating current power supply input end, a charging circuit, a rectifying circuit, a PFC circuit, an electrolytic capacitor, an inverter circuit, a power supply voltage interruption time detection circuit and a controller,
the input end of the alternating current power supply is used for inputting alternating current power supply voltage;
the charging circuit is used for charging the electrolytic capacitor;
the rectifying circuit is used for rectifying the alternating current power supply voltage and outputting a direct current voltage;
the PFC circuit is used for improving the power factor of the frequency converter;
the inverter circuit is used for inverting the direct-current voltage to be inverted into an alternating-current power supply with adjustable frequency and voltage and supplying power to a load;
the power supply voltage interruption time detection circuit is used for detecting the interruption time of the alternating current power supply voltage input by the input end of the alternating current power supply;
and the controller is used for outputting a corresponding control signal according to the detection result of the power supply voltage interruption time detection circuit and controlling the charging circuit to charge the electrolytic capacitor.
The invention provides a voltage short-time interruption immunity improving circuit of a frequency converter, which comprises an alternating current power supply input end, a charging circuit, a rectifying circuit, a PFC circuit, an electrolytic capacitor, an inverter circuit, a power supply voltage interruption time detection circuit and a controller. The input end of the alternating current power supply is used for inputting alternating current power supply voltage; the charging circuit is used for charging the electrolytic capacitor; the rectifying circuit is used for rectifying the alternating current power supply voltage and outputting a direct current voltage; the PFC circuit is used for improving the power factor of the frequency converter; the inverter circuit is used for inverting the direct-current voltage output by the rectifying circuit to be inverted into an alternating-current power supply with adjustable frequency and voltage to supply power to a load; the power supply voltage interruption time detection circuit is used for detecting the interruption time of the alternating current power supply voltage input by the input end of the alternating current power supply; the controller is used for outputting a corresponding control signal according to the detection result of the power supply voltage interruption time detection circuit and controlling the charging circuit to charge the electrolytic capacitor. The invention can effectively restrain the impact current generated when the electrolytic capacitor in the circuit is recharged after the power supply voltage is recovered from short-time interruption to normal, and improves the voltage short-time interruption immunity level of the frequency converter, thereby improving the reliability of the frequency converter, and the invention also has the advantage of low cost.
Drawings
FIG. 1 is a circuit diagram of a first embodiment of a voltage short interruption immunity boosting circuit of a frequency converter according to the present invention;
FIG. 2 is a circuit diagram of a second embodiment of the voltage short interruption immunity boosting circuit of the frequency converter according to the present invention;
FIG. 3 is a circuit diagram of a third embodiment of the voltage short interruption immunity boosting circuit of the frequency converter according to the present invention;
fig. 4 is a circuit diagram of a fourth embodiment of the voltage short-interruption immunity boosting circuit of the frequency converter of the present invention.
The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.
Detailed Description
It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The invention provides a voltage short-time interruption immunity enhancing circuit of a frequency converter. Fig. 1 is a circuit diagram of a first embodiment of a voltage short-interruption immunity boosting circuit of a frequency converter according to the present invention.
Referring to fig. 1, the voltage short-time interruption immunity boosting circuit of the frequency converter in the present embodiment includes an ac power supply input terminal 101, a charging circuit 102, a rectifying circuit 103, a PFC circuit 104, an electrolytic capacitor E1, an inverter circuit 105, a power supply voltage interruption time detection circuit 106, and a controller 107. Wherein,
an ac power supply input terminal 101 for inputting an ac power supply voltage;
a charging circuit 102 for charging the electrolytic capacitor E1;
the rectifying circuit 103 is used for rectifying the alternating-current power supply voltage input by the alternating-current power supply input end 101 and outputting a direct-current voltage;
a PFC circuit 104 for improving the power factor of the frequency converter;
the inverter circuit 105 is used for inverting the direct-current voltage output by the rectifier circuit 103, inverting the direct-current voltage into an alternating-current power supply with adjustable frequency and voltage, and supplying power to the load 200;
a power supply voltage interruption time detection circuit 106 for detecting the interruption time of the ac power supply voltage input from the ac power supply input terminal 101;
and the controller 107 is configured to output a corresponding control signal according to a detection result of the supply voltage interruption time detection circuit 106, and control the charging operation of the charging circuit 102 on the electrolytic capacitor E1.
The power supply voltage interruption time detection circuit 106 in this embodiment is a zero-crossing detection circuit.
Specifically, the ac power supply input terminal 101 includes a first ac input terminal a and a second ac input terminal b; the input terminals of the rectifier circuit 103 include a first input terminal c and a second input terminal d; the charging circuit 102 is connected between a first alternating current input end a of the alternating current power supply input end 101 and a first input end c of the rectifying circuit 103; the PFC circuit 104 is connected between the output end of the rectification circuit 103 and the input end of the inverter circuit 105; the anode of the electrolytic capacitor E1 is connected with the anode of the input end of the inverter circuit 105, and the cathode of the electrolytic capacitor E1 is connected with the cathode of the input end of the inverter circuit 105; the output end of the inverter circuit 105 is connected with the power input end of the load 200; a detection input end of the power supply voltage interruption time detection circuit 106 is connected with a first alternating current input end a and a second alternating current input end b of the alternating current power supply input end 101, and a detection output end of the power supply voltage interruption time detection circuit 106 is connected with a control input end of the controller 107; a control output of the controller 107 is connected to the charging circuit 102.
The charging circuit 102 includes a first switch K1, a second switch K2, and a charging resistor R1. Specifically, a first terminal of the first switch K1 is connected to the first ac input terminal a of the ac power supply input terminal 101, and a second terminal of the first switch K1 is connected to the first input terminal c of the rectifier circuit 103; a first end of the charging resistor R1 is connected with a first end of the first switch K1, a second end of the charging resistor R1 is connected with a first end of the second switch K2, and a second end of the second switch K2 is connected with a second end of the first switch K1; the control terminal of the first switch K1 and the control terminal of the second switch K2 are both connected to the controller 107.
The PFC circuit 104 includes an inductor L1, a diode D1, and an IGBT Q1. The first end of the inductor L1 is connected with the positive pole of the output end of the rectifying circuit 103, the second end of the inductor L1 is connected with the positive pole of the diode D1, the cathode of the diode D1 is connected with the positive pole of the input end of the inverter circuit 105, the collector of the IGBT tube Q1 is connected between the inductor L1 and the diode D1, the emitter of the IGBT tube Q1 is connected with the negative pole of the output end of the rectifying circuit 103, and the control signal PWM1 input to the gate of the IGBT tube Q1 controls the on-time and the off-time of the IGBT tube Q1, so that the power factor of the frequency converter is improved.
In this embodiment, when the ac power supply voltage at the ac power supply input terminal 101 is just switched on, the controller 107 outputs a corresponding control signal to control the first switch K1 to be in an off state and the second switch K2 to be in an on state, the ac power supply voltage charges the electrolytic capacitor E1 through the charging resistor R1, the rectifying circuit 103 and the PFC circuit 104, and after the electrolytic capacitor E1 is charged to a certain value, the controller 107 outputs a corresponding control signal to close the first switch K1 and switch the second switch K2 off, thereby completing the precharging process of the electrolytic capacitor E1. The branch in which the first switch K1 is located then always takes over the task of supplying power to the load 200.
The specific working principle of this embodiment is described as follows: the power supply voltage interruption time detection circuit 106 detects the time of the instantaneous interruption of the alternating current power supply voltage at the alternating current power supply input end 101, when the time of the continuous interruption of the alternating current power supply voltage is detected to exceed the preset time nT (T is 1/f, f is the frequency of the input alternating current power supply voltage), the frequency converter stops working, the controller 107 outputs corresponding control signals to the control end of the first switch K1 and the control end of the second switch K2 to control the first switch K1 to be opened and the second switch K2 to be closed, therefore, when the alternating current power supply voltage at the alternating current power supply input end 101 returns to the normal power supply, the electrolytic capacitor E1 is charged through the charging resistor R1 in the branch where the second switch K2 is located, when the time of the alternating current power supply voltage at the alternating current power supply input end 101 returning to the normal power supply reaches the preset time mT, the controller 107 sends corresponding control signals to the control end of the first switch K1 and the control end of the second switch K2, the first switch K1 is controlled to be closed, the second switch K2 is controlled to be opened, so that the branch where the first switch K1 is located supplies power to the load 200, and the frequency converter recovers to work. In the embodiment, the interruption time of the ac power supply voltage input from the ac power supply input terminal 101 is detected by the power supply voltage interruption time detection circuit 106, and the detection result is output to the controller 107, the controller 107 outputs a corresponding control signal according to the detection result of the power supply voltage interruption time detection circuit 106, and controls the first switch K1 to be opened and the second switch K2 to be closed, so that the branch where the second switch K2 is located (i.e., the branch where the charging resistor R1 is located) charges the electrolytic capacitor E1, thereby effectively suppressing the impact current generated when the electrolytic capacitor E1 is recharged after the power supply voltage is interrupted from a short time to a normal state, thereby improving the voltage short-time interruption immunity level of the frequency converter, and achieving the purpose of improving the reliability of the frequency converter.
The voltage short-time interruption immunity improving circuit of the frequency converter provided by the embodiment comprises an alternating current power supply input end, a charging circuit, a rectifying circuit, a PFC circuit, an electrolytic capacitor, an inverter circuit, a power supply voltage interruption time detection circuit and a controller. The input end of the alternating current power supply is used for inputting alternating current power supply voltage; the charging circuit is used for charging the electrolytic capacitor; the rectification circuit is used for rectifying the alternating current power supply voltage and outputting a direct current power supply; the PFC circuit is used for improving the power factor of the frequency converter; the inverter circuit is used for inverting the direct-current voltage output by the rectifying circuit to be inverted into an alternating-current power supply with adjustable frequency and voltage to supply power to a load; the power supply voltage interruption time detection circuit is used for detecting the interruption time of the alternating current power supply voltage input by the input end of the alternating current power supply; the controller is used for outputting a corresponding control signal according to the detection result of the power supply voltage interruption time detection circuit and controlling the charging circuit to charge the electrolytic capacitor. The invention can effectively restrain the impact current generated when the electrolytic capacitor in the circuit is recharged after the power supply voltage is recovered from short-time interruption to normal, and improves the voltage short-time interruption immunity level of the frequency converter, thereby improving the reliability of the frequency converter, and the invention also has the advantage of low cost.
Fig. 2 is a circuit diagram of a second embodiment of the voltage short-interruption immunity boosting circuit of the frequency converter of the present invention.
Referring to fig. 2, the present embodiment further includes a dc voltage detection circuit 108 in addition to the first embodiment, the dc voltage detection circuit 108 is configured to detect the voltage across the electrolytic capacitor E1 and output the detection result to the controller 107, and the controller 107 outputs a corresponding control signal according to the detection result of the dc voltage detection circuit 108 and the detection result of the supply voltage interruption time detection circuit 106, so as to control the charging operation of the charging circuit 102 on the electrolytic capacitor E1.
The direct-current voltage detection circuit 108 comprises a first detection input end E, a second detection input end f and a detection output end, the first detection input end E of the direct-current voltage detection circuit 108 is connected with the positive electrode of the electrolytic capacitor E1, the second detection input end f of the direct-current voltage detection circuit 108 is connected with the negative electrode of the electrolytic capacitor E1, and the detection output end of the direct-current voltage detection circuit 108 is connected with the corresponding control input end of the controller 107.
In this embodiment, when the voltage value across the electrolytic capacitor E1 is reduced to below the preset threshold value VLIMIT1, the frequency converter stops working, the controller 107 outputs corresponding control signals to the control end of the first switch K1 and the control end of the second switch K2, controls the first switch K1 to be opened, controls the second switch K2 to be closed, charges the electrolytic capacitor E1 through the charging resistor R1 in the branch where the second switch K2 is located, and after the voltage value across the electrolytic capacitor E1 is restored to above the preset threshold value VLIMIT2 and lasts for a certain time, the controller 107 sends corresponding control signals to the control end of the first switch K1 and the control end of the second switch K2, controls the first switch K1 to be closed, controls the second switch K2 to be opened, so that the branch where the first switch K1 is located supplies power to the load 200, and the frequency converter resumes working.
The specific working principle of this embodiment is described as follows: in this embodiment, the power supply voltage interruption time detection circuit 106 detects the interruption time of the ac power supply voltage input from the ac power supply input terminal 101, and outputs the detection result to the controller 107, and the dc voltage detection circuit 108 detects the voltage across the electrolytic capacitor E1, and outputs the detection result to the controller 107, so that the controller 107 outputs a corresponding control signal according to the detection result of the power supply voltage interruption time detection circuit 106 and the detection result of the dc voltage detection circuit 108, and controls the charging process of the electrolytic capacitor E1 by the charging circuit 102.
Specifically, when the supply voltage interruption time detection circuit 106 detects that the duration time of the ac supply voltage interruption exceeds the preset time nT (T is 1/f, and f is the frequency of the input ac supply voltage), or when the dc voltage detection circuit 108 detects that the voltage value at the two ends of the electrolytic capacitor E1 is reduced to be less than or equal to the preset threshold value VLIMIT1, the frequency converter stops working, the controller 107 outputs a corresponding control signal to control the first switch K1 to be opened and the second switch K2 to be closed, so that the electrolytic capacitor E1 is charged by the branch where the second switch K2 is located (i.e., the branch where the charging resistor R1 is located), thereby effectively suppressing the impact current generated when the electrolytic capacitor E1 is charged, and improving the voltage short-time interruption immunity level of the frequency converter, thereby achieving the purpose of improving the reliability of the frequency converter.
The voltage short-time interruption immunity improving circuit of the frequency converter provided by the embodiment comprises an alternating current power supply input end, a charging circuit, a rectifying circuit, a PFC circuit, an electrolytic capacitor, an inverter circuit, a power supply voltage interruption time detection circuit, a direct current voltage detection circuit and a controller. The input end of the alternating current power supply is used for inputting alternating current power supply voltage; the charging circuit is used for charging the electrolytic capacitor; the rectifying circuit is used for rectifying the alternating current power supply voltage and outputting a direct current voltage; the PFC circuit is used for improving the power factor of the frequency converter; the inverter circuit is used for inverting the direct-current voltage output by the rectifying circuit to be inverted into an alternating-current power supply with adjustable frequency and voltage to supply power to a load; the power supply voltage interruption time detection circuit is used for detecting the interruption time of the alternating current power supply voltage input by the input end of the alternating current power supply; the direct-current voltage detection circuit is used for detecting the voltage at two ends of the electrolytic capacitor and outputting a detection result to the controller; the controller outputs a corresponding control signal according to the detection result of the direct-current voltage detection circuit and the detection result of the power supply voltage interruption time detection circuit, and controls the charging circuit to charge the electrolytic capacitor. The invention can effectively restrain the impact current generated when the electrolytic capacitor in the circuit is recharged after the power supply voltage is recovered from short-time interruption to normal, and improves the voltage short-time interruption immunity level of the frequency converter, thereby improving the reliability of the frequency converter, and the invention also has the advantage of low cost.
Fig. 3 is a circuit diagram of a third embodiment of the voltage short-interruption immunity boosting circuit of the frequency converter of the present invention.
Referring to fig. 3, the voltage short-time interruption immunity boosting circuit of the frequency converter in the present embodiment includes an ac power supply input terminal 201, a charging circuit 202, a rectifying circuit 203, a PFC circuit 204, an electrolytic capacitor E1, an inverter circuit 205, a dc voltage detection circuit 206, and a controller 207. Wherein,
an ac power supply input terminal 201 for inputting an ac power supply voltage;
a charging circuit 202 for charging the electrolytic capacitor E2;
the rectifying circuit 203 is used for rectifying the alternating current power supply voltage input by the alternating current power supply input end 201 and outputting a direct current voltage;
the PFC circuit 204 is used for improving the power factor of the frequency converter;
the inverter circuit 205 is configured to invert the dc voltage output by the rectifier circuit 203, so as to convert the dc voltage into an ac power supply with adjustable frequency and voltage, and supply power to the load 300;
a dc voltage detection circuit 206 for detecting a voltage across the electrolytic capacitor E2 and outputting a detection result to the controller 207;
the controller 207 is configured to output a corresponding control signal according to the detection result of the dc voltage detection circuit 206, and control the charging operation of the charging circuit 202 on the electrolytic capacitor E1.
Specifically, the ac power supply input terminal 201 includes a first ac input terminal a1 and a second ac input terminal b 1; the input terminals of the rectifier circuit 203 include a first input terminal c1 and a second input terminal d 1; the charging circuit 202 is connected between the first ac input terminal a1 of the ac power supply input terminal 201 and the first input terminal c1 of the rectifying circuit 203; the PFC circuit 204 is connected between the output terminal of the rectifier circuit 203 and the input terminal of the inverter circuit 205; the positive electrode of the electrolytic capacitor E2 is connected with the positive electrode of the input end of the inverter circuit 205, and the negative electrode of the electrolytic capacitor E2 is connected with the negative electrode of the input end of the inverter circuit 205; the output end of the inverter circuit 205 is connected with the power input end of the load 300; the direct-current voltage detection circuit 206 comprises a first detection input end E1, a second detection input end f1 and a detection output end, the first detection input end E1 of the direct-current voltage detection circuit 206 is connected with the positive electrode of the electrolytic capacitor E2, the second detection input end f1 of the direct-current voltage detection circuit 206 is connected with the negative electrode of the electrolytic capacitor E2, and the detection output end of the direct-current voltage detection circuit 206 is connected with the corresponding control input end of the controller 207; a control output of the controller 207 is connected to the charging circuit 202.
The charging circuit 202 includes a first switch K3, a second switch K4, and a charging resistor R2. Specifically, a first terminal of the first switch K3 is connected to the first ac input terminal a1 of the ac power supply input terminal 201, and a second terminal of the first switch K3 is connected to the first input terminal c1 of the rectifier circuit 203; a first end of the charging resistor R2 is connected with a first end of the first switch K3, a second end of the charging resistor R2 is connected with a first end of the second switch K4, and a second end of the second switch K4 is connected with a second end of the first switch K3; the control terminal of the first switch K3 and the control terminal of the second switch K4 are both connected to the controller 207.
The PFC circuit 204 includes an inductor L2, a diode D2, and an IGBT Q2. The first end of the inductor L2 is connected with the positive electrode of the output end of the rectifying circuit 203, the second end of the inductor L2 is connected with the positive electrode of the diode D2, the cathode of the diode D2 is connected with the positive electrode of the input end of the inverter circuit 205, the collector of the IGBT tube Q2 is connected between the inductor L2 and the diode D2, the emitter of the IGBT tube Q2 is connected with the negative electrode of the output end of the rectifying circuit 203, and the control signal PWM2 input to the gate of the IGBT tube Q2 controls the on-time and the off-time of the IGBT tube Q2, so that the power factor of the frequency converter is improved.
The specific working principle of this embodiment is as follows: when the voltage value of the two ends of the electrolytic capacitor E2 is reduced to be below a preset threshold value VLIMIT3, the frequency converter stops working, the controller 207 outputs corresponding control signals to the control end of the first switch K3 and the control end of the second switch K4, controls the first switch K3 to be opened and the second switch K4 to be closed, charges the electrolytic capacitor E2 through the charging resistor R2 in the branch where the second switch K4 is located, and after the voltage value of the two ends of the electrolytic capacitor E2 is restored to be above the preset threshold value VLIMIT4 and continues for a certain time, the controller 207 sends corresponding control signals to the control end of the first switch K3 and the control end of the second switch K4, controls the first switch K3 to be closed and the second switch K4 to be opened, so that the branch where the first switch K3 is located supplies power to the load 300, and the frequency converter restores working. In the embodiment, the direct-current voltage detection circuit 206 detects the voltage at two ends of the electrolytic capacitor E2, and outputs the detection result to the controller 207, and the controller 207 outputs a corresponding control signal according to the detection result of the direct-current voltage detection circuit 206 to control the first switch K3 to be turned off and the second switch K4 to be turned on, so that the branch where the second switch K4 is located (i.e., the branch where the charging resistor R2 is located) charges the electrolytic capacitor E2, thereby effectively suppressing the impact current generated when the electrolytic capacitor E2 is charged, improving the voltage short-time interruption immunity level of the frequency converter, and achieving the purpose of improving the reliability of the frequency converter.
The voltage short-time interruption immunity improving circuit of the frequency converter provided by the embodiment comprises an alternating current power supply input end, a charging circuit, a rectifying circuit, a PFC circuit, an electrolytic capacitor, an inverter circuit, a direct current voltage detection circuit and a controller. The input end of the alternating current power supply is used for inputting alternating current power supply voltage; the charging circuit is used for charging the electrolytic capacitor; the rectifying circuit is used for rectifying the alternating current power supply voltage and outputting a direct current voltage; the PFC circuit is used for improving the power factor of the frequency converter; the inverter circuit inverts the direct-current voltage output by the rectifying circuit into an alternating-current power supply with adjustable frequency and voltage to supply power to a load; the direct-current voltage detection circuit is used for detecting the voltage at two ends of the electrolytic capacitor and outputting a detection result to the controller; the controller outputs corresponding control signals according to the detection result of the direct-current voltage detection circuit to control the charging circuit to charge the electrolytic capacitor. The invention can effectively restrain the impact current generated when the electrolytic capacitor in the circuit is recharged after the power supply voltage is recovered from short-time interruption to normal, and improves the voltage short-time interruption immunity level of the frequency converter, thereby improving the reliability of the frequency converter, and the invention also has the advantage of low cost.
Fig. 4 is a circuit diagram of a fourth embodiment of the voltage short-interruption immunity boosting circuit of the frequency converter of the present invention.
Referring to fig. 4, the circuit structure of the voltage short-time interruption immunity enhancing circuit of the frequency converter of the present embodiment is different from the circuit structure of the second embodiment only in that: the charging circuit 102 in the voltage short-time interruption immunity boosting circuit of the frequency converter of the present embodiment is located on the direct current side of the rectifying circuit 103, while the charging circuit 102 in the second embodiment described above is located on the alternating current side of the rectifying circuit 103. The circuit operating principle of the voltage short-time interruption immunity boosting circuit of the frequency converter of this embodiment is the same as that of the second embodiment described above, and is not described here again.
The invention further provides a frequency converter, which includes a voltage short-time interruption immunity boosting circuit, and the circuit structure and the circuit operating principle of the voltage short-time interruption immunity boosting circuit are the same as those of the voltage short-time interruption immunity boosting circuit described in the above embodiments, and are not described herein again.
The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.
Claims (10)
1. A voltage short-time interruption immunity enhancing circuit of a frequency converter is characterized by comprising an input end of an alternating current power supply, a charging circuit, a rectifying circuit, a PFC circuit, an electrolytic capacitor, an inverter circuit, a power supply voltage interruption time detection circuit and a controller, wherein,
the input end of the alternating current power supply is used for inputting alternating current power supply voltage;
the charging circuit is used for charging the electrolytic capacitor;
the rectifying circuit is used for rectifying the alternating current power supply voltage and outputting a direct current voltage;
the PFC circuit is used for improving the power factor of the frequency converter;
the inverter circuit is used for inverting the direct-current voltage to be inverted into an alternating-current power supply with adjustable frequency and voltage and supplying power to a load;
the power supply voltage interruption time detection circuit is used for detecting the interruption time of the alternating current power supply voltage input by the input end of the alternating current power supply;
and the controller is used for outputting a corresponding control signal according to the detection result of the power supply voltage interruption time detection circuit and controlling the charging circuit to charge the electrolytic capacitor.
2. The voltage short interruption immunity boost circuit of claim 1, wherein said ac power supply input terminals comprise a first ac input terminal and a second ac input terminal; the input end of the rectifying circuit comprises a first input end and a second input end; the charging circuit is connected between a first alternating current input end of the alternating current power supply input end and a first input end of the rectifying circuit; a second alternating current input end of the alternating current power supply input end is connected with a second input end of the rectifying circuit; the PFC circuit is connected between the output end of the rectification circuit and the input end of the inverter circuit; the anode of the electrolytic capacitor is connected with the anode of the input end of the inverter circuit, and the cathode of the electrolytic capacitor is connected with the cathode of the input end of the inverter circuit; the output end of the inverter circuit is connected with the power input end of the load; the detection input end of the power supply voltage interruption time detection circuit is connected with the first alternating current input end and the second alternating current input end of the alternating current power supply input end, and the detection output end of the power supply voltage interruption time detection circuit is connected with the control input end of the controller; and the control output end of the controller is connected with the charging circuit.
3. The voltage short interruption immunity to noise improvement circuit of frequency converter according to claim 2, wherein said charging circuit comprises a first switch, a second switch and a charging resistor, wherein,
the first end of the first switch is connected with the first alternating current input end of the alternating current power supply input end, and the second end of the first switch is connected with the first input end of the rectifying circuit; a first end of the charging resistor is connected with a first end of the first switch, a second end of the charging resistor is connected with a first end of the second switch, and a second end of the second switch is connected with a second end of the first switch; the control end of the first switch and the control end of the second switch are both connected with the controller.
4. The short-interruption immunity-improving circuit for voltage of frequency converter according to claim 3, further comprising a dc voltage detection circuit, wherein the dc voltage detection circuit is configured to detect a voltage across the electrolytic capacitor and output a detection result to the controller, and the controller outputs a corresponding control signal according to the detection result of the dc voltage detection circuit and the detection result of the power supply voltage interruption time detection circuit to control the charging operation of the electrolytic capacitor by the charging circuit.
5. The short-term voltage interruption immunity boosting circuit according to claim 4, wherein the DC voltage detection circuit comprises a first detection input terminal, a second detection input terminal and a detection output terminal, the first detection input terminal is connected to the positive electrode of the electrolytic capacitor, the second detection input terminal is connected to the negative electrode of the electrolytic capacitor, and the detection output terminal of the DC voltage detection circuit is connected to the controller.
6. The voltage short interruption immunity boosting circuit of frequency converter according to claim 5, wherein said power supply voltage interruption time detection circuit is a zero-crossing detection circuit.
7. A voltage short-time interruption immunity enhancing circuit of a frequency converter is characterized by comprising an input end of an alternating current power supply, a charging circuit, a rectifying circuit, a PFC circuit, an electrolytic capacitor, an inverter circuit, a direct current voltage detection circuit and a controller, wherein,
the input end of the alternating current power supply is used for inputting alternating current power supply voltage;
the charging circuit is used for charging the electrolytic capacitor;
the rectifying circuit is used for rectifying the alternating current power supply voltage input by the input end of the alternating current power supply and outputting a direct current voltage;
the PFC circuit is used for improving the power factor of the frequency converter;
the inverter circuit is used for inverting the direct-current voltage output by the rectifying circuit, inverting the direct-current voltage into an alternating-current power supply with adjustable frequency and voltage, and supplying power to a load;
the direct-current voltage detection circuit is used for detecting the voltage at two ends of the electrolytic capacitor and outputting the detection result to the controller;
and the controller is used for outputting a corresponding control signal according to the detection result of the direct-current voltage detection circuit and controlling the charging circuit to charge the electrolytic capacitor.
8. The voltage short interruption immunity boost circuit of claim 7, wherein said ac power supply input terminals comprise a first ac input terminal and a second ac input terminal; the input end of the rectifying circuit comprises a first input end and a second input end; the charging circuit is connected between a first alternating current input end of the alternating current power supply input end and a first input end of the rectifying circuit; a second alternating current input end of the alternating current power supply input end is connected with a second input end of the rectifying circuit; the PFC circuit is connected between the output end of the rectification circuit and the input end of the inverter circuit; the anode of the electrolytic capacitor is connected with the anode of the input end of the inverter circuit, and the cathode of the electrolytic capacitor is connected with the cathode of the input end of the inverter circuit; the output end of the inverter circuit is connected with the power input end of the load; the direct-current voltage detection circuit comprises a first detection input end, a second detection input end and a detection output end, wherein the first detection input end is connected with the anode of the electrolytic capacitor, the second detection input end is connected with the cathode of the electrolytic capacitor, and the detection output end is connected with the controller; and the control output end of the controller is connected with the charging circuit.
9. The voltage short interruption immunity to noise improvement circuit of frequency converter according to claim 8, wherein said charging circuit comprises a first switch, a second switch and a charging resistor, wherein,
the first end of the first switch is connected with the first alternating current input end of the alternating current power supply input end, and the second end of the first switch is connected with the first input end of the rectifying circuit; a first end of the charging resistor is connected with a first end of the first switch, a second end of the charging resistor is connected with a first end of the second switch, and a second end of the second switch is connected with a second end of the first switch; the control end of the first switch and the control end of the second switch are both connected with the controller.
10. A frequency converter, characterized by comprising a voltage short-break immunity boosting circuit of a frequency converter according to any one of claims 1 to 9.
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| CN104898511B (en) * | 2015-05-05 | 2018-07-10 | 广东美的暖通设备有限公司 | The method and apparatus for improving the noise immunity of electric-controlled plate in electrical equipment |
| CN104991110B (en) * | 2015-06-26 | 2017-12-12 | 广东美的制冷设备有限公司 | The electric voltage exception detection method and device of single phase alternating current power supply |
| CN105024539B (en) * | 2015-06-26 | 2017-11-10 | 广东美的制冷设备有限公司 | The short time voltage of single phase alternating current power supply interrupts countermeasure and device |
| CN107990505A (en) * | 2017-12-21 | 2018-05-04 | 广东美的暖通设备有限公司 | Frequency conversion control circuit and air conditioner |
| CN108199572B (en) * | 2017-12-25 | 2021-03-30 | 苏州英威腾电力电子有限公司 | Frequency converter and power-off protection system thereof |
| CN108832703A (en) * | 2018-06-14 | 2018-11-16 | 珠海格力电器股份有限公司 | Capacitor charging circuit, air conditioner and control method |
| CN108650764A (en) * | 2018-07-12 | 2018-10-12 | 青岛亿联客信息技术有限公司 | Switch detection circuit and lamps and lanterns |
| CN109950879B (en) * | 2019-02-28 | 2020-05-19 | 珠海格力电器股份有限公司 | Charging protection device and method for power utilization circuit and circuit with charging protection function |
| CN112968596B (en) * | 2021-02-24 | 2022-10-18 | 广东美的暖通设备有限公司 | Frequency converter and control method of contactor thereof |
| CN112909885B (en) * | 2021-03-03 | 2023-01-24 | 日立楼宇技术（广州）有限公司 | Control method and device of variable frequency control circuit, computer equipment and storage medium |
| CN114665758B (en) * | 2022-05-25 | 2022-09-02 | 中山大洋电机股份有限公司 | Permanent magnet motor system and soft start method |
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