DC surge absorption circuit and motor controller

Abstract

The DC surge absorption circuit is characterized in that after a capacitor C1, a surge charging diode D2 and a capacitor C3 are connected in series, two ends of the capacitor C1, the surge charging diode D2 and the capacitor C3 are respectively connected with a DC output end A and a grounding end PGND of a rectification circuit, and two ends of the capacitor C1 are respectively connected with the DC output end A and an anode of the surge charging diode D2; the two ends of the capacitor C3 are connected with the negative electrode of the surge charging diode D2 and the grounding end PGND respectively, the positive electrode of the power-down discharging diode D1 is connected with the negative electrode of the surge charging diode D2, and the negative electrode of the power-down discharging diode D1 is connected with the direct current output end A; the positive electrode of the power-down discharge diode D3 is connected with the grounding end PGND, the negative electrode of the power-down discharge diode D3 is connected with the positive electrode of the surge charge diode D2, the piezoresistor VAR1 and the discharge resistor R1 are connected in parallel to the two ends of the capacitor C1 respectively, and the piezoresistor VAR2 and the discharge resistor R2 are connected in parallel to the two ends of the capacitor C3 respectively. And voltage fluctuation is reduced and working stability is improved.

Description

Technical field:

[0001] The utility model relates to a direct current surge absorption circuit and a motor controller. Background technology:

[0002] Since most DC motors' DC power supply comes from the mains, which is basically obtained through mains rectification and capacitor filtering, there will be surge problems when the motor circuit is connected to the mains grid. The reason is that there are various loads on the same grid, such as capacitive loads, resistive loads, inductive loads, etc. At the same time, there is lightning. The grid is very bad, and the instantaneous surge voltage can reach thousands of volts or even higher, which will cause the risk of permanent failure of the motor (such as Figure 1 middle curve); therefore, to address this problem, we choose to use varistor as a component to absorb surge voltage or other application circuits for surge absorption, resulting in various application circuits specifically for surge absorption, referred to as DC surge absorption circuits.

[0003] There are two common application circuits of DC surge absorption circuits, see Figure 2 , Figure 3 As shown, the above two DC surge absorption circuits have the following inevitable defects:

[0004] Figure 2 In the DC surge absorption circuit, when the motor is running, the DC voltage comes from the AC input of the mains and passes through the rectifier bridge BG11 to obtain the DC output. Since the power is taken from the mains power grid, the environment in the grid is extremely harsh and there are various loads, including capacitive loads, resistive loads, inductive loads, etc. There will also be lightning, and surge voltage exists at all times. When the power supply instantly generates a surge voltage, the varistor VAR11 absorbs it. C11 is a CBB film capacitor. If it is too high, it is easy to break down the varistor VAR1 and CBB film capacitor (the purpose of using CBB film capacitors in this motor solution is to improve the power factor. Electrolytic capacitors cannot be directly added to the +BUS and PGND terminals, otherwise they will lose their function). If the surge voltage is too high, it will cause permanent damage. The selection of the varistor VAR11 is also very important. If the voltage is too high, the surge protection function will be lost. If it is too low, it is easy to break down and can only suppress part of the surge. The selection is extremely difficult and there is also a risk of failure (such as Figure 4 The voltage is too high and will damage the rectifier module BG11 and the electronic switch tubes Q1, Q2, Q3, Q4, Q5, Q6 in the subsequent motor inverter circuit, causing damage to the motor controller.

[0005] Figure 3In the DC surge absorption circuit, when the motor is running, the DC voltage comes from the AC input of the mains and passes through the rectifier bridge BG11 to obtain the DC output. Since the power is taken from the mains power grid, the environment in the grid is extremely harsh, and there are various loads, including capacitive loads, resistive loads, inductive loads, etc. There will also be lightning, and surge voltage exists at all times. When the power supply instantly generates a surge voltage, the transient suppression discharge diode TVS1 absorbs it. C11 is a CBB film capacitor. If it is too high, it is easy to break down the varistor TVS1 or CBB film capacitor (the purpose of using CBB film capacitors in this motor solution is to improve the power factor. Electrolytic capacitors cannot be directly added to the +BUS and PGND terminals, otherwise they will lose their function). If the surge voltage is too high, it will cause permanent damage. The selection of the discharge diode TVS11 is also very important. If the voltage is too high, the surge protection function will be lost. If it is too low, it is easy to break down and can only suppress part of the surge. The selection is extremely difficult and there is also a risk of failure (such as Figure 4 The voltage is too high and will damage the rectifier module BG1 and the electronic switch tubes Q1, Q2, Q3, Q4, Q5, Q6 in the subsequent motor inverter circuit, causing damage to the motor controller. Summary of the invention:

[0006] The purpose of the utility model is to provide a DC surge absorption circuit and a motor controller, so as to solve the technical problems that the selection of components of the DC surge absorption circuit of the motor controller in the background technology is extremely difficult and there is also a risk of failure, and the components of the DC surge absorption circuit are selected with too high a voltage, which will damage the rectifier module and the subsequent motor inverter circuit, causing damage to the motor controller.

[0007] The purpose of the utility model is achieved through the following technical solutions.

[0008] A DC surge absorption circuit is connected between a DC output terminal A and a ground terminal PGND, and is characterized in that: it includes a capacitor C1, a capacitor C3, a varistor VAR1, a varistor VAR2, a discharge resistor R1, a discharge resistor R2, a surge charging diode D2, a power-off discharge diode D1 and a power-off discharge diode D3, the capacitor C1, the surge charging diode D2 and the capacitor C3 are connected in series, and the two ends are respectively connected to the DC output terminal A of the rectifier circuit and the ground terminal PGND, and the two ends of the capacitor C1 are respectively connected to the DC output terminal A and the positive terminal of the surge charging diode D2. The two ends of the capacitor C3 are connected to the cathode of the surge charging diode D2 and the ground terminal PGND respectively, the anode of the power-off discharge diode D1 is connected to the cathode of the surge charging diode D2, and the cathode of the power-off discharge diode D1 is connected to the DC output terminal A; the anode of the power-off discharge diode D3 is connected to the ground terminal PGND, and the cathode of the power-off discharge diode D3 is connected to the anode of the surge charging diode D2, the varistor VAR1 and the discharge resistor R1 are respectively connected in parallel to the two ends of the capacitor C1, and the varistor VAR2 and the discharge resistor R2 are respectively connected in parallel to the two ends of the capacitor C3.

[0009] A motor controller includes a rectifier circuit, a surge absorption circuit, a filter circuit and a motor inverter circuit. The AC input of the mains is processed by the rectifier circuit to form a DC output terminal A. The DC output terminal A is processed by the surge absorption circuit and the filter circuit to obtain a DC bus voltage Vbus. The DC bus voltage Vbus supplies power to the motor inverter circuit. It is characterized in that the surge absorption circuit is a DC surge absorption circuit as described above.

[0010] The above-mentioned rectifier circuit is the rectifier module BG1, and the filter circuit is the film capacitor C2.

[0011] A DC surge absorption circuit is connected between a DC output terminal A and a ground terminal PGND, and is characterized in that it includes a capacitor C4, a capacitor C5, a capacitor C6, a capacitor C7, a discharge resistor R3, a discharge resistor R4, a discharge resistor R5, a discharge resistor R6, a surge charging diode D4, a power-off discharge diode D5, a power-off discharge diode D6, a power-off discharge diode D7 and a power-off discharge diode D8, wherein the surge charging diode D4, the capacitor C4, the capacitor C5, the capacitor C6 and the capacitor C7 are connected in series and the two ends are respectively connected to the DC output terminal A of the rectifier circuit and the ground terminal PGND, the positive electrode of the surge charging diode D4 is connected to the DC output terminal A, the negative electrode of the surge charging diode D4 is connected to one end of the capacitor C4, and the discharge resistor R 3 is connected in parallel at both ends of the capacitor C4, the discharge resistor R4 is connected in parallel at both ends of the capacitor C5, the discharge resistor R5 is connected in parallel at both ends of the capacitor C6, the discharge resistor R6 is connected in parallel at both ends of the capacitor C7, the cathodes of the power-off discharge diode D5, the power-off discharge diode D6, the power-off discharge diode D7 and the power-off discharge diode D8 are all connected to the DC output terminal A, the node H1 between the surge charging diode D4 and the capacitor C4 is connected to the anode of the power-off discharge diode D5; the node H2 between the capacitor C4 and the capacitor C5 is connected to the anode of the power-off discharge diode D6; the node H3 between the capacitor C5 and the capacitor C6 is connected to the anode of the power-off discharge diode D7, and the node H4 between the capacitor C6 and the capacitor C7 is connected to the anode of the power-off discharge diode D8.

[0012] A motor controller includes a rectifier circuit, a surge absorption circuit, a filter circuit and a motor inverter circuit. The AC input of the mains is processed by the rectifier circuit to form a DC output terminal A. The DC output terminal A is processed by the surge absorption circuit and the filter circuit to obtain a DC bus voltage Vbus. The DC bus voltage Vbus supplies power to the motor inverter circuit. It is characterized in that the surge absorption circuit is a DC surge absorption circuit as described above.

[0013] The above-mentioned rectifier circuit is a rectifier module BG1, and the filter circuit is a film capacitor C2.

[0014] Compared with the prior art, the utility model has the following effects:

[0015] (1) When a surge voltage is generated instantaneously at the DC output terminal A, the surge voltage is effectively absorbed by the DC surge absorption circuit;

[0016] (2) The DC surge absorption circuit stores voltage energy through capacitors and converts it into motor energy, effectively reducing surge voltage, reducing voltage fluctuations and improving working stability;

[0017] (3) The DC surge absorption circuit can adjust the surge suppression capability parameters, i.e., the capacitance parameters, according to the surge energy, which is highly flexible;

[0018] (4) DC surge absorption circuit: does not affect the power factor of the whole machine; has a good effect on suppressing sudden surge voltage; recovers surge power energy; and provides freewheeling for instantaneous power failure. Description of the drawings:

[0019] Figure 1 It is a DC surge voltage curve diagram in the prior art;

[0020] Figure 2 It is a circuit diagram of a DC surge absorption circuit in the prior art;

[0021] Figure 3 It is another circuit diagram of a DC surge absorption circuit in the prior art;

[0022] Figure 4 It is a suppression curve diagram of a DC surge absorption circuit in the prior art;

[0023] Figure 5 It is a circuit diagram of a straight current surge absorption circuit of an embodiment of the utility model;

[0024] Figure 6 It is a circuit block diagram of the second embodiment of the utility model;

[0025] Figure 7 yes Figure 6 The corresponding circuit diagram;

[0026] Figure 8 This is a circuit diagram of a DC surge absorption circuit according to Embodiment 3 of the present utility model;

[0027] Fig. 9 It is a schematic diagram of surge suppression of a DC surge absorption circuit of the utility model. Specific implementation method:

[0028] The present invention will be further described in detail below through specific embodiments in conjunction with the accompanying drawings.

[0029] Embodiment 1:

[0030] like Figure 5As shown, a DC surge absorption circuit provided in this embodiment is connected between a DC output terminal A and a ground terminal PGND, and is characterized in that: it includes a capacitor C1, a capacitor C3, a varistor VAR1, a varistor VAR2, a discharge resistor R1, a discharge resistor R2, a surge charging diode D2, a power-off discharge diode D1 and a power-off discharge diode D3, the capacitor C1, the surge charging diode D2 and the capacitor C3 are connected in series, and the two ends are respectively connected to the DC output terminal A of the rectifier circuit and the ground terminal PGND, and the two ends of the capacitor C1 are respectively connected to the DC output terminal A and the surge charging diode D2. The positive electrode of the tube D2 and the two ends of the capacitor C3 are respectively connected to the negative electrode of the surge charging diode D2 and the ground terminal PGND, the positive electrode of the power-off discharge diode D1 is connected to the negative electrode of the surge charging diode D2, and the negative electrode of the power-off discharge diode D1 is connected to the DC output terminal A; the positive electrode of the power-off discharge diode D3 is connected to the ground terminal PGND, and the negative electrode of the power-off discharge diode D3 is connected to the positive electrode of the surge charging diode D2, the varistor VAR1 and the discharge resistor R1 are respectively connected in parallel at the two ends of the capacitor C1, and the varistor VAR2 and the discharge resistor R2 are respectively connected in parallel at the two ends of the capacitor C3.

[0031] The working principle of the DC surge absorption circuit of this scheme is as follows: in the normal operation state of the motor, the DC voltage comes from the VDC DC power supply which is obtained by rectifying the AC input of the mains through the rectifier bridge BG1; because the power is taken from the mains power grid, the grid is extremely harsh, caused by various loads, the common ones are capacitive load, resistive load, inductive load, etc., and there is also lightning, and surge voltage exists at all times; when the DC output terminal A instantly generates a surge voltage, the capacitor C1 and the capacitor C3 are charged through the DC surge absorption circuit capacitor C1, the surge charging diode D2, and the capacitor C3, the varistor VAR1 and the varistor VAR2 suppress the voltage to ensure that the voltage will not be overcharged and damage the capacitor, the discharge resistor R1 and the discharge resistor R2 release the surge voltage and balance the voltage of the capacitor C1 and the capacitor C3, play the role of equalization and discharge, when the voltage of the capacitor C1 and the capacitor C3 is too high or the capacitor C2 loses power instantly, it plays a freewheeling role, and the freewheeling current is passed through the power-off discharge diode D1 and the power-off discharge diode D3 to the capacitor C2 in the filter circuit. The voltage energy is provided by capacitor C2 as the main filter capacitor to power the subsequent circuit, and the motor inverter circuit converts the electrical energy and transmits it to the motor to ensure stable operation of the motor.

[0032] Advantages of the utility model:

[0033] 1. When a surge voltage is generated at the DC output terminal A of the DC power supply, the surge voltage is effectively absorbed by the DC surge absorption circuit, see Fig. 9 The absorption curve of

[0034] 2. The DC surge absorption circuit stores voltage energy through capacitors and converts it into motor energy, effectively reducing surge voltage, reducing voltage fluctuations and improving working stability; see Fig. 9 The absorption curve.

[0035] 3. DC surge absorption circuit, when the motor is working normally, the charging voltage of capacitor C1 and capacitor C3 is equal to the capacitor voltage of capacitor C2. Due to the existence of surge charging diode D2, the capacitor cannot be discharged, and it has no effect on other functions of the whole machine. The higher the surge voltage, the greater the charging current of capacitor C1 and capacitor C3, and the higher the suppression voltage energy. The surge suppression capacity parameters can be adjusted according to the surge energy, which is highly flexible;

[0036] 4. DC surge absorption circuit: does not affect the power factor of the whole machine; has good suppression effect on surge voltage; recovers surge power; plays a role in providing freewheeling current for instantaneous power failure;

[0037] Embodiment 2:

[0038] like Figure 6 and Figure 7 As shown, a motor controller includes a rectifier circuit, a surge absorption circuit, a filter circuit and a motor inverter circuit. The AC input of the mains is processed by the rectifier circuit to form a DC output terminal A. The DC output terminal A is processed by the surge absorption circuit and the filter circuit to obtain a DC bus voltage Vbus. The DC bus voltage Vbus supplies power to the motor inverter circuit. It is characterized in that: the surge absorption circuit is a DC surge absorption circuit described in Example 1.

[0039] The above-mentioned rectifier circuit is the rectifier module BG1, and the filter circuit is the film capacitor C2.

[0040] Embodiment three:

[0041] This embodiment is an improvement on the first and second embodiments. Figure 8As shown, a DC surge absorption circuit provided in this embodiment is connected between a DC output terminal A and a ground terminal PGND, and is characterized in that: it includes a capacitor C4, a capacitor C5, a capacitor C6, a capacitor C7, a discharge resistor R3, a discharge resistor R4, a discharge resistor R5, a discharge resistor R6, a surge charging diode D4, a power-off discharge diode D5, a power-off discharge diode D6, a power-off discharge diode D7 and a power-off discharge diode D8, wherein the surge charging diode D4, the capacitor C4, the capacitor C5, the capacitor C6 and the capacitor C7 are connected in series, and the two ends thereof are respectively connected to the DC output terminal A of the rectifier circuit and the ground terminal PGND, the positive electrode of the surge charging diode D4 is connected to the DC output terminal A, and the negative electrode of the surge charging diode D4 is connected to one end of the capacitor C4, The discharge resistor R3 is connected in parallel at both ends of the capacitor C4, the discharge resistor R4 is connected in parallel at both ends of the capacitor C5, the discharge resistor R5 is connected in parallel at both ends of the capacitor C6, the discharge resistor R6 is connected in parallel at both ends of the capacitor C7, the negative electrodes of the power-off discharge diode D5, the power-off discharge diode D6, the power-off discharge diode D7 and the power-off discharge diode D8 are all connected to the DC output terminal A, the node H1 between the surge charging diode D4 and the capacitor C4 is connected to the positive electrode of the power-off discharge diode D5; the node H2 between the capacitor C4 and the capacitor C5 is connected to the positive electrode of the power-off discharge diode D6; the node H3 between the capacitor C5 and the capacitor C6 is connected to the positive electrode of the power-off discharge diode D7, and the node H4 between the capacitor C6 and the capacitor C7 is connected to the positive electrode of the power-off discharge diode D8.

[0042] It is obtained after the mains passes through the rectifier circuit (rectifier bridge BG1); since the power is taken from the mains power grid, the grid is extremely bad, and various loads are caused, including capacitive load, resistive load, inductive load, etc., and there is lightning, and surge voltage exists at all times; when the DC output terminal A of the rectifier circuit instantly generates a surge voltage, it is charged through the surge charging diode D4, capacitor C4, capacitor C5, capacitor C6 and capacitor C7 of the surge absorption circuit, and the discharge resistor R3, discharge resistor R4, discharge resistor R5, discharge resistor R6 and other resistors release the surge voltage and balance the capacitor voltage of capacitor C4, capacitor C5, capacitor C6 and capacitor C7, play a role of voltage balancing and discharge, when the voltage of capacitor C4, capacitor C5, capacitor C6 and capacitor C7 is too high or the capacitor C2 is instantly powered off, it plays a freewheeling role, and the freewheeling current is passed through the power-off discharge diode D5, power-off discharge diode D6, power-off discharge diode D7 and power-off discharge diode D8 to the capacitor C2 in the filter circuit. The voltage energy is provided by capacitor C2 as the main filter capacitor to power the subsequent circuit, and the motor inverter circuit converts the electrical energy and transmits it to the motor to ensure stable operation of the motor.

[0043] Advantages of the utility model:

[0044] 1. When a surge voltage is generated at the DC output terminal A of the DC power supply, the surge voltage is effectively absorbed by the DC surge absorption circuit, see Fig. 9 The absorption curve of

[0045] 2. The DC surge absorption circuit stores voltage energy through capacitors and converts it into motor energy, effectively reducing surge voltage, reducing voltage fluctuations and improving working stability; see Fig. 9 The absorption curve.

[0046] 3. DC surge absorption circuit, when the motor is working normally, the capacitors C4, C5, C6 and C7 are charged to the same voltage as the capacitor C2. Due to the existence of surge charging diode D4, the capacitor cannot be discharged, and it has no effect on other functions of the whole machine. The higher the surge voltage, the greater the charging current of capacitors C4, C5, C6 and C7, and the higher the suppression voltage energy. The surge suppression capacity parameters can be adjusted according to the surge energy, which is highly flexible;

[0047] 4. DC surge absorption circuit: does not affect the power factor of the whole machine; has good suppression effect on surge voltage; recovers surge power; plays a role in providing freewheeling current for instantaneous power failure;

[0048] Embodiment 4:

[0049] A motor controller includes a rectifier circuit, a surge absorption circuit, a filter circuit and a motor inverter circuit. The AC input of the mains is processed by the rectifier circuit to form a DC output terminal A. The DC output terminal A is processed by the surge absorption circuit and the filter circuit to obtain a DC bus voltage Vbus. The DC bus voltage Vbus supplies power to the motor inverter circuit. It is characterized in that: the surge absorption circuit is a DC surge absorption circuit described in Example 3.

[0050] The above-mentioned rectifier circuit is the rectifier module BG1, and the filter circuit is the film capacitor C2.

[0051] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited thereto. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention are equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A DC surge absorption circuit, connected between a DC output terminal A and a ground terminal PGND, characterized in that: It includes a capacitor C1, a capacitor C3, a varistor VAR1, a varistor VAR2, a discharge resistor R1, a discharge resistor R2, a surge charging diode D2, a power-off discharge diode D1 and a power-off discharge diode D3. After the capacitor C1, the surge charging diode D2 and the capacitor C3 are connected in series, the two ends are respectively connected to the DC output terminal A of the rectifier circuit and the ground terminal PGND, the two ends of the capacitor C1 are respectively connected to the DC output terminal A and the positive electrode of the surge charging diode D2, the two ends of the capacitor C3 are respectively connected to the negative electrode of the surge charging diode D2 and the ground terminal PGND, the positive electrode of the power-off discharge diode D1 is connected to the negative electrode of the surge charging diode D2, and the negative electrode of the power-off discharge diode D1 is connected to the DC output terminal A; the positive electrode of the power-off discharge diode D3 is connected to the ground terminal PGND, and the negative electrode of the power-off discharge diode D3 is connected to the positive electrode of the surge charging diode D2, the varistor VAR1 and the discharge resistor R1 are respectively connected in parallel to the two ends of the capacitor C1, and the varistor VAR2 and the discharge resistor R2 are respectively connected in parallel to the two ends of the capacitor C3.

2. A motor controller, comprising a rectifier circuit, a surge absorption circuit, a filter circuit and a motor inverter circuit, wherein the AC input of the mains is processed by the rectifier circuit to form a DC output terminal A, and the DC output terminal A is processed by the surge absorption circuit and the filter circuit to obtain a DC bus voltage Vbus, and the DC bus voltage Vbus is used to power the motor inverter circuit; characterized in that: The surge absorption circuit is a DC surge absorption circuit as claimed in claim 1.

3. A motor controller according to claim 2, characterized in that: The rectifier circuit is the rectifier module BG1, and the filter circuit is the film capacitor C2.

4. A DC surge absorption circuit, connected between a DC output terminal A and a ground terminal PGND, characterized in that: It includes capacitor C4, capacitor C5, capacitor C6, capacitor C7, discharge resistor R3, discharge resistor R4, discharge resistor R5, discharge resistor R6, surge charging diode D4, power-off discharge diode D5, power-off discharge diode D6, power-off discharge diode D7 and power-off discharge diode D8. The surge charging diode D4, capacitor C4, capacitor C5, capacitor C6 and capacitor C7 are connected in series, and their two ends are respectively connected to the DC output terminal A of the rectifier circuit and the ground terminal PGND. The positive electrode of the surge charging diode D4 is connected to the DC output terminal A, and the negative electrode of the surge charging diode D4 is connected to one end of the capacitor C4. The discharge resistor R3 is connected in parallel to the two ends of the capacitor C4. The discharge resistor R4 is connected in parallel to the two ends of the capacitor C4. The discharge resistor R5 is connected in parallel at both ends of the capacitor C5, the discharge resistor R6 is connected in parallel at both ends of the capacitor C7, the negative electrodes of the power-off discharge diode D5, the power-off discharge diode D6, the power-off discharge diode D7 and the power-off discharge diode D8 are all connected to the DC output terminal A, the node H1 between the surge charging diode D4 and the capacitor C4 is connected to the positive electrode of the power-off discharge diode D5; the node H2 between the capacitor C4 and the capacitor C5 is connected to the positive electrode of the power-off discharge diode D6; the node H3 between the capacitor C5 and the capacitor C6 is connected to the positive electrode of the power-off discharge diode D7, and the node H4 between the capacitor C6 and the capacitor C7 is connected to the positive electrode of the power-off discharge diode D8.

5. A motor controller, comprising a rectifier circuit, a surge absorption circuit, a filter circuit and a motor inverter circuit, wherein the AC input of the mains is processed by the rectifier circuit to form a DC output terminal A, and the DC output terminal A is processed by the surge absorption circuit and the filter circuit to obtain a DC bus voltage Vbus, and the DC bus voltage Vbus is used to power the motor inverter circuit; characterized in that: The surge absorption circuit is a DC surge absorption circuit as described in claim 4.

6. A motor controller according to claim 5, characterized in that: The rectifier circuit is the rectifier module BG1, and the filter circuit is the film capacitor C2.

Images