Voltage sampling circuit and servo driver

Abstract

This invention discloses a voltage sampling circuit and a servo driver. The voltage sampling circuit includes an electrical signal processing module, a transformer module, a sampling module, and a switching module. One end of the switching module is electrically connected to one end of the electrical signal processing module. The transformer module includes a primary winding and a first secondary winding. One end of the primary winding is electrically connected to the other end of the electrical signal processing module, and the other end of the primary winding is electrically connected to the other end of the switching module. The first secondary winding is used to generate a first secondary signal. One end of an inverter circuit is electrically connected to one end of the primary winding, and the other end of the inverter circuit is electrically connected to one end of the switching module. The sampling module is electrically connected to the first secondary winding and generates a sampling signal based on the first secondary signal. This voltage sampling circuit enables the acquisition of the output voltage of the electrical signal processing module even when the transformer only includes one set of output windings.

Description

Technical Field

[0001] This invention relates to the field of servo drive control, and in particular to a voltage sampling circuit and a servo driver. Background Technology

[0002] Currently, devices using servo motors typically utilize servo drivers to control them. The electrical signal processing module in the servo driver rectifies and filters the AC power supply, and the processed voltage is converted into a sinusoidal current by an inverter circuit to control the servo motor's rotation. When the servo motor has a large load inertia and experiences significant deceleration, it will reverse-charge the bus capacitor in the electrical signal processing module through the freewheeling diode in the inverter circuit. This causes the bus capacitor voltage to rise. Since the bus capacitor has a limited withstand voltage, if the voltage exceeds this limit, the servo driver and servo motor will not operate safely and stably.

[0003] In related technologies, the voltage at the output of the electrical signal processing module can be acquired through the auxiliary switching power supply of the servo driver. However, the transformer in the auxiliary switching power supply requires multiple output windings to acquire the voltage at the output of the electrical signal processing module, which increases the design difficulty of the transformer and its actual size, thereby increasing the space occupied by the corresponding PCB. Summary of the Invention

[0004] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a voltage sampling circuit that can acquire the output voltage of the electrical signal processing module when the transformer only includes one set of output windings, thereby reducing the design difficulty of the transformer and reducing the actual size of the transformer, thus saving the space occupied by the transformer on the PCB.

[0005] The present invention also proposes a servo driver having the above-described voltage sampling circuit.

[0006] A voltage sampling circuit according to a first aspect embodiment of the present invention is applied to a servo driver, the servo driver comprising:

[0007] An inverter circuit, wherein the inverter circuit is electrically connected to the voltage sampling circuit;

[0008] An electrical signal processing module is provided, which is electrically connected to a power supply and is used to rectify and filter the power supply signal of the power supply.

[0009] A switching module, one end of which is electrically connected to one end of the electrical signal processing module;

[0010] The voltage sampling circuit includes:

[0011] A transformer module includes a primary winding and a first secondary winding. One end of the primary winding is electrically connected to the other end of the electrical signal processing module, and the other end of the primary winding is electrically connected to the other end of the switching module. The first secondary winding is used to generate a first secondary signal based on the rectified and filtered power supply signal. One end of the inverter circuit is electrically connected to one end of the primary winding, and the other end of the inverter circuit is electrically connected to one end of the switching module.

[0012] The sampling module is electrically connected to the first secondary winding, and is used to switch the sampling state according to the conduction state of the switching module. The sampling module is also used to generate a sampling signal based on the first secondary signal.

[0013] The voltage sampling circuit according to an embodiment of the present invention has at least the following beneficial effects: After the switching module is turned on, the electrical signal processing module is connected in parallel with the primary winding and the inverter circuit, respectively. That is, at this time, the voltage at the output terminal of the electrical signal processing module is equal to the voltage at both ends of the primary winding and the voltage at the input terminal of the inverter circuit. The transformer converts the voltage at both ends of the primary winding into the voltage at both ends of the first secondary winding, and the first secondary winding generates a first secondary signal. The sampling module receives and stores the first secondary signal. After the switching module is turned off, the sampling module generates a sampling signal based on the first secondary signal. Finally, the sampling signal is calculated and processed to obtain the voltage at the output terminal of the electrical signal processing module. This embodiment can achieve the acquisition of the voltage at the output terminal of the electrical signal processing module when the transformer only includes one set of output windings, thereby reducing the design difficulty of the transformer and reducing the actual size of the transformer, thus saving the space occupied by the transformer on the PCB.

[0014] According to some embodiments of the present invention, the sampling module includes:

[0015] A first capacitor, one end of which is used to be electrically connected to one end of the first secondary winding;

[0016] A first diode, the cathode of which is electrically connected to the other end of the first capacitor;

[0017] A first resistor, one end of which is electrically connected to the anode of the first diode, and the other end of which is electrically connected to the other end of the first secondary winding;

[0018] The second resistor, one end of which is used to be electrically connected to the other end of the first capacitor and the cathode of the first diode, respectively;

[0019] A third resistor, one end of which is electrically connected to the other end of the second resistor, and the other end of which is grounded.

[0020] According to some embodiments of the present invention, the sampling module includes:

[0021] A fourth resistor, one end of which is electrically connected to one end of the first secondary winding;

[0022] The second diode, the anode of which is used to be electrically connected to the other end of the fourth resistor;

[0023] The second capacitor has one end for electrical connection to the cathode of the second diode, and the other end is grounded.

[0024] The fifth resistor, one end of which is used to be electrically connected to the cathode of the second diode and one end of the second capacitor, respectively;

[0025] A sixth resistor, one end of which is electrically connected to the other end of the fifth resistor, and the other end of the sixth resistor is grounded.

[0026] According to some embodiments of the present invention, the transformer module further includes:

[0027] The third capacitor has one end for electrical connection to one end of the first secondary winding, and the other end of the third capacitor is grounded.

[0028] The third diode, the cathode of which is electrically connected to the other end of the first secondary winding, is grounded.

[0029] According to some embodiments of the present invention, the transformer module includes:

[0030] The second secondary winding, one end of which is used to be electrically connected to the other end of the first secondary winding;

[0031] According to some embodiments of the present invention, the transformer module further includes:

[0032] The first energy storage unit is used to be electrically connected to the first secondary winding, one end of the fourth resistor and the power supply ground, respectively.

[0033] The second energy storage unit is used to connect to the second secondary winding, the other end of the second capacitor, and the power supply ground, respectively.

[0034] According to some embodiments of the present invention, the first energy storage unit includes:

[0035] A fourth capacitor, one end of which is used to be electrically connected to one end of the first secondary winding;

[0036] The fourth diode has its cathode electrically connected to the other end of the fourth capacitor, and its anode electrically connected to the other end of the first secondary winding and the power supply ground, respectively.

[0037] The second energy storage unit includes:

[0038] The fifth capacitor, one end of which is used to be electrically connected to one end of the second secondary winding, the other end of the second capacitor, and the power supply ground, respectively;

[0039] The fifth diode has its cathode electrically connected to the other end of the fifth capacitor, and its anode electrically connected to the other end of the second secondary winding.

[0040] According to some embodiments of the present invention, the electrical signal processing module includes:

[0041] A rectifier unit is provided, which is electrically connected to the power supply and is used to rectify the power supply.

[0042] The sixth capacitor is used to be electrically connected to the rectifier unit. One end of the sixth capacitor is used to be electrically connected to one end of the primary winding and one end of the inverter circuit, respectively. The other end of the sixth capacitor is used to be electrically connected to one end of the switching module and the other end of the inverter circuit, respectively. The sixth capacitor is used to filter the rectified power supply.

[0043] According to some embodiments of the present invention, the switching module includes:

[0044] A voltage-controlled current element, wherein the drain of the voltage-controlled current element is electrically connected to the other end of the primary winding, the source of the voltage-controlled current element is electrically connected to the other end of the sixth capacitor, the gate of the voltage-controlled current element is used to receive a switching signal, and the voltage-controlled current element is used to turn on or off according to the switching signal.

[0045] According to a second aspect of the present invention, a servo driver is applied to a servo motor, the servo driver comprising:

[0046] The voltage sampling circuit according to the first aspect embodiment of the present invention;

[0047] An inverter circuit is provided, which is used to electrically connect to the electrical signal processing module and the servo motor respectively.

[0048] The servo driver according to the embodiments of the present invention has at least the following beneficial effects: by employing the voltage sampling circuit described above, the servo driver can acquire the voltage at the output terminal of the electrical signal processing module when the transformer only includes one set of output windings, thereby reducing the design difficulty of the transformer and reducing the actual size of the transformer, thus saving the space occupied by the transformer on the PCB.

[0049] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0050] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0051] Figure 1 This is a module block diagram of a specific embodiment of the voltage sampling circuit of the present invention;

[0052] Figure 2 This is a circuit schematic diagram of a specific embodiment of the voltage sampling circuit of the present invention;

[0053] Figure 3 This is a circuit diagram of another specific embodiment of the voltage sampling circuit of the present invention.

[0054] Figure label:

[0055] Electrical signal processing module 100, transformer module 200, sampling module 300, switching module 400, inverter circuit 500, rectifier unit 110, primary winding 210, first secondary winding 220, second secondary winding 230, first energy storage unit 240, and second energy storage unit 250. Detailed Implementation

[0056] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0057] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0058] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0059] In the description of this invention, unless otherwise explicitly defined, terms such as setting, installing, connecting, and electrical connection should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0060] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0061] like Figure 1 As shown, this embodiment of the invention provides a voltage sampling circuit applied to a servo driver. The servo driver includes an inverter circuit 500, an electrical signal processing module 100, and a switching module 400. The inverter circuit 500 is electrically connected to the voltage sampling circuit; the electrical signal processing module 100 is electrically connected to a power supply and performs rectification and filtering processing on the power signal provided by the power supply; one end of the switching module 400 is electrically connected to one end of the electrical signal processing module 100. The voltage sampling circuit includes a transformer module 200 and a sampling module 300. The transformer module 200 includes a primary winding 210 and a first secondary winding 220. One end of the primary winding 210 is electrically connected to the other end of the electrical signal processing module 100, and the other end of the primary winding 210 is electrically connected to the other end of the switching module 400. The first secondary winding 220 is used to generate a first secondary signal based on the rectified and filtered power supply signal. One end of the inverter circuit 500 is electrically connected to one end of the primary winding 210, and the other end of the inverter circuit 500 is electrically connected to one end of the switching module 400. The sampling module 300 is used to be electrically connected to the first secondary winding 220, and the sampling module 300 is used to switch the sampling state according to the conduction state of the switching module 400. The sampling module 300 is used to generate a sampling signal based on the first secondary signal.

[0062] Specifically, after rectifying and filtering the power supply, the electrical signal processing module 100 outputs the processed voltage to the inverter circuit 500. In this embodiment, the output terminal of the electrical signal processing module 100 is electrically connected to one end of the primary winding 210 of the transformer module 200 and one end of the switch module 400, respectively. The other end of the primary winding 210 is electrically connected to the other end of the switch module 400, so that when the switch module 400 is turned on, the primary winding 210 is connected in parallel with the output terminal of the electrical signal processing module 100 and the inverter circuit 500, respectively. That is, at this time, the voltage across the primary winding 210 is equal to the voltage across the output terminal of the electrical signal processing module 100.

[0063] After the switching module 400 is turned on, the transformer converts the voltage across the primary winding 210 into the voltage across the first secondary winding 220, i.e., the first secondary winding 220 generates a first secondary signal. The sampling module receives and stores the first secondary signal. Since the voltage across the primary winding 210 is equal to the voltage across the output terminal of the electrical signal processing module 100 at this time, the first secondary signal contains the electrical signal information of the output voltage of the electrical signal processing module 100. After the switching module 400 is turned off, the sampling module 300 generates a sampling signal based on the aforementioned first secondary signal, and finally performs calculations and processing on the sampling signal to obtain the voltage at the output terminal of the electrical signal processing module 100.

[0064] According to the voltage sampling circuit of the present invention, the voltage at the output terminal of the electrical signal processing module 100 can be acquired when the transformer uses only a single output winding, thereby reducing the design difficulty of the transformer and reducing the actual size of the transformer, thus saving the space occupied by the transformer on the PCB.

[0065] like Figure 2 As shown, in a specific embodiment of the present invention, the transformer module 200 further includes a third capacitor C3 and a third diode D3. One end of the third capacitor C3 is electrically connected to one end of the first secondary winding 220, and the other end of the third capacitor C3 is grounded. The cathode of the third diode D3 is electrically connected to the other end of the first secondary winding 220, and the cathode of the third diode D3 is grounded.

[0066] Specifically, the third capacitor C3 and the third diode D3 form an energy storage unit, and the transformer module 200 and the switch module 400 form an auxiliary switching power supply. The voltage sampling circuit in this embodiment is applied to the case where the downstream load of the auxiliary switching power supply needs positive power supply, that is, the energy storage unit composed of the third capacitor C3 and the third diode D3 can provide positive power supply for the downstream load.

[0067] When the switching module 400 is turned on, the primary winding 210 is connected in parallel with both the output of the electrical signal processing module 100 and the inverter circuit 500. The primary winding 210 acts as a load, with its upper voltage being positive and its lower voltage being negative. Therefore, the lower voltage of the first secondary winding 220 is positive and its upper voltage is negative. At this time, the third diode D3 is reverse-biased and cut off, and the first secondary winding 220 does not affect the third capacitor C3. The third capacitor C3 provides positive power to the downstream load. After the switching module 400 is turned off, the upper voltage of the primary winding 210 is negative and its lower voltage is positive, and correspondingly, the upper voltage of the first secondary winding 220 is positive and its lower voltage is negative. The third diode D3 is forward-biased, and the third capacitor C3 begins to charge, maintaining the voltage across the third capacitor C3 at Vc3.

[0068] like Figure 2 As shown, in a specific embodiment of the present invention, the sampling module 300 includes: a first capacitor C1, a first diode D1, a first resistor R1, a second resistor R2, and a third resistor R3. One end of the first capacitor C1 is electrically connected to one end of the first secondary winding 220, the cathode of the first diode D1 is electrically connected to the other end of the first capacitor C1, one end of the first resistor R1 is electrically connected to the anode of the first diode D1, the other end of the first resistor R1 is electrically connected to the other end of the first secondary winding 220, one end of the second resistor R2 is electrically connected to the other end of the first capacitor C1 and the cathode of the first diode D1, respectively, one end of the third resistor R3 is electrically connected to the other end of the second resistor R2, and the other end of the third resistor R3 is grounded.

[0069] Specifically, the transformer module 200 and the switch module 400 form an auxiliary switching power supply. In this embodiment, the voltage sampling circuit is used when the downstream load of the auxiliary switching power supply requires positive power. That is, the third capacitor C3 and the third diode D3 in the auxiliary switching power supply of this embodiment can provide positive power to the downstream load. A sampling signal output port VSAMPLE is provided at the connection node of the second resistor R2 and the third resistor R3.

[0070] When the switching module 400 is turned on, the primary winding 210 is essentially connected in parallel with both the output of the electrical signal processing module 100 and the inverter circuit 500. The primary winding 210 acts as a load, with a positive voltage at its upper end and a negative voltage at its lower end. Both the voltage across the primary winding 210 and the voltage across the output of the electrical signal processing module 100 are Vdc. The transformer converts this voltage Vdc across the primary winding 210 into the voltage across the first secondary winding 220. Let the number of turns in the primary winding 210 be N. P The first secondary winding has 220 turns and N. S1 Therefore, the first secondary signal generated by the first secondary winding 220 is Vdc*N. S1 / N P Meanwhile, since the voltage at the upper end of the primary winding 210 is positive and the voltage at the lower end is negative, the voltage at the lower end of the first secondary winding 220 is positive and the voltage at the upper end is negative. The first secondary winding 220 will charge the first capacitor C1 through the first resistor R1 and the first diode D1. After the first capacitor C1 is fully charged, the voltage Vcd1 across the first capacitor C1 and the first diode D1 connected in series satisfies: Vcd1 = Vdc * N S1 / N P That is, the first capacitor C1 stores the first secondary signal. At this time, the third diode D3 is reverse cut off, the first secondary winding 220 does not affect the third capacitor C3, and the third capacitor C3 provides positive power supply to the downstream load.

[0071] After the switch module 400 is turned off, the upper voltage of the primary winding 210 is negative and the lower voltage is positive. Correspondingly, the upper voltage of the first secondary winding 220 is positive and the lower voltage is negative. The third diode D3 is forward-biased, and the third capacitor C3 begins to charge, maintaining a voltage of Vc3 across C3. Since the first diode D1 is reverse-biased when the upper voltage of the first secondary winding 220 is positive and the lower voltage is negative, the first capacitor C1 discharges through the second resistor R2 and the third resistor R3. Assuming the forward voltage drop of the first diode D1 is Vd1, the voltage across the third capacitor C3 is Vc3, and the resistances of the second resistor R2 and the third resistor R3 are R3, then the voltage Vsample at the sampling signal output terminal VSAMPLE satisfies:

[0072] Vsample=(Vdc*N S1 / N P -Vd1+Vc3)*R3 / (R2+R3) (1)

[0073] After the output voltage Vsample is sampled by the ADC, the voltage Vdc at both ends of the output terminal of the electrical signal processing module 100 can be obtained by the above formula (1).

[0074] Since the switching frequency of the switching module 400 is generally tens of kHz, and the duty cycle of each cycle is generally less than or equal to 50%, in order to ensure that the voltage across the first capacitor C1 can fully reflect the voltage across the output terminal of the electrical signal processing module 100, the voltage across the first capacitor C1 must not drop rapidly during the off period of the switching module 400. Let the switching cycle of the switching module 400 be Ts, then the capacitance C1 of the first capacitor C1, the resistance R2 of the second resistor R2, and the resistance R3 of the third resistor R3 should satisfy: (R2+R3)*C1>>0.5Ts. Simultaneously, the charging time constant must be less than the discharging time constant. Let the resistance R1 of the first resistor R1 be R1, then the capacitance C1 of the first capacitor C1, the resistance R1 of the first resistor R1, the resistance R2 of the second resistor R2, and the resistance R3 of the third resistor R3 should satisfy: (R2+R3)*C1>10*R1*C1.

[0075] During the acceleration process of the servo motor, the voltage across the output terminals of the electrical signal processing module 100 drops rapidly, and the acceleration time is generally about tens of milliseconds (ms). During the off period of the switching module 400, since the voltage across the third capacitor C3 remains constant at Vc3, in order to ensure that the voltage across the first capacitor C1 can respond promptly to the fluctuations in the voltage across the output terminals of the electrical signal processing module 100, the capacitance value C1 of the first capacitor C1, the resistance value R2 of the second resistor R2, and the resistance value R3 of the third resistor R3 should satisfy: (R2+R3)*C1<20ms.

[0076] like Figure 3 As shown, in a specific embodiment of the present invention, the transformer module 200 includes: a second secondary winding 230, a first energy storage unit 240 and a second energy storage unit 250. One end of the second secondary winding 230 is used to be electrically connected to the other end of the first secondary winding 220. The first energy storage unit 240 is used to be electrically connected to the first secondary winding 220, one end of the fourth resistor R4 and the power supply ground, respectively. The first energy storage unit 240 includes a fourth capacitor C4 and a fourth diode D4. One end of the fourth capacitor C4 is electrically connected to one end of the first secondary winding 220. The cathode of the fourth diode D4 is electrically connected to the other end of the fourth capacitor C4. The anode of the fourth diode D4 is electrically connected to the other end of the first secondary winding 220 and the power supply ground, respectively. The second energy storage unit 250 includes a fifth capacitor C5 and a fifth diode D5. One end of the fifth capacitor C5 is electrically connected to one end of the second secondary winding 230, the other end of the second capacitor C2, and the power supply ground, respectively. The cathode of the fifth diode D5 is electrically connected to the other end of the fifth capacitor C5. The anode of the fifth diode D5 is electrically connected to the other end of the second secondary winding 230.

[0077] Specifically, the transformer module 200 and the switch module 400 form an auxiliary switching power supply. The voltage sampling circuit in this embodiment is applied to the situation where the downstream load of the auxiliary switching power supply needs both positive and negative power supply at the same time. That is, the first energy storage unit 240 in the auxiliary switching power supply of this embodiment can provide negative power supply to the downstream load, and the second energy storage unit 250 can provide positive power supply to the downstream load.

[0078] When the switching module 400 is turned on, the primary winding 210 is equivalent to being connected in parallel with the output terminal of the electrical signal processing module 100 and the inverter circuit 500 respectively. The primary winding 210 acts as a load, with its upper voltage being positive and its lower voltage being negative. Therefore, the lower voltage of the first secondary winding 220 and the second secondary winding 230 are both high and the upper voltage is low, causing the fourth diode D4 and the fifth diode D5 to be forward-biased. At this time, the first secondary winding 220 charges the fourth capacitor C4, and the second secondary winding 230 charges the fifth capacitor C5. After the switch module 400 is turned off, the upper voltage of the primary winding 210 is negative and the lower voltage is positive. The upper voltage of both the first secondary winding 220 and the second secondary winding 230 is high and the lower voltage is low, causing the fourth diode D4 and the fifth diode D5 to be reverse-biased and cut off. At this time, the first secondary winding 220 does not affect the fourth capacitor C4, and the second secondary winding 230 does not affect the fifth capacitor C5. Simultaneously, since the connection point between the first secondary winding 220 and the second secondary winding 230 is grounded, the fourth capacitor C4 provides a negative power supply to the downstream load, and the fifth capacitor C5 provides a positive power supply to the downstream load.

[0079] like Figure 3 As shown, in some specific embodiments of the present invention, the sampling module 300 includes: a fourth resistor R4, a second diode D2, a second capacitor C2, a fifth resistor R5, and a sixth resistor R6. One end of the fourth resistor R4 is electrically connected to one end of the first secondary winding 220; the anode of the second diode D2 is electrically connected to the other end of the fourth resistor R4; one end of the second capacitor C2 is electrically connected to the cathode of the second diode D2, and the other end of the second capacitor C2 is grounded; one end of the fifth resistor R5 is electrically connected to the cathode of the second diode D2 and one end of the second capacitor C2, respectively; one end of the sixth resistor R6 is electrically connected to the other end of the fifth resistor R5, and the other end of the sixth resistor R6 is grounded.

[0080] Specifically, the transformer module 200 and the switch module 400 form an auxiliary switching power supply. The voltage sampling circuit in this embodiment is used when the downstream load of the auxiliary switching power supply requires both positive and negative power supplies. That is, the first energy storage unit 240 in the auxiliary switching power supply of this embodiment can provide negative power to the downstream load, and the second energy storage unit 250 can provide positive power to the downstream load. A sampling signal output port VSAMPLE is provided at the connection node of the fifth resistor R5 and the sixth resistor R6.

[0081] When the switching module 400 is turned on, the primary winding 210 is essentially connected in parallel with both the output of the electrical signal processing module 100 and the inverter circuit 500. The primary winding 210 acts as a load, with its upper voltage being positive and its lower voltage being negative. Both the voltage across the primary winding 210 and the voltage across the output of the electrical signal processing module 100 are Vdc. The transformer converts this voltage Vdc across the primary winding 210 into the voltages across the first secondary winding 220 and the second secondary winding 230. Since the connection point between the first and second secondary windings 220 and 230 is grounded, the voltage at this connection point is 0. The upper voltage of the first secondary winding 220 is negative, and the lower voltage of the second secondary winding 230 is positive. Let the number of turns in the primary winding 210 be N. P The first secondary winding has 220 turns and N. S1 The number of turns in the second secondary winding 230 is N. S2 Therefore, the first secondary signal generated by the first secondary winding 220 is Vdc*N. S1 / N P Meanwhile, since the voltage at the upper end of the first secondary winding 220 is negative and the voltage at the connection point of the first secondary winding 220 and the second secondary winding 230 is 0, the first secondary winding 220 will charge the second capacitor C2 through the fourth resistor R4 and the second diode D2. After the second capacitor C2 is fully charged, the voltage Vcd2 across the second capacitor C2 and the second diode D2 connected in series satisfies: Vcd2=Vdc*N S1 / N P That is, the second capacitor C2 stores the first secondary side signal.

[0082] After the switch module 400 is turned off, the upper voltage of the primary winding 210 is negative and the lower voltage is positive. Therefore, the upper voltage of the first secondary winding 220 is positive, and the voltage at the connection point between the first secondary winding 220 and the second secondary winding 230 is 0. At this time, the second capacitor C2 discharges through the fifth resistor R5 and the sixth resistor R6. Assuming the forward voltage drop of the second diode D2 is Vd2, and the resistances of the fifth resistor R5 and the sixth resistor R6 are R6, the voltage Vsample at the sampling signal output terminal VSAMPLE satisfies:

[0083] Vsample=(Vdc*N S1 / N P -Vd2)*R6 / (R5+R6) (2)

[0084] After the output voltage Vsample is sampled by the ADC, the voltage Vdc at both ends of the output terminal of the electrical signal processing module 100 can be obtained by the above formula (2).

[0085] The specific values ​​of the second capacitor C2, the fourth resistor R4, the fifth resistor R5, and the sixth resistor R6 can be found in the detailed description of the values ​​of the first capacitor C1, the first resistor R1, the second resistor R2, and the third resistor R3 in the aforementioned embodiment.

[0086] like Figure 2 and Figure 3 As shown, in some specific embodiments of the present invention, the electrical signal processing module 100 includes: a rectifier unit 110 and a sixth capacitor C6. The rectifier unit 110 is electrically connected to the power supply and is used to rectify the power supply. The sixth capacitor C6 is electrically connected to the rectifier unit 110. One end of the sixth capacitor C6 is electrically connected to one end of the primary winding 210 and one end of the inverter circuit 500, respectively. The other end of the sixth capacitor C6 is electrically connected to one end of the switching module 400 and the other end of the inverter circuit 500, respectively. The sixth capacitor C6 is used to filter the rectified power supply.

[0087] Specifically, the rectifier unit 110 includes a sixth diode D6, a seventh diode D7, an eighth diode D8, and a ninth diode D9. The anode of the sixth diode D6 is electrically connected to the cathode of the seventh diode D7, the cathode of the sixth diode D6 is electrically connected to the cathode of the eighth diode D8, the anode of the eighth diode D8 is electrically connected to the cathode of the ninth diode D9, and the anode of the ninth diode D9 is electrically connected to the anode of the seventh diode D7. One end of the power supply is electrically connected to the connection node of the sixth and seventh diodes D6, and the other end of the power supply is electrically connected to the connection node of the eighth and ninth diodes D8. The power supply is an AC power supply, which is rectified by the four diodes of the rectifier unit 110 and output to the terminals of the sixth capacitor C6, where it is filtered.

[0088] The two ends of the sixth capacitor C6 also serve as the output terminals of the electrical signal processing module 100. When the switching module 400 is turned on, the sixth capacitor C6 is equivalent to being connected in parallel with the primary winding 210 and the inverter circuit 500 respectively. That is, at this time, the voltage across the sixth capacitor C6 is equal to the voltage across the primary winding 210.

[0089] like Figure 2 and Figure 3 As shown, in some specific embodiments of the present invention, the switching module 400 includes a voltage-controlled current element Q1. The drain of the voltage-controlled current element Q1 is electrically connected to the other end of the primary winding 210, the source of the voltage-controlled current element Q1 is electrically connected to the other end of the sixth capacitor C6, the gate of the voltage-controlled current element Q1 is used to receive a switching signal, and the voltage-controlled current element Q1 is used to turn on or off according to the switching signal.

[0090] Specifically, when the gate of the voltage-controlled current element Q1 receives a low-level switching signal, the voltage-controlled current element Q1 is turned on. At this time, the primary winding 210 is equivalent to being connected in parallel with the sixth capacitor C6 and the inverter circuit 500, respectively. That is, the voltage across the primary winding 210 is equal to the voltage across the sixth capacitor C6. When the gate of the voltage-controlled current element Q1 receives a high-level switching signal, the voltage-controlled current element Q1 is turned off. At this time, the output terminal of the electrical signal processing module 100, that is, the two ends of the sixth capacitor C6, cannot supply power to the primary winding 210.

[0091] The voltage-controlled current element Q1 can be selected as a field-effect PMOS transistor. When the gate of the PMOS transistor receives a low-level switching signal, the PMOS transistor turns on, thereby connecting the power supply path from the sixth capacitor C6 to the primary winding 210, and simultaneously making the voltage across the primary winding 210 equal to the voltage across the sixth capacitor C6. When the gate of the PMOS transistor receives a high-level switching signal, the PMOS transistor turns off, and the power supply from the sixth capacitor C6 to the primary winding 210 is cut off. It is understandable that the specific type of voltage-controlled current element Q1 can be selected adaptively according to actual needs.

[0092] This invention also provides a servo driver, which includes: an inverter circuit and a voltage sampling circuit as described in the above embodiments, wherein the inverter circuit is used to be electrically connected to the electrical signal processing module and the servo motor respectively.

[0093] According to the servo driver of the present invention, by employing the voltage sampling circuit described above, it is possible to acquire the voltage at the output terminal of the electrical signal processing module when the transformer uses only a single output winding, thereby reducing the design difficulty of the transformer and reducing the actual size of the transformer, thus saving the space occupied by the transformer on the PCB.

[0094] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A voltage sampling circuit, characterized by, The application is applied to a servo driver, and the servo driver comprises: an inverter circuit electrically connected with the voltage sampling circuit; an electric signal processing module electrically connected with a power supply, and configured to rectify and filter a power signal provided by the power supply; a switch module having one end electrically connected with one end of the electric signal processing module; the voltage sampling circuit comprises: a transformer module comprising a primary winding, a first secondary winding, one end of the primary winding being electrically connected with the other end of the electric signal processing module, the other end of the primary winding being electrically connected with the other end of the switch module, and the first secondary winding being configured to generate a first secondary signal according to the rectified and filtered power signal; wherein one end of the inverter circuit is electrically connected with one end of the primary winding, and the other end of the inverter circuit is electrically connected with one end of the switch module; the transformer module further comprises a third capacitor and a third diode, one end of the third capacitor being electrically connected with one end of the first secondary winding, and the other end of the third capacitor being grounded, and the cathode of the third diode being electrically connected with the other end of the first secondary winding and grounded; the third capacitor and the third diode are configured to form an energy storage unit to provide a positive power supply; a sampling module electrically connected with the first secondary winding, configured to switch a sampling state according to the conduction state of the switch module, and further configured to generate a sampling signal according to the first secondary signal; the sampling module comprises a first capacitor, a first diode, a first resistor, a second resistor and a third resistor, one end of the first capacitor being electrically connected with one end of the first secondary winding, the cathode of the first diode being electrically connected with the other end of the first capacitor, one end of the first resistor being electrically connected with the anode of the first diode, the other end of the first resistor being electrically connected with the other end of the first secondary winding, one end of the second resistor being electrically connected with the other end of the first capacitor and the cathode of the first diode, one end of the third resistor being electrically connected with the other end of the second resistor, and the other end of the third resistor being grounded; a sampling signal output port is arranged at the connection node of the second resistor and the third resistor.

2. The voltage sampling circuit of claim 1, wherein, the electric signal processing module comprises: a rectification unit electrically connected with the power supply and configured to rectify the power supply; a sixth capacitor electrically connected with the rectification unit, one end of the sixth capacitor being electrically connected with one end of the primary winding and one end of the inverter circuit, respectively, and the other end of the sixth capacitor being electrically connected with one end of the switch module and the other end of the inverter circuit, respectively, the sixth capacitor being configured to filter the rectified power supply.

3. The voltage sampling circuit of claim 2, wherein, the switch module comprises: A pressure control current element, a drain of the pressure control current element is used for being electrically connected with another end of the primary winding, a source of the pressure control current element is used for being electrically connected with another end of the sixth capacitor, a gate of the pressure control current element is used for receiving a switching signal, and the pressure control current element is used for being turned on or turned off according to the switching signal.

4. Servo drive, characterized in that The servo driver is applied to a servo motor, and the servo driver comprises: The voltage sampling circuit according to any one of claims 1 to 3; An inverter circuit, which is electrically connected with the electric signal processing module and the servo motor respectively.

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