Method and device for controlling a two-wire discharge circuit of a battery

Abstract

Method for controlling a two-wire discharge circuit of a battery, which includes: Determine (201) a positive bus voltage and a negative bus voltage in the two-wire discharge circuit of the battery and compare the positive bus voltage with the negative bus voltage to obtain an initial voltage difference signal; Rules (202) of the first voltage difference signal using a proportional-integral PI controller to obtain a first pulse width modulation PWM signal; for each of the first discharge branches in the two-wire discharge circuit of the battery, taking (203) a sum of the first PWM signal and a determined initial master control PWM signal corresponding to the first discharge branch as the set master control PWM signal corresponding to the first discharge branch, and performing (204) a drive on a switching transistor to control a charge-discharge time of a bus capacitor in the first discharge branch by means of the set master control PWM signal corresponding to the first discharge branch, wherein one terminal of the first discharge branch is connected to a positive electrode of a power supply in the two-wire discharge circuit of the battery and the other terminal of the first discharge branch is connected to a system neutral point; and For each of the second discharge branches in the two-wire discharge circuit of the battery, take (203) a difference between a determined initial master control PWM signal corresponding to the second discharge branch and the first PWM signal as the set master control PWM signal corresponding to the second discharge branch, and perform (204) a drive on a switching transistor to control a charge-discharge time of a bus capacitor in the second discharge branch by means of the set master control PWM signal corresponding to the second discharge branch, wherein one terminal of the second discharge branch is connected to a negative electrode of the power supply in the two-wire discharge circuit of the battery and the other terminal of the second discharge branch is connected to the system neutral point, wherein for each of the discharge branches the initial master control PWM signal corresponding to the discharge branch is obtained by controlling the two-wire discharge circuit of the battery in the manner of a double-loop control having a full bus voltage outer loop and a closed loop of an average value of inductance currents in the two-wire discharge circuit of the battery, or by controlling the discharge branch in the manner of a double-loop control having a full bus voltage outer loop and a closed loop of an actual value of an inductance current in the discharge branch.

Description

[0001] This application claims priority to Chinese Patent Application No. 201510149737.4 (WO 2016 / 155 651 A1) entitled "METHOD AND DEVICE FOR CONTROLLING TWO-WIRE DISCHARGE CIRCUIT OF BATTERY" and filed with the Chinese State Intellectual Property Office on March 31, 2015, which is incorporated herein by reference in its entirety. SUBJECT AREA

[0002] The present disclosure relates to the technical field of circuit control and, more particularly, to a method and apparatus for controlling a two-wire discharge circuit of a battery. STATE OF THE ART

[0003] Currently, in order to save costs for a battery discharge circuit, a two-wire battery discharge circuit, which does not require the battery neutral connection, has been proposed in the industry based on a three-wire discharge circuit, such as the Vienna circuit or a circuit essentially similar to the Vienna circuit. As described in Fig. 1, which is a schematic structural diagram of the two-wire circuit of the battery, the two-wire discharge circuit of the battery may include: a power supply (i.e., a battery); a positive bus capacitor C1 and a negative bus capacitor C2 connected to a system neutral point N; three first discharge branches, one terminal of each of the first discharge branches being connected to a positive terminal (Ba+) of the battery and the other terminal being connected to a system neutral point N; and three second discharge branches, one terminal of each of the second discharge branches being connected to a negative terminal (Bat-) of the battery and the other terminal being connected to the system neutral point N.

[0004] Each of the first discharge branches may include a first thyristor, a first inductance L1, a first switching transistor T1, a first freewheeling diode D1, and a first diode connected in parallel with the first switching transistor T1.In each of the first discharge branches, an anode of the first thyristor is connected to the positive electrode of the battery, a cathode of the first thyristor is connected to a first terminal of the first inductor L1, a second terminal (not connected to the first thyristor) of the first inductor L1 is connected to a collector of the first switching transistor T1, an emitter of the first switching transistor T1 is connected to the system neutral point N, an anode of the first freewheeling diode D1 is connected to the second terminal of the first inductor L1, a cathode of the first freewheeling diode D1 is connected to a non-system neutral point of the positive bus capacitor C1, an anode of the first diode is connected to the emitter of the first switching transistor T1, and a cathode of the first diode is connected to the collector of the first diode T1.It should also be noted that the two-wire discharge circuit of the battery may have three first discharge branches, each corresponding to the three phases A, B, and C. Furthermore, to simplify the distinction, in . Fig. 1, the first inductor L1, the first switching transistor T1, the first freewheeling diode D1, and other electronic elements in the first discharge branch corresponding to phase A may be referred to as LA1, TA1, DA1, and the like, respectively; the first inductor L1, the first switching transistor T1, the first freewheeling diode D1, and other electronic elements in the first discharge branch corresponding to phase B may be referred to as LB1, TB1, DB1, and the like, respectively; and the first inductor L1, the first switching transistor T1, the first freewheeling diode D1, and other electronic elements in the first discharge branch corresponding to phase C may be referred to as LC1, TC1, DC1, and the like, which are not described multiple times in the present disclosure.

[0005] In substantially the same manner, each of the second discharge branches may comprise a second thyristor, a second inductance L2, a second switching transistor T2, a second freewheeling diode D2 and a second diode connected in parallel with the second switching transistor T2.In each of the second discharge branches, a cathode of the second thyristor is connected to the negative electrode of the battery, an anode of the first thyristor is connected to a first terminal of the second inductor L2, a second terminal (not connected to the second thyristor) of the second inductor L2 is connected to an emitter of the second switching transistor T2, a collector of the second switching transistor T2 is connected to the system neutral point N, a cathode of the second freewheeling diode D2 is connected to the second terminal of the second inductor L2, an anode of the second freewheeling diode D2 is connected to a non-system neutral point of the negative bus capacitor C2, an anode of the second diode is connected to the emitter of the second switching transistor T2, and a cathode of the second diode is connected to the collector of the second switching transistor T2.It should be noted that the two-wire discharge circuit of the battery may have three second discharge branches, corresponding respectively to the three phases A, B, and C. Furthermore, to simplify the distinction in . Fig. 1, the second inductor L2, the second switching transistor T2, the second freewheeling diode D2, and other electronic elements in the second discharge branch corresponding to phase A may be referred to as LA2, TA2, DA2, and the like, respectively; the second inductor L2, the second switching transistor T2, the second freewheeling diode D2, and other electronic elements in the second discharge branch corresponding to phase B may be referred to as LB2, TB2, DB2, and the like, respectively; and the second inductor L2, the second switching transistor T2, the second freewheeling diode D2, and other electronic elements in the second discharge branch corresponding to phase C may be referred to as LC2, TC2, DC2, and the like, which are not described multiple times in the present disclosure.

[0006] It should also be noted that the Fig. 1 may refer to a PFC (Power Factor Correction) inductance, which is not described multiple times in the present disclosure.

[0007] In the two-wire discharge circuit of the battery, which is Fig. As shown in Figure 1, a boost function can be realized without the battery's neutral wire connection. Taking phase A as an example, two PFC inductors, two switching transistors, two freewheeling diodes, and the like can work in total in an ideal situation in the first discharge branch and the second discharge branch, respectively, with the positive bus capacitor and the negative bus capacitor. The battery can store energy using the PFC inductors when the switching transistors are turned on, and the battery and PFC inductors can charge the bus capacitors via the freewheeling capacitors when the switching transistors are turned off, thus realizing the boost function. Furthermore, in a case of three-phase control, the three phases can be shifted by 120 degrees, thus greatly reducing the battery current ripple and improving the circuit performance.

[0008] Patent application CN 1 03 916 008 A discloses an output capacitance voltage division control system for a three-level DC-DC converter.The output capacitance voltage division control system includes an analog PV power supply for powering a DC-DC boost converter and is characterized in that voltage and current signals from the input end of the DC-DC boost converter are sent to an input conditioning circuit; voltage signals from the output end of the DC-DC boost converter are sent to an output conditioning circuit; the signal output end of the input conditioning circuit and the signal output end of the output conditioning circuit are both connected to the signal input end of a digital signal processor; the signal output end of the digital signal processor is connected to a drive circuit; the drive circuit controls the turning on or off of power tubes in the DC-DC boost converter.Such a system can solve the problem of mid-frequency unbalance caused by mismatches in modulation strategies, circuit parameters, and drive delay.

[0009] In practice, however, the two-wire battery discharge circuit is unable to operate in an ideal mode, as various factors can exert negative effects on the two-wire battery discharge circuit. For example, in a case where the switching transistors in the circuit have different delays, a bus voltage imbalance issue may occur, leading to abnormal circuit operation and degrading circuit performance. Therefore, it is imperative to provide a circuit control solution for the two-wire battery discharge circuit to solve the aforementioned problems. INVENTION

[0010] A method and apparatus for controlling a two-wire discharge circuit of a battery according to embodiments of the present disclosure are provided to solve the problem of low circuit performance caused by bus voltage unbalance in the two-wire discharge circuit of the battery.

[0011] A method of controlling a two-wire discharge circuit according to an embodiment of the present disclosure is provided, comprising: Determining a positive bus voltage and a negative bus voltage in the two-wire discharge circuit of the battery and comparing the positive bus voltage with the negative bus voltage to obtain a first voltage difference signal; Controlling the first voltage difference signal by means of a PI (proportional-integral) controller to obtain a first PWM (pulse-width modulation) signal; for each of the first discharge branches in the two-wire discharge circuit of the battery, taking a sum of the first PWM signal and a determined initial master control PWM signal corresponding to the first discharge branch as a set master control PWM signal corresponding to the first discharge branch, and driving a switching transistor to control a charge-discharge period of a bus capacitor in the first discharge branch by means of the set master control PWM signal corresponding to the first discharge branch, wherein one terminal of the first discharge branch is connected to a positive electrode of a power supply in the two-wire discharge circuit of the battery and the other terminal of the first discharge branch is connected to a system neutral point; and for each of the second discharge branches in the two-wire discharge circuit of the battery, taking a difference between a determined initial master control PWM signal corresponding to the second discharge branch and the first PWM signal as a set master control PWM signal corresponding to the second discharge branch, and performing drive control on a switching transistor for controlling a charge-discharge period of a bus capacitor in the second discharge branch using the set master control PWM signal corresponding to the second discharge branch, wherein one terminal of the second discharge branch is connected to a negative electrode of the power supply in the two-wire discharge circuit of the battery and the other terminal of the second discharge branch is connected to the system neutral point, wherein, for each of the discharge branches, the initial master control PWM signal corresponding to the discharge branch is obtained by controlling the two-wire discharge circuit of the battery in a double-loop control manner having a full-bus voltage outer loop and a closed loop of an average value of inductance currents in the two-wire discharge circuit of the battery, or by controlling the discharge branch in a double-loop control manner having a full-bus voltage outer loop and a closed loop of an actual value of an inductance current in the discharge branch.

[0012] In addition, there is further provided an apparatus for controlling a two-wire discharge circuit of a battery according to an embodiment of the present disclosure, comprising: an initial signal detection module configured to: obtain, for each of the discharge branches in the two-wire battery discharge circuit, an initial master control PWM signal corresponding to the discharge branch by controlling the two-wire battery discharge circuit in a dual-loop control manner having a full bus voltage outer loop and a closed loop of an average value of inductance currents in the two-wire discharge circuit of the battery, or by controlling the discharge branch in the manner of a double-loop control having a full-bus voltage outer loop and a closed loop of an actual value of an inductance current in the discharge branch; a fine-tuning signal detection module configured to: detect a positive bus voltage and a negative bus voltage in the two-wire discharge circuit of the battery, compare the positive bus voltage with the negative bus voltage to obtain a first voltage difference signal, and control the first voltage difference signal using a PI controller to obtain a first PWM signal; for each of the first discharge branches in the two-wire discharge circuit of the battery, take a sum of the first PWM signal and the detected initial master control PWM signal corresponding to the first discharge branch as an adjusted master control PWM signal corresponding to the first discharge branch, wherein one terminal of the first discharge branch is connected to a positive electrode of a power supply in the two-wire discharge circuit of the battery, and the other terminal of the first discharge branch is connected to a system neutral point;and for each of the second discharge branches in the two-wire discharge circuit of the battery, taking a difference between the determined initial master control PWM signal corresponding to the second discharge branch and the first PWM signal as the adjusted master control PWM signal corresponding to the second discharge branch, wherein one terminal of the second discharge branch is connected to a negative electrode of the power supply in the two-wire discharge circuit of the battery and the other terminal of the second discharge branch is connected to the system neutral point; and; a circuit drive control module configured to perform, for each of the discharge branches in the two-wire discharge circuit of the battery, a drive on a switching transistor for controlling a charge-discharge period of a bus capacitor in the discharge branch by means of the set master control PWM signal corresponding to the discharge branch.

[0013] The present disclosure provides the following advantageous effects.

[0014] A method and apparatus for controlling a two-wire discharge circuit of a battery according to embodiments of the present disclosure are provided. In the technical solution according to embodiments of the present disclosure, a full-bus voltage outer loop and a closed loop of an average value of inductance currents or an actual value of an inductance current are taken as the master control loop of the two-wire discharge circuit of the battery. In this way, energy symmetry can be realized while ensuring a stable full-bus voltage. Even in a case where the master control loop controls an output, a duty ratio of a switching transistor in each of the discharge branches is adjusted to control the circuit to independently charge / discharge a half-bus corresponding to the discharge branch, thereby balancing the bus voltage.while achieving energy symmetry, and further maintaining technical indicators in the three-wire connection of the battery, while eliminating the neutral wire connection of the battery and without adding any further circuitry, and improving the circuit performance of the two-wire discharge circuit of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] To better illustrate the technical solution in the embodiments of the present disclosure, the drawings necessary for describing the embodiments are presented below in a simple manner. The drawings illustrate some embodiments of the disclosure in the following description. Those skilled in the art can also obtain other drawings according to the drawings without creative work. Fig. Figure 1 is a possible schematic structural representation of an existing two-wire discharge circuit of a battery; Fig. 2 is a schematic flow diagram of a method for controlling a two-wire discharge circuit of a battery according to a first embodiment of the present disclosure; Fig. 3 is a first schematic diagram of an entire control circuit corresponding to the method of controlling the two-wire discharge circuit of the battery according to the embodiment of the present disclosure; Fig. 4 is a schematic diagram of a circuit of a dual-loop control type having a full bus voltage outer loop and a closed loop of average inductor currents, according to the embodiment of the present disclosure; Fig. 5 is a schematic diagram of a circuit of a dual-loop control type having a full-bus voltage outer loop and a closed loop of an actual value of an inductor current, according to the embodiment of the present disclosure; Fig. 6 is a second schematic diagram of an entire control circuit corresponding to the method of controlling the two-wire discharge circuit of the battery according to the embodiment of the present disclosure; Fig. 7 is a third schematic diagram of an entire control circuit corresponding to the method for controlling the two-wire discharge circuit of the battery according to the embodiment of the present disclosure; and Fig. 8 is a schematic structural diagram of an apparatus for controlling a two-wire discharge circuit of a battery according to a second embodiment of the present disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] To more clearly illustrate the object, technical solution, and advantages of the present disclosure, the present disclosure will be explained in more detail below in conjunction with the drawings. The described embodiments represent only a portion of the embodiments of the present disclosure and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative work fall within the scope of the present disclosure. First embodiment

[0017] A method for controlling a two-wire discharge circuit of a battery according to a first embodiment of the present disclosure is provided as in Fig. 2, which is a schematic flow diagram of a method for controlling a two-wire discharge circuit of a battery according to a first embodiment of the present disclosure, the method comprising steps 201 to 204.

[0018] In step 201, a positive bus voltage and a negative bus voltage are determined in the two-wire discharge circuit of the battery, and the positive bus voltage is compared with the negative bus voltage to obtain a first voltage difference signal.

[0019] The determined positive bus voltage and the determined negative bus voltage respectively refer to an actual positive bus voltage and an actual negative bus voltage, which are not described repeatedly in the embodiment of the present disclosure. Furthermore, the first voltage difference signal is obtained by subtracting the negative bus voltage from the positive bus voltage, which is not described repeatedly in the embodiment of the present disclosure.

[0020] In step 202, the first voltage difference signal is controlled by a PI controller to obtain a first PWM signal.

[0021] In step 203, for each of the first discharge branches in the battery's two-wire discharge circuit, a sum of the first PWM signal and a determined initial master control PWM signal corresponding to the first discharge branch is taken as the adjusted master control PWM signal corresponding to the first discharge branch. For each of the second discharge branches in the battery's two-wire discharge circuit, a difference between a determined initial master control PWM signal corresponding to the second discharge branch and the first PWM signal is taken as the adjusted master control PWM signal corresponding to the second discharge branch.

[0022] One terminal of the first discharge branch is connected to a positive electrode of a power supply in the battery's two-wire discharge circuit, and the other terminal of the first discharge branch is connected to a system neutral point. One terminal of the second discharge branch is connected to a negative electrode of the power supply in the battery's two-wire discharge circuit, and the other terminal of the second discharge branch is connected to the system neutral point.

[0023] Furthermore, for each of the discharge branches, the initial master control PWM signal corresponding to the discharge branch can be obtained by controlling the two-wire battery discharge circuit in a double-loop control manner, which has a full-bus voltage outer loop and a closed loop of an average value of inductance currents (the average value of the inductance currents refers to an average value of actual values ​​of inductance currents of all discharge branches in the two-wire battery discharge circuit, that is, an average value of inductance currents in the two-wire battery discharge circuit). Alternatively, the initial master control PWM signal corresponding to the discharge branch can be obtained by controlling the discharge branch in a double-loop control manner, which has a full-bus voltage outer loop and a closed loop of an actual value of an inductance current in the discharge branch.

[0024] In step 204, for each of the discharge branches, a control is performed on a switching transistor for controlling a charge-discharge period of a bus capacitor in the discharge branch by means of the set master control PWM signal corresponding to the discharge branch.

[0025] If you look at the two-wire discharge circuit of the battery, which is Fig. 1 as an example, for each of the discharge branches, the set master control PWM signal corresponding to the discharge branch is input to a base of a TA transistor in the discharge branch to perform drive control on the TA transistor.

[0026] That is, in the technical solution according to the embodiments of the present disclosure, a full-bus voltage outer loop and a closed loop of an average value of inductance currents or an actual value of an inductance current are taken as the master control loop of the two-wire discharge circuit of the battery. In this way, energy balance can be realized while ensuring a stable full-bus voltage. Even in a case where the master control loop controls an output, a duty ratio of a switching transistor in each of the discharge branches is adjusted to control the circuit to independently charge / discharge a half-bus corresponding to the discharge branch, thereby balancing the bus voltage while realizing energy balance, and further maintaining technical indicators in the three-wire connection of the battery.while eliminating the battery neutral connection and without adding any additional circuitry, and improving the circuit performance of the battery's two-wire discharge circuit.

[0027] If you look at the two-wire discharge circuit of the battery, which is Fig. 1 as an example, as in Fig. 3 is shown, which is a schematic diagram (a first schematic diagram of an entire control circuit) of an entire control circuit corresponding to the method for controlling the two-wire discharge circuit of the battery according to the first embodiment of the present disclosure, in which U dc-p a determined positive bus voltage, U dc-n a determined negative bus voltage, U pnCtr denotes a first PWM signal, MainCtrA1, MainCtrB1, MainCtrC1, MainCtrA2, MainCtrB2 and MainCtrC2 respectively denote an initial master control PWM signal corresponding to a first A-phase discharge branch, an initial master control PWM signal corresponding to a first B-phase discharge branch, an initial master control PWM signal corresponding to a first C-phase discharge branch, an initial master control PWM signal corresponding to a second A-phase discharge branch, an initial master control PWM signal corresponding to a second B-phase discharge branch and an initial master control PWM signal corresponding to a second C-phase discharge branch in the two-wire discharge circuit of the battery.PWM_A1, PWM_B1, PWM_C1, PWM_A2, PWM_B2, and PWM_C2 respectively denote a set master control PWM signal corresponding to the first A-phase discharge branch, a set master control PWM signal corresponding to the first B-phase discharge branch, a set master control PWM signal corresponding to the first C-phase discharge branch, a set master control PWM signal corresponding to the second A-phase discharge branch, a set master control PWM signal corresponding to the second B-phase discharge branch, and a set master control PWM signal corresponding to the second C-phase discharge branch in the two-wire discharge circuit of the battery.

[0028] It should be noted that in a case where the initial master control PWM signal corresponding to each of the discharge branches is obtained by controlling the two-wire discharge circuit of the battery in the manner of double-loop control including the full-bus voltage outer loop and the closed loop of an average value of the inductance currents in the two-wire discharge circuit of the battery, MainCtrA1, MainCtrB1, MainCtrC1, MainCtrA2, MainCtrB2, and MainCtrC2 may be a same master control signal MainCtr, which is not described multiple times in the embodiment of the present disclosure.

[0029] It should be further noted that according to an analysis of an operation principle of the circuit, a duty ratio of a switching transistor is decreased to increase a half-bus voltage corresponding to the switching transistor, which is opposite to an operation principle of boosting, otherwise a positive feedback is formed in the circuit.Therefore, in the embodiment of the present disclosure, for each of the first discharge branches in the two-wire discharge circuit of the battery, the sum of the first PWM signal and the detected initial master control PWM signal corresponding to the first discharge branch is taken as the adjusted master control PWM signal corresponding to the first discharge branch. Also, for each of the second discharge branches in the two-wire discharge circuit of the battery, a difference between the detected initial master control PWM signal corresponding to the second discharge branch and the first PWM signal is taken as the adjusted master control PWM signal corresponding to the second discharge branch, which is not described multiple times in the embodiment of the present disclosure.

[0030] Alternatively, in a case where, for each of the discharge branches, the initial master control PWM signal corresponding to the discharge branch is obtained by controlling the two-wire discharge circuit of the battery in the manner of a double-loop control having a full-bus voltage outer loop and a closed loop of an average value of inductance currents, the initial master control PWM signal corresponding to the discharge branch is determined by: Comparing a sum of the detected positive bus voltage and the detected negative bus voltage in the two-wire discharge circuit of the battery with a predetermined value of a predetermined bus voltage to obtain a second voltage difference signal; Controlling the second voltage difference signal by means of a PI controller to obtain a predetermined value of an inductance current; Comparing the predetermined value of the inductance current with an average value of inductance currents in the two-wire discharge circuit of the battery to obtain a first current difference signal; and Controlling the first current difference signal by means of a PI controller to obtain a second PWM signal, and taking a sum of the second PWM signal and a predetermined feedforward signal as an initial master control PWM signal corresponding to the discharge tap.

[0031] A schematic diagram showing a circuit corresponding to the type of double loop control having the full bus voltage outer loop and the closed loop of the mean value of the inductance currents can be shown as in Fig. 4 shown, in the U dc_p a determined positive bus voltage, U dc_n a determined negative bus voltage, U dc* denotes a predetermined value of a predetermined bus voltage (which is set and determined according to actual situations and is not described multiple times in the embodiment of the present disclosure), I L_mean an average value of inductance currents in the two-wire discharge circuit of the battery, 1-U batt / U dc * denotes a predetermined feedforward signal, U batt a power supply voltage of a power supply in the two-wire discharge circuit of the battery, and MainCtr denotes an initial master control PWM signal corresponding to the discharge branch.

[0032] Furthermore, in a case where, for each of the discharge branches, the initial master control PWM signal corresponding to the discharge branch is obtained by controlling the discharge branch in the manner of a double-loop control having a full-bus voltage outer loop and a closed loop of an actual value of an inductor current, the initial master control PWM signal corresponding to the discharge branch is determined by: Comparing a sum of the detected positive bus voltage and the detected negative bus voltage in the two-wire discharge circuit of the battery with a predetermined value of a predetermined bus voltage to obtain a second voltage difference signal; Controlling the second voltage difference signal by means of a PI controller to obtain a predetermined value of an inductance current; Comparing the predetermined value of the inductance current with an actual value of the inductance current in the discharge branch to obtain a second current difference signal; and Controlling the second current difference signal by means of a PI controller to obtain a third PWM signal, and taking a sum of the third PWM signal and a predetermined feedforward signal as an initial master control PWM signal corresponding to the discharge tap.

[0033] Assuming that a schematic structural representation of the two-wire discharge circuit of the battery as shown in Fig. 1 may be implemented, a schematic diagram showing a circuit corresponding to the type of double loop control having the full bus voltage outer loop and the closed loop of the actual value of the inductor current, as shown in Fig. 5 shown, in the U dc_pa determined positive bus voltage, U dc_n a determined negative bus voltage, U dc * denotes a given value of a predetermined bus voltage, 1-U batt / U dc * denotes a predetermined feedforward signal, U batt a power supply voltage of a power supply in the two-wire discharge circuit of the battery, I LA1 ,I LB1 ,I LC1 ,I LA2 , I LB2 and I LC2respectively denote an actual value of an inductance current in a first A-phase discharge branch, an actual value of an inductance current in a first B-phase discharge branch, an actual value of an inductance current in a first C-phase discharge branch, an actual value of an inductance current in a second A-phase discharge branch, an actual value of an inductance current in a second B-phase discharge branch, and an actual value of an inductance current in a second C-phase discharge branch in the two-wire discharge circuit of the battery, and MainCtrA1, MainCtrB1, MainCtrC1, MainCtrA2, MainCtrB2, and MainCtrC2 each denote an initial master control PWM signal corresponding to the first A-phase discharge branch, an initial master control PWM signal corresponding to the first B-phase discharge branch, a Initial master control PWM signal corresponding to the first C-phase discharge branch, an initial master control PWM signal,corresponding to the second A-phase discharge branch, an initial master control PWM signal corresponding to the second B-phase discharge branch, and an initial master control PWM signal corresponding to the second C-phase discharge branch in the two-wire discharge circuit of the battery.

[0034] In addition, on the basis of the Fig. 2 is a schematic diagram showing an entire control circuit (i.e., a second schematic diagram of the entire control circuit) corresponding to the method for controlling the two-wire discharge circuit of the battery according to the first embodiment of the present disclosure, may be implemented as shown in Fig. 6, in which the initial master control PWM signal corresponding to each of the discharge branches is determined by means of U pnCtr (first PWM signal) is fine-tuned to obtain a set master control PWM signal corresponding to the discharge branch. In Fig. 6, PWM_A1, PWM_B1, PWM_C1, PWM_A2, PWM_B2, and PWM_C2 respectively denote a set master control PWM signal corresponding to the first A-phase discharge branch, a set master control PWM signal corresponding to the first B-phase discharge branch, a set master control PWM signal corresponding to the first C-phase discharge branch, a set master control PWM signal corresponding to the second A-phase discharge branch, a set master control PWM signal corresponding to the second B-phase discharge branch, and a set master control PWM signal corresponding to the second C-phase discharge branch, which are not described multiple times in the embodiment of the present invention.

[0035] It should be noted that in a case where the initial master control PWM signal corresponding to each of the discharge branches is obtained by controlling the discharge circuit in the double-loop control manner including the full-bus voltage outer loop and the closed loop of the actual value of the inductor current in the discharge circuit, the actual value of the inductor current in the discharge branch is adjusted by means of the obtained predetermined value of the inductor current to realize current sharing for the inductor current and further reduce discharge ripples of the battery and improve circuit performance.

[0036] It should also be noted that assuming a schematic structural representation of the two-wire discharge circuit of the battery as shown in Fig. 1, in a case where the initial master control PWM signal corresponding to the discharge branch is obtained by controlling the discharge circuit in the manner of a double-loop control having the full-bus voltage outer loop and the closed loop of the actual value of the inductance current in the discharge circuit, since a control degree of freedom of an inner-loop inductance current is 5, six inductance currents or five inductance currents are introduced to realize an equal control effect, that is, the number of control branches in the in Fig. 6 may be six or five (i.e., a control branch corresponding to a discharge branch may be removed), which is not limited in the embodiment of the present disclosure.

[0037] Furthermore, in a case where, for each of the discharge branches, the initial master control PWM signal corresponding to the discharge branch is obtained by controlling the two-wire discharge circuit of the battery in the manner of a double-loop control having the full-bus voltage outer loop and the closed loop of the average value of the inductance currents in the two-wire discharge circuit of the battery, the method further comprises: for each of the discharge branches in the two-wire discharge circuit of the battery

[0038] Comparing the mean value of the inductance currents in the two-wire discharge circuit of the battery with the actual value of the inductance current in the discharge branch to obtain a third current difference signal;

[0039] Controlling the third current difference signal using a PI controller to obtain a fourth PWM signal; and

[0040] Adding the fourth PWM signal and the adjusted master control PWM signal corresponding to the discharge branch to obtain a newly adjusted master control PWM signal corresponding to the discharge branch, and driving a switching transistor for controlling a charge-discharge period of a bus capacitor in the discharge branch by means of the newly adjusted master control PWM signal corresponding to the discharge branch.

[0041] In a case where the initial master control PWM signal corresponding to the discharge branch is obtained by controlling the two-wire discharge circuit of the battery in the double-loop control manner having the full-bus voltage outer loop and the closed loop of the average value of the inductor currents for each of the discharge branches, a PWM signal obtained by performing PI control on a difference between the average value of the inductor currents and the actual value of the inductor current in the discharge branch is taken as a fine adjustment amount of a modulation wave of the discharge branch, and the fine adjustment amount is added to a control amount of a duty ratio of a switching transistor in the discharge branch to realize current sharing of the inductor current and further reduce discharge ripples of the battery and improve the performance of the circuit.

[0042] Assuming that a schematic structural representation of the two-wire discharge circuit of the battery as shown in Fig. 1 is a schematic diagram of an entire control circuit (i.e., a third schematic diagram of the entire control circuit) corresponding to the method for controlling the two-wire discharge circuit of the battery according to the first embodiment of the present disclosure, in Fig. 7 shown in the I LA1 , I LB1 , I LC1 , I LA2 , I LB2 and I LC2respectively denote an actual value of an inductance current in the first A-phase discharge branch, an actual value of an inductance current in the first B-phase discharge branch, an actual value of an inductance current in the first C-phase discharge branch, an actual value of an inductance current in a second A-phase discharge branch, an actual value of an inductance current in the second B-phase discharge branch, and an actual value of an inductance current in the second C-phase discharge branch in the two-wire discharge circuit of the battery. I L_mean denotes an average value of the inductance currents in the two-wire discharge circuit of the battery.

[0043] I LA1 Ctr, I LB1 Ctr, I LC1 Ctr, I LA2 Ctr, I LB2 Ctr and I LC2Ctr respectively denote a fourth PWM signal corresponding to the first A-phase discharge branch, a fourth PWM signal corresponding to the first B-phase discharge branch, a fourth PWM signal corresponding to the first C-phase discharge branch, a fourth PWM signal corresponding to the second A-phase discharge branch, a fourth PWM signal corresponding to the second B-phase discharge branch, and a fourth PWM signal corresponding to the second C-phase discharge branch in the two-wire discharge circuit of the battery.

[0044] PWM_A1, PWM_B1, PWM_C1, PWM_A2, PWM_B2, and PWM_C2 respectively denote a set master control PWM signal corresponding to the first A-phase discharge branch, a set master control PWM signal corresponding to the first B-phase discharge branch, a set master control PWM signal corresponding to the first C-phase discharge branch, a set master control PWM signal corresponding to the second A-phase discharge branch, a set master control PWM signal corresponding to the second B-phase discharge branch, and a set master control PWM signal corresponding to the second C-phase discharge branch in the two-wire discharge circuit of the battery.

[0045] PWM_A1', PWM_B1', PWM_C1', PWM_A2', PWM_B2', and PWM_C2' respectively denote a newly adjusted master control PWM signal corresponding to the first A-phase discharge branch, a newly adjusted master control PWM signal corresponding to the first B-phase discharge branch, a newly adjusted master control PWM signal corresponding to the first C-phase discharge branch, a newly adjusted master control PWM signal corresponding to the second A-phase discharge branch, a newly adjusted master control PWM signal corresponding to the second B-phase discharge branch, and a newly adjusted master control PWM signal corresponding to the second C-phase discharge branch in the two-wire discharge circuit of the battery.

[0046] The method for controlling the two-wire discharge circuit of the battery is provided according to the first embodiment of the present disclosure. In the technical solution according to the first embodiment of the present disclosure, a full-bus voltage outer loop and a closed loop of an average value of inductance currents or an actual value of an inductance current are taken as the master control loop of the two-wire discharge circuit of the battery. In this way, energy balance can be realized while ensuring a stable full-bus voltage. Even in a case where the master control loop controls an output, a duty ratio of a switching transistor in each of the discharge branches is adjusted to control the circuit to independently charge / discharge a half-bus corresponding to the discharge branch, thereby balancing the bus voltage while realizing energy balance.and further maintaining technical indicators in the three-wire connection of the battery while eliminating the neutral connection of the battery and without adding any additional circuitry, and improving the circuit performance of the two-wire discharge circuit of the battery.

[0047] Furthermore, in the technical solution according to the first embodiment of the present disclosure, for each of the discharge branches, a PWM signal obtained by performing PI control on a difference between the average value of the inductor currents and the actual value of the inductor current in the discharge branch is taken as a fine adjustment amount of a modulation wave of the discharge branch, and the fine adjustment amount is added to a control amount of a duty ratio of a switching transistor in the discharge branch to realize current sharing of the inductor current while equalizing the bus voltage, and further reduce discharge ripples of the battery and improve the performance of the circuit. Second embodiment

[0048] Based on a similar inventive concept, a device for controlling a two-wire discharge circuit of a battery according to a second embodiment of the present disclosure is provided. When implementing the device, reference may be made to the related description of the first embodiment of the present disclosure, and repetition is not omitted here. As in Fig. 8, which is a schematic structural diagram of an apparatus for controlling a two-wire discharge circuit of a battery according to the second embodiment of the present disclosure, the apparatus may include an initial signal detection module 81, a fine-tuned signal detection module 82, and a circuit drive control module 83.

[0049] The initial signal determination module 81 is configured to: obtain, for each of the discharge branches in the two-wire battery discharge circuit, an initial master control PWM signal corresponding to the discharge branch by controlling the two-wire battery discharge circuit in a double-loop control manner having a full-bus voltage outer loop and a closed loop of an average value of inductance currents in the two-wire battery discharge circuit, or by controlling the discharge branch in a double-loop control manner having a full-bus voltage outer loop and a closed loop of an actual value of an inductance current in the discharge branch.

[0050] The fine-tuning signal detection module 82 is configured to: detect a positive bus voltage and a negative bus voltage in the two-wire discharge circuit of the battery, compare the positive bus voltage with the negative bus voltage to obtain a first voltage difference signal; and control the first voltage difference signal using a PI controller to obtain a first PWM signal; for each of the first discharge branches in the two-wire discharge circuit of the battery, take a sum of the first PWM signal and the detected initial master control PWM signal corresponding to the first discharge branch as the adjusted master control PWM signal corresponding to the first discharge branch, wherein one terminal of the first discharge branch is connected to a positive electrode of a power supply in the two-wire discharge circuit of the battery and the other terminal of the first discharge branch is connected to a system neutral point;and for each of the second discharge branches in the two-wire discharge circuit of the battery, taking a difference between the determined initial master control PWM signal corresponding to the second discharge branch and the first PWM signal as the adjusted master control PWM signal corresponding to the second discharge branch, wherein one terminal of the second discharge branch is connected to a negative electrode of the power supply in the two-wire discharge circuit of the battery and the other terminal of the second discharge branch is connected to a system neutral point;

[0051] The circuit drive control module 83 is configured for each of the discharge branches in the two-wire discharge circuit of the battery to perform drive control on a switching transistor for controlling a discharge-charge period of a bus capacitor in the discharge branch by means of the set master control PWM signal corresponding to the discharge branch.

[0052] Optionally, the initial signal determination module 81 may be configured to: compare a sum of the detected positive bus voltage and the detected negative bus voltage in the two-wire discharge circuit of the battery with a predetermined value of a predetermined bus voltage to obtain a second voltage difference signal; control the second voltage difference signal using a PI controller to obtain a predetermined value of an inductor current; compare the predetermined value of the inductor current with the average value of inductor currents in the two-wire discharge circuit of the battery to obtain a first current difference signal; control the first current difference signal using a PI controller to obtain a second PWM signal; and take a sum of the second PWM signal and a predetermined feedforward signal as an initial master control PWM signal corresponding to the discharge tap in the two-wire discharge circuit of the battery.

[0053] Furthermore, the initial signal determination module 81 may be particularly configured to: compare a sum of the determined positive bus voltage and the determined negative bus voltage in the two-wire discharge circuit of the battery with a predetermined value of a predetermined bus voltage to obtain a second voltage difference signal; regulate the second voltage difference signal by means of a PI controller to obtain a predetermined value of an inductor current; and for each of the discharge branches, compare the predetermined value of the inductor current with an actual value of an inductor current in the discharge branch to obtain a second current difference signal, regulate the second current difference signal by means of a PI controller to obtain a third PWM signal, and take a sum of the third PWM signal and a predetermined feedforward signal as an initial master control PWM signal corresponding to the discharge branch.

[0054] In addition, the fine-tuned signal detection module 82 may be further configured to: for each of the discharge branches, in a case where the initial master control PWM signal corresponding to the discharge branch is obtained by controlling the two-wire battery discharge circuit in a double-loop control manner including the full-bus voltage outer loop and the closed loop of an average value of the inductance currents in the two-wire battery discharge circuit, compare the average value of the inductance currents in the two-wire battery discharge circuit with the actual value of the inductance current in the discharge branch to obtain a third current difference signal; regulate the third current difference signal by means of a PI controller to obtain a fourth PWM signal;and adding the fourth PWM signal and the adjusted master control PWM signal corresponding to the discharge branch to obtain a newly adjusted master control PWM signal corresponding to the discharge branch.;

[0055] Accordingly, the circuit drive control module 83 may be further configured to perform, for each of the discharge branches of the two-wire discharge circuit of the battery, a drive control on a switching transistor for controlling a charge-discharge period of a bus capacitor in the discharge branch by means of the newly adjusted master control PWM signal corresponding to the discharge branch.

[0056] The specified feedforward signal is 1-U batt / U dc * denotes U batt denotes a power supply voltage of the power supply in the two-wire discharge circuit of the battery, and U dc* denotes a specified value of the predetermined bus voltage.

[0057] It should also be noted that in the embodiments of the present disclosure, the PI controllers may be separate from the device for controlling the two-wire discharge circuit of the battery or may be integrated into the device for controlling the two-wire discharge circuit of the battery, which is not described multiple times in the embodiment of the present disclosure.

[0058] That is, in the technical solution according to the second embodiment of the present disclosure, a full-bus voltage outer loop and a closed loop of an average value of inductance currents or an actual value of an inductance current are taken as the master control loop of the two-wire discharge circuit of the battery. In this way, energy balance can be realized while ensuring a stable full-bus voltage. Even in a case where the master control loop controls an output, a duty ratio of a switching transistor in each of the discharge branches is adjusted to control the circuit to independently charge and discharge a half-bus corresponding to the discharge branch, thereby balancing the bus voltage while realizing energy balance. Further, technical indicators in the three-wire connection of the battery are maintained.while eliminating the battery neutral connection and without adding any additional circuitry, and improving the circuit performance of the battery's two-wire discharge circuit.

[0059] Furthermore, in the technical solution according to the second embodiment of the present disclosure, for each of the discharge branches, a PWM signal obtained by performing PI control on a difference between the average value of the inductor currents and the actual value of the inductor current in the discharge branch is taken as a fine adjustment amount of a modulation wave of the discharge branch, and the fine adjustment amount is added to a control amount of a duty ratio of a switching transistor in the discharge branch to realize current sharing of the inductor current and further reduce the discharge ripples of the battery and improve the circuit performance.

[0060] Although the preferred embodiments of the present invention have been described, further changes and modifications may be made by those skilled in the art once they are aware of the basic inventive concept, and the appended claims cover the preferred embodiments and all changes and modifications within the scope of the present disclosure.

[0061] Those skilled in the art may make various changes and variations to the present disclosure without departing from the spirit and scope of the present disclosure, in which case the present disclosure covers these changes and variations if the changes and variations of the present disclosure fall within the scope of the claims of the present disclosure and the equivalent technology thereof.

Claims

[1] A method for controlling a two-wire discharge circuit of a battery, comprising: Determining (201) a positive bus voltage and a negative bus voltage in the two-wire discharge circuit of the battery and comparing the positive bus voltage with the negative bus voltage to obtain a first voltage difference signal; Controlling (202) the first voltage difference signal by means of a proportional-integral PI controller to obtain a first pulse width modulation PWM signal; for each of the first discharge branches in the two-wire discharge circuit of the battery, taking (203) a sum of the first PWM signal and a determined initial master control PWM signal corresponding to the first discharge branch as a set master control PWM signal corresponding to the first discharge branch, and performing (204) a control on a switching transistor for controlling a charge-discharge period of a bus capacitor in the first discharge branch by means of the set master control PWM signal corresponding to the first discharge branch, wherein one terminal of the first discharge branch is connected to a positive electrode of a power supply in the two-wire discharge circuit of the battery and the other terminal of the first discharge branch is connected to a system neutral point; and for each of the second discharge branches in the two-wire discharge circuit of the battery, taking (203) a difference between a determined initial master control PWM signal corresponding to the second discharge branch and the first PWM signal as a set master control PWM signal corresponding to the second discharge branch, and performing (204) a control on a switching transistor for controlling a charge-discharge period of a bus capacitor in the second discharge branch by means of the set master control PWM signal corresponding to the second discharge branch, wherein one terminal of the second discharge branch is connected to a negative electrode of the power supply in the two-wire discharge circuit of the battery and the other terminal of the second discharge branch is connected to the system neutral point, wherein, for each of the discharge branches, the initial master control PWM signal corresponding to the discharge branch is obtained by controlling the two-wire discharge circuit of the battery in a double-loop control manner having a full-bus voltage outer loop and a closed loop of an average value of inductance currents in the two-wire discharge circuit of the battery, or by controlling the discharge branch in a double-loop control manner having a full-bus voltage outer loop and a closed loop of an actual value of an inductance current in the discharge branch. [2] A method for controlling the two-wire discharge circuit of the battery according to claim 1, wherein, in a case where, for each of the discharge branches, the initial master control PWM signal corresponding to the discharge branch is obtained by controlling the two-wire discharge circuit of the battery in the manner of a double-loop control having the full-bus voltage outer loop and the closed loop of the average value of the inductance currents in the two-wire discharge circuit of the battery, the initial master control PWM signal corresponding to the discharge branch is determined by: Comparing a sum of the detected positive bus voltage and the detected negative bus voltage in the two-wire discharge circuit of the battery with a predetermined value of a predetermined bus voltage to obtain a second voltage difference signal; Controlling the second voltage difference signal by means of a PI controller to obtain a predetermined value of an inductance current; Comparing the predetermined value of the inductance current with an average value of the inductance currents in the two-wire discharge circuit of the battery to obtain a first current difference signal; and Controlling the first current difference signal by means of a PI controller to obtain a second PWM signal, and taking a sum of the second PWM signal and a predetermined feedforward signal as an initial master control PWM signal corresponding to the discharge tap. [3] A method for controlling the two-wire discharge circuit of the battery according to claim 1, wherein, in a case where, for each of the discharge branches, the initial master control PWM signal corresponding to the discharge branch is obtained by controlling the discharge branch in the manner of a double-loop control having the full-bus voltage outer loop and the closed loop of the actual value of the inductance current in the discharge branch, the initial master control PWM signal corresponding to the discharge branch is obtained by: Comparing a sum of the detected positive bus voltage and the detected negative bus voltage in the two-wire discharge circuit of the battery with a predetermined value of a predetermined bus voltage to obtain a second voltage difference signal; Controlling the second voltage difference signal by means of a PI controller to obtain a predetermined value of the inductance current; Comparing the predetermined value of the inductance current with the actual value of the inductance current in the discharge branch to obtain a second current difference signal; and Controlling the second current difference signal by means of a PI controller to obtain a third PWM signal, and taking a sum of the third PWM signal and a predetermined feedforward signal as an initial master control PWM signal corresponding to the discharge tap. [4] A method for controlling the two-wire discharge circuit of the battery according to claim 1 or 2, wherein, in a case where, for each of the discharge branches, the initial master control PWM signal corresponding to the discharge branch is obtained by controlling the two-wire discharge circuit of the battery in the manner of a double-loop control having the full-bus voltage outer loop and the closed loop of the average value of the inductance currents in the two-wire discharge circuit of the battery, the method further comprises: for each of the discharge branches in the two-wire discharge circuit of the battery Comparing the mean value of the inductance currents in the two-wire discharge circuit of the battery with the actual value of an inductance current in the discharge branch to obtain a third current difference signal; Controlling the third current difference signal using a PI controller to obtain a fourth PWM signal; and Adding the fourth PWM signal and the adjusted master control PWM signal corresponding to the discharge branch to obtain a newly adjusted master control PWM signal corresponding to the discharge branch, and performing a drive on the switching transistor to control the charge-discharge period of the bus capacitor in the discharge branch by means of the newly adjusted master control PWM signal corresponding to the discharge branch. [5] A method for controlling the two-wire discharge circuit of the battery according to claim 2 or 3, wherein the predetermined feedforward signal is 1-U batt / U dc * is designated, U batt a power supply voltage of a power supply in the two-wire discharge circuit of the battery and U dc * denotes a predetermined value of a predetermined bus voltage. [6] Device for controlling a two-wire discharge circuit of a battery, comprising: an initial signal detection module configured to: obtain, for each of the discharge branches in the two-wire battery discharge circuit, an initial master control PWM signal corresponding to the discharge branch by controlling the two-wire battery discharge circuit in a dual-loop control manner having a full-bus voltage outer loop and a closed loop of an average value of inductance currents in the two-wire battery discharge circuit, or by controlling the discharge branch in a dual-loop control manner having a full-bus voltage outer loop and a closed loop of an actual value of an inductance current in the discharge branch; a fine-tuning signal detection module (82) configured to: detect a positive bus voltage and a negative bus voltage in the two-wire discharge circuit of the battery, compare the positive bus voltage with the negative bus voltage to obtain a first voltage difference signal; control the first voltage difference signal using a proportional-integral PI controller to obtain a first PWM signal;for each of the first discharge branches in the two-wire discharge circuit of the battery, taking a sum of the first PWM signal and the determined initial master control PWM signal corresponding to the first discharge branch as a set master control PWM signal corresponding to the first discharge branch, wherein one terminal of the first discharge branch is connected to a positive electrode of a power supply in the two-wire discharge circuit of the battery and the other terminal of the first discharge branch is connected to a system neutral point;and for each of the second discharge branches in the two-wire discharge circuit of the battery, taking a difference between the determined initial master control PWM signal corresponding to the second discharge branch and the first PWM signal as the adjusted master control PWM signal corresponding to the second discharge branch, wherein one terminal of the second discharge branch is connected to a negative electrode of the power supply in the two-wire discharge circuit of the battery and the other terminal of the second discharge branch is connected to the system neutral point; and; a circuit drive control module (83) configured to perform, for each of the discharge branches in the two-wire discharge circuit of the battery, a drive on a switching transistor for controlling a charge-discharge period of a bus capacitor in the discharge branch by means of the set master control PWM signal corresponding to the discharge branch. [7] A device for controlling the two-wire discharge circuit of the battery according to claim 6, wherein the initial signal detection module (81) is designed to: Comparing a sum of the detected positive bus voltage and the detected negative bus voltage in the two-wire discharge circuit of the battery with a predetermined value of a predetermined bus voltage to obtain a second voltage difference signal; Controlling the second voltage difference signal by means of a PI controller to obtain a predetermined value of an inductance current; Comparing the predetermined value of the inductance current with the average value of the inductance currents in the two-wire discharge circuit of the battery to obtain a first current difference signal; and Controlling the first current difference signal by means of a PI controller to obtain a second PWM signal, and taking a sum of the second PWM signal and a predetermined feedforward signal as an initial master control PWM signal corresponding to each of the discharge branches in the two-wire discharge circuit of the battery. [8] A device for controlling the two-wire discharge circuit of the battery according to claim 6, wherein the initial signal detection module (81) is designed to: Comparing a sum of the detected positive bus voltage and the detected negative bus voltage in the two-wire discharge circuit of the battery with a predetermined value of a predetermined bus voltage to obtain a second voltage difference signal; Controlling the second voltage difference signal by means of a PI controller to obtain a predetermined value of the inductance current; and for each of the discharge branches, comparing the predetermined value of the inductance current with an actual value of an inductance current in the discharge branch to obtain a second current difference signal, controlling the second current difference signal by means of a PI controller to obtain a third PWM signal, and taking a sum of the third PWM signal and a predetermined feedforward signal as an initial master control PWM signal corresponding to the discharge branch. [9] Device for controlling the two-wire discharge circuit of the battery according to claim 6, in which the fine-tuning signal detection module (82) is configured to: in a case where, for each of the discharge branches, the initial master control PWM signal corresponding to the discharge branch is obtained by controlling the two-wire discharge circuit of the battery in the manner of a double-loop control having the full-bus voltage outer loop and the closed loop of the average value of the inductance currents in the two-wire discharge circuit of the battery Comparing the mean value of the inductance currents in the two-wire discharge circuit of the battery with an actual value of an inductance current in the discharge branch to obtain a third current difference signal; Controlling the third current difference signal using a PI controller to obtain a fourth PWM signal; and Adding the fourth PWM signal and the adjusted master control PWM signal corresponding to the discharge branch to obtain a newly adjusted master control PWM signal corresponding to the discharge branch; and the circuit drive control module (83) is configured to perform, for each of the discharge branches of the two-wire discharge circuit of the battery, a drive on the switching transistor for controlling the charge-discharge time period of the bus capacitor in the discharge branch by means of the newly adjusted master control PWM signal corresponding to the discharge branch. [10] Device for controlling the two-wire discharge circuit for the battery according to claim 7 or 8, wherein the predetermined feedforward signal is 1-U batt / U dc * is designated, U batt a power supply voltage of a power supply in the two-wire discharge circuit of the battery and U dc* denotes a predetermined value of the predetermined bus voltage.

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